4628 didik prasetyoko 08. inorganic chemistry

8/9/2019 4628 Didik Prasetyoko 08. Inorganic Chemistry

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The First International Seminar on Science and Technology

January 24, 2009

ISBN : 978 – 979 – 192 1 – –

Study of H-Zeolite Addition in The Esterification Step of Biodiesel Synthesis

from used Cooking Palm Oil

Karna Wijaya, Triyono and Risqi Andini

Laboratory of Physical Chemistry,

Department of Chemistry, Gadjah Mada University

Jl.Kaliurang, Km 5.5, Sekip Utara, Yogyakarta 55218Telp./Fax.: 0274-545188

Correspondence author: [email protected], Mobile phone: 08122692493

Abstract

It has been studied the effect of H-zeolite addition in esterifiction step of biodiesel synthesis from usedcooking palm oil using a steinlessteel biodiesel reactor with capacity of 10 L and equipped with an automatictemperature control, a timer, and a stirrer.

The study was initiated with natural zeolite activation using technical sulfuric acid. After activation thezeolite was characterized its acidity by gravimetric method, its structure by X-ray diffractometry, and FT-IR.The H-zeolite then was used as solid acid catalyst in esterification step of biodiesel synthesis to decrease thefree fatty acid concentration in used palm oil. The H-zeolite which was used in the process was varied itsweight towards (oil + methanol) weight i.e. 1.50%; 3.50%; 5.50% and 6.50%. As a comparison, pretreatment

of used cooking palm oil also has been done over 1.50 % sulfuric acid. After pretreatment, the oil wasseparated from methanol and H-zeolite, the reaction was continued by transesterifying the oil with methanol

using NaOH as catalyst. The transesterification product then was labeled as biodiesel. Both esterification andtransesterification process were carried out in a steinlessteel biodiesel reactor at temperature of 70

oC for 2

hours. The composition of the biodiesel was analyzed using Gas chromatography–Mass Spectroscopy (GC-MS), 1H-NMR and their physical properties were analyzed using ASTM analysis methods.

The research results showed that activation resulted in no destruction of zeolite structure and increased itsacidity. Biodiesel reactor can used for biodiesel synthesis from used cooking palm oil. Addition of H-zeolitein esterfication could decrease its free fatty acid content. Increasing of H-zeolite would increase the biodieselconversion. The highest conversion of biodiesel was 98,41% achieved by addition of H-zeolite of 5.5%

(w/w). The result of GC-MS analysis showed that main components of biodiesel were mixture of methylesters with methyl oleic as the major compound (40.66%). Based on the ASTM analysis data, the obtained

biodiesel specification was in agreement with diesel fuel specification for automotive.

Key words: esterification,transesterifiction, biodiesel, used palm oil, H-zeolite,

Introduction

The international demand for biodiesel and

the promotion of the oil as sources of renewableenergy which can decrease the greenhouse effect are

increasing year after year. Biodiesel can be used in

almost diesel engine when mixed with fossil dieseloil. Biodiesel can provide benefits including:

reduction of greenhouse gas emissions and fossil fuel

use, increase rural development and a sustainable fuel

supply. However, biodiesel have some limitations

such as the feedstocks for biofuel production must bereplaced rapidly [1-10]

Biodiesel is consisting of fatty-acid alkyl

esters, known as FAME (fatty-acid methyl ester).Fatty-acid alkyl esters are long chains of carbon

molecules with an alcohol molecule attached to one

end of the chain. In a process called

transesterification, vegetable oils, animal fats or

restaurant greases are combined with alcohol andchemically altered to form fatty esters such as methyl

ester [8-14]

Beside fresh vegetables oil, used cooking oilmay be used as raw material for biodiesel syntheses.

However, used cooking oil which has been heated inhigh temperature usually contain high concentration

of free fatty acids. Free fatty acids will create soapand hinder the formation of biodiesel in

transesterification reaction step. One of the method to

deal with this is by giving a preliminary treatment on

used cooking oil in the form of an acid catalyst

adding before transesterification is conducted. The

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)

purpose of the treatment is to reduce free fatty acidsconcentration in used palm cooking oil through

esterification reaction. In the esterification reaction

step,usually a catalyst homogen such as sulfuric acid

was used. The use of sulfuric acid as catalyst inindustry is not considered economical becausesulfuric acid used is mixed with alcohol, so that it is

difficult to separate them, moreover sulfuric acid

which is containing sulfur can decrease the quality of

the biodiesel as fuel. As an alternative, a solid acidcatalyst such as acidified zeolite is used [13-19].

Materials And Methods

Materials

The natural zeolite was supplied byPT.Anindya Divisi Pertambangan, Yogyakarta.

Technical grade Sodium hydroxide, methanol andsulfuric acid were used as received. Aquabidest as adispersion media was purchased from Lab.of Physical

Chemistry, Gadjah Mada University. Used cooking

palm oil was purchased from CV.Kembang

Nusantara,Yogyakarta.

InstrumentationsThe X-Ray diffraction (XRD) patterns were

obtained on Shimadzu PW3710 BASED

diffractometer equipped with Shimadzu X-ray

generator, using CuK α radiation. The scanning (2θ)range was from 2 to 40o and the scanning rate was

5o

/min. FTIR spectra was obtained from ShimadzuFTIR-8201 PC. Concentration of biodiesel was

determined using 1H-NMR (60 MHz) and Gas

Chromatography (HP 5890 Shimadzu), meanwhilecomponents of biodiesel were determined using Gas

Chromatography–Mass Spectrometer (Shimadzu).

Synthesis and Characterization of H-ZeoliteThe study was initiated with natural zeolite

activation using technical sulfuric acid. One hundered

gram natural zeolite with dimension of 250 mesh wasdispersed into 1,6M technical grade sulfuric acid. The

dispersion was stirred and then filtered. The solid

phase was heated at 120

o

C for 5 hours. The productwas labeled as H-zeolite. After activation the H-zeolite was characterized its acidity by gravimetric

method, its structure by X-ray diffractometry, and

FT-IR. To calculate methyl esters content we used

proton-NMR data and equation 1.

( ) ( TAG ME ME

ME I I

I C

×+×

××=

95

5%100 (1)

WhereCME =conversion of methyl ester (%)

IME =integrtion value of methyl ester peaks (%)

ITAG =integration value of triasylglicerol (%)

Synthesis of Biodiesel

The H-zeolite which was used in the process

was varied its weight towards (oil + methanol) weight

i.e. 1.50%; 3.50%; 5.50% and 6.50%. As acomparison, pretreatment of used cooking palm oil

also has been done over 1.50 % sulfuric acid. After

pretreatment, the oil was separated from methanoland H-zeolite, the reaction was continued by

transesterifying the oil with methanol using NaOH as

catalyst. The transesterification product then was

labeled as biodiesel. Both esterification andtransesterification process were carried out in a

steinlessteel biodiesel reactor at temperature of 70oC

for 2 hours (Fig.1). The composition of the biodiesel

was analyzed using Gas chromatography–MassSpectroscopy (GC-MS), 1H-NMR and their physical

properties were analyzed using ASTM analysis

methods.

Figure.1 Biodiesel reactor with capacity of 10 L to prepare biodiesel from used cooking plm oil

Results And Discuccion

Preparation of H-Zeolite

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The study was initiated with natural zeoliteactivation using technical sulfuric acid. After

activation the zeolite was characterized its acidity by

gravimetric method, its structure by X-ray

diffractometry, and FT-IR. From X-ray analysis result

could be concluded that the acid activation resulted inno destruction of the natural zeolite structure

significantly. It can be seen clearly from the reflexes

of H-zeolite in its difractogram which almost all of

the reflexes still exist after acid activation (Fig.2)

Figure. 2 Difractogram of natural zeolite (above) and H-zeolit (below)

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Figure 3. FT-IR Spectra of H-zeolite (above) and natural zeolite (below)

Infra red analysis result also supported the

X-ray analysis data. There was no indication that acid

activation caused a significant distruction of zeolitestructure. After activation all importance vibrationts

of the zeolite still appeared in H-zeolite spectra

(Fig.3).Gravimetry analysis indicated that acid

activation can cause the increasing of total acidity ofthe clay in some extent (from 0.02980 mmol

NH3/gram to be 0.03125 mmol NH3/gram) . Theincrease of the acid uptake indicated that the surface

area and adsorption sites of the H-zeolite was higher

than natural unmodified zeolite, Therefore, it is

expected that H-zeolite has catalytic properties higher

than natural unmodified zeolite.

Synthesis of Biodiesel

Biodiesel reactor with capacity of 10 L canused for biodiesel synthesis from used cooking palm

oil. The product and the used cooking palm oil are

displayed in Fig.4. The color of obtained biodieselwas bright yellow meanwhile used cooking palm oil

was dark brown. The characterization result indicated

that addition of H-zeolite in esterfication could

decrease its free fatty acid content from 4.166% to

1.58% .

Figure 4. Used cooking palm oil (left) and biodiesel(right)

To determine the methyl esters concentrationin product we used proton-NMR analysis method.

Analysis results (Fig.3, Fig.4.and Fig.5) exhibited that

esterification and transesterification resulted in theformation of biodiesel which indicated by appearing a

sharp peak around 3,7 ppm at its spectrogram (Fig.

7). Calculation using equation 1 showed that the

increasing of H-zeolite would increase the biodiesel

conversion. The highest conversion of biodiesel was98,41% achieved by addition of H-zeolite of 5.5%

(w/w).

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Figure. 5. Proton-NMR spectra of used cooking palm oil

Fig. 6. Proton-NMR spectra of esterification product


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Fig. 7. Proton-NMR spectra of biodiesel

The result of GC and GC-MS analysisshowed that main components of biodiesel were

mixture of methyl esters with methyl oleic as the

major compound ca. 40.66% (Fig. 8-12). Othercomponets were methyl palmitic (34,37%), linoleic

(13,12%) and stearic (6,84%) (Fig. 9-12).

Figure.8 Chromatogram of mixed methyl esters

The existence of methyl palmitic was indicated by the

appearance of fragment with m/z= 270, 239 and 74

(Fig.9). The appearance of fragments with m/z = 294,

263, 81,55 and 41 was considered due to methyllinoleaic (Fig. 10). Fragments with m/z = 296, 266,

264, 74, 69, 55 and 41 was caused by methyl oleic

(Fig.11). Finally, the methyl stearic appeared with

m/z = 87, 101, 115, 129, 143, 157, 171, 185, 199,

213, 227, 241, and 225 (Fig.12).


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C3H6O2m/z = 74

O

OCH3

C16H31O

m/z = 239

Figure 9. Mass spectra and structure of methyl palmitic

OCH3

O

C18H30Om/z = 262

Figure 10. Mass spectra and structure of methyl linoleic

OCH3

O

C18H32O

m/z = 264 Figure 11. Mass spectra and structure of methyl oleic


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C3H6O2m/z = 74

O

OCH3

C18H35Om/z = 267

Figure 12. Mass spectra and structure of methyl stearic

Biodiesel produced from the above metioned

process are further tested their physicochemical

properties using ASTM method and are comparedwith the specification of ASTM biodiesel (Table 1).

Biodiesel resulted from esterification with H-zeolite

and transesterification proved to fulfil 8 criteria

stipulated for diesel oil, which include viscosity,density, flash point, water content, Conradson carbon

residue, fuel value and specific density. Viscosity of

biodisel is related to specific density in which the

higher the viscosity was, the greater the specific

density would be. Biodiesel with high specific density

will be difficult to flow so that it will slow down theignition process. Biodiesel viscosity from used

cooking palm oil had lower viscosity than used oil,and if it is used as fuel for diesel engine, the result of

injection in ignition chamber will easily form nebula

which facilitate ignition.

Flash point of biodiesel from used cooking

palm oil is relatively very high. The high flash point

make biodiesel easy for storing. The biodiesel can besaved easily and safely in tropical areas. If flash point

of the biodiesel was lower, the biodiesel will be easily

flammable in storing. Biodiesel from used cooking

palm oil is considered to have high pour point. Thehigh pour point cause the diesel engine to stuck in

lower temperature so that it is not suitable for use in

sub tropical areas.

The comparison between specification of

biodiesel produced in the research with specification

of diesel oil for industry and automotive was shownin Table 1. Of the five criteria presented, our

biodiesel fulfil the requirements for being alternativefuel for diesel oil for industry and auttomotive.

Table 1. Comparison between physical characteristic of biodiesel with diesel oil for industry

and automotive diesel oil.

ParameterUsed cooking

palm oil

Automotive diesel

oil*)Industry

diesel oil*)

Specific density 60/60 oF 0,9124 0,820-0,870 0,840-0,920

Brutto fuel value (GHV),BTU/lb **)

19173,25 19031-19220 18842-19145

Netto fuel value (NHV),BTU/lb **) 17423,52 17856-17977 17735-17929

Kinematic viscosity 40oC 40,37 2,0-5,0 7,000

Pour point, oF 39,2 65,000 65,000

Flash point, oF 341,6 Min 150 Min 150

Conradson carbon residue % 0,391 Max 0,100 Max 1,000

Water content, % vol. 0,12 Max 0,05 Max 0,05


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Conclusions

The research results showed that activation

resulted in no destruction of zeolite structure and

increased its acidity. Biodiesel reactor can used for biodiesel synthesis from used cooking palm oil.

Addition of H-zeolite in esterfication could decrease

its free fatty acid content. Increasing of H-zeolite

would increase the biodiesel conversion. The highestconversion of biodiesel was 98,41% achieved by

addition of H-zeolite of 5.5% (w/w). The result of

GC-MS analysis showed that main components of

biodiesel were mixture of methyl esters with methyl

oleic as the major compound (40.66%). Based on theASTM analysis data, the obtained biodiesel

specification was in agreement with diesel fuelspecification for automotive.

References

1. Arrowsmith, C.J., J. Ross, 1945, Treating Fatty Materials, US Patent , 2,383,580.

2. Canakei, M., dan Van Gerpen, J., 2003, A

Pilot Plant to Produce Biodiesel from HighFree Fatty Acids Feedstocks, Am. Soc.

Agric, Eng., 46, 945-954.

3. Demirbas, A., 2003, Biodiesel Fuels fromVegetable Oils via Catalytic and Non-

Catalytic Supercritical Alcohol

Transesterifications and Other Methods: A

Survey, J. Tur. Chem. Educ., 44, 2093-2109.4. Freedman, B., 1984, Variables Affecting the

Yield of Fatty Aster from TransesterifiedVegetables Oil, J: Am. Oil Chem, 10,61.

5. Hamdan, H., 1992, Introduction to Zeolites:

Synthesis, Characterization, and Modification, Universiti Teknologi

Malaysia, Kuala Lumpur.

6. Hanna, A.M., dan Ma, F., 1999, Biodiesel

Production Areview, J., Agric & Natural, 70,

1-15.

7. Hardjono, A., 2001, Teknologi Minyak Bumi,

Edisi pertama, Gadjah Mada UniversityPress, Jogjakarta.

8. Hidayat, D, 2008, Pengaruh katalis H-Zeolit

pada Proses Pembuatan Biodiesel dari Minyak Jelantah kelapa Sawit Bekas

Menggunakan Reaktor Biodiesel

berkapasitas 10 L, Skripsi, Universitas

Gadjah Mada, Jogjakarta.

9. Houas, A. Lachleb, H., Puzenut, E., Ksibi,M., Elaleui, E., Gullard, G., and Hermann,

J.M., 2001, Photocatalytic Degradation

Pathway of Methylene Blue in Water, Appl.

Catal. B: Environmental 30. 145-157.10. Keim, G.I., 1945, Treating Fats and FattyOils U.S., Patent, 383.

11. Knothe, G., 2000, Monitoring a Progressing

Transesterification Reaction by Fiber-Optic

Near Infrared Spectroscopy with correlationto H Nuclear Magnetic Resonance

Spectroscopy, Jpn. Am. Oil. Chem. Soc., 77,

J 9483, 489-493.12. Mastutik, D., 2006, Transesterifikasi Minyak

Jelantah Kelapa Sawit menjadi Biodiesel

Menggunakan Zeolit-Y Melalui Proses

Esterifikasi, Tesis, Universitas GadjahMada, Jogjakarta.

13.

Nye, M.J., dan southwell, P.H., 1983, Esters

from Repeseed Oil as Diesel Fuel In: Proc.

Vegetable Oil as Fuel Seminar III, Pcoria: Northern Agricultural Energy Center, 78-83.

14. Oudejans, J.C., 1984, Zeolite Catalysis in

Some Organic Reactions, ChemicalResearch (SON), Holland.

15. Patzer, R., dan Norris, M., 2002, Evaluated

Biodiesel Made from Waste Fats and Oils,

Final report, Agriculture Utilization

Research Institute, University of Minnesota,Minnesota.

16. Saefudin, A., 2005, Sintesis Biodiesel

Melalui reaksi esterifikasi Minyak Jelantah Dengan Katalis Montmorillonit Teraktivasi Asam Sulfat Yang Dilanjutkan Dengan

Reaksi Transesterifikasi Terkatalisis NaOH ,

Skripsi, Universitas Gadjah Mada,Jogjakarta.

17. Setyawan, D.A., 2001, Pengaruh Waktu dan

temperatur Hidrotermal terhadap

Dealuminasi dan Keasaman Zeolit Alam

Aktif , Skripsi, FMIPA UGM, Yogyakarta.18. Van, Gerpen, J., Shanks, B., Pruszko, R.,

2004, Biodiesel Production Technology,

National Renewable Energy Laboratory,

Collorado.19. Zappi, M., Hernandez, M., Spark, D., Horne,

J., Brough, M., 2003, A Review of the Engineering Aspects of the Biodiesel

Industry, MSU Environmental Technology

Research and Applications Laboratory Dave

C. Swalm School of Chemical Engineering

Mississippi State University, Mississippi.


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Preparation of Solid Acid Catalysts from Bentonite and Their Catalytic

Activities for The Esterification of Jatropha curcas Seed Oil

Novizar Nazir 1,3, Djumali Mangunwidjaja2, Mohd. Ambar Yarmo3 Jumat Salimon3

and Nazaruddin Ramli3

1 Faculty of Agricultural Technology, University of Andalas Padang, Indonesia

Kampus Limau Manis. Padang 25163, Indonesia

Telp. +62 751 72772- E-mail address: [email protected] 2 Department of Agroindustrial Technology, Institut Pertanian Bogor

Kampus IPB Darmaga, Bogor, Indonesia3School of Chemical Science and Food Technology, FST UKM, Malaysia

43600 UKM, Bangi, Selangor Darul Ehsan, Malaysia

Abstract

The esterification reaction of Jatropha curcas seed oil with methanol to remove free fatty acid (FFA)

for biodiesel production was conducted using various bentonite catalysts. Solid acid catalysts from bentonite were prepared by aqueous impregnation technique. 5.3 M HCl and 40% by mass of H2SO4

were supported on bentonite by aqueous impregnation, washed with deionized water till Cl -1 and SO4-

2 ions were not detected, dried overnight and calcinated at 500 oC for three hours. Catalysts was

characterized by XRD, nitrogen adsorption-desorption, and pyridine adsorption FTIR. Five catalysts

used in esterification reactions of Jatropha curcas seed oil with methanol were compared: (A) non-

activated bentonite; (B) HCl 5.3 M-activated bentonite; (C) HCl 5.3 M-activated bentonite and

calcinated at 500 oC (D) H2SO4 40%-activated bentonite; (E) H2SO4 40%-activated bentonite and

calcinated at 500 oC. The effects structure properties of bentonite catalysts were discussed relating

to the conversion of the FFA.

Keywords: Jatropha curcas, solid acid catalyst, esterification, acid-activated bentonite, FFA,

biodiesel

Introduction

With the increasing price of petroleum and

environmental concerns over pollution caused by the

internal combustion gases, alternative fuels have been

developed [1, 2]. Biodiesel is considered as one of the

alternative fuels for diesel engines become

increasingly important [3].

Biodiesel is defined as the mono alkyl esters of

long chain fatty acids derived from renewable

feedstocks, such as vegetable oil or animal fats, use in

compression ignition engine [4]. It is a clean-burningfuel, biodegradable, nontoxic and has low emission

profiles and so is environmentally beneficial. Use of

biodiesel has the potential to reduce the level of

pollutants and of potential carcinogens [5,6,7].

In biodiesel production, the use of edible oils will

compete with the food product. Consequently, the

use of non-edible oil as alternative source will be

important. Among several non-edible oil seed species

could be utilized as source for oil production, J.

curcas which grows in tropical and sub-tropical

climates accross developing world is a multipurpose

species with many attributes and potentials [8,9]

However, the relatively higher amounts of free fatty

acids (FFA) and water in this feedstock results in the

production of soap in the presence of alkali catalyst.

During alkaline-catalyzed transesterification, high

content FFA will react with alkali catalysts to produce

soaps which will inhibit the transesterification for

biodiesel production. Furthermore, the large amount

of soap can gel and also prevent the separation of theglycerol from the ester [5]. Acid-catalyzed

transesterification, despite its insensitivity to FFA in

the feedstock, has been largely ignored mainly

because of its relatively slower reaction rate [6].

Therefore a process combining pretreatment withalkaline-catalyzed transesterification for feedstocks

having high FFA content was investigated by many

authors [10,11,12,3].

Acid-catalyzed esterification of high FFA content

vegetable oils is a typical method of biodiesel

production due to high reaction speed and high yield

[13]. Some raw feedstocks with high FFA such as

yellow and brown grease [10], rubber seed oil [11]

mahua oil [14], waste cooking oil [15] and jatropha

oil [11] have been used to produce biodiesel with

homogeneous acid-catalyzed esterification followed

by transesterification using alkaline catalyst.

Compared with conventional liquid acid catalysts,

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solid acid catalyst is more environmentally friendly

[15].

The present work was undertaken to investigate

the pretreatment process for reducing the FFA content

of jatropha oil for biodiesel production using various

bentonite as solid acid catalyst. This paper focuses on

the reaction parameters that affect the conversion of

FFA in crude jatropha oil by means of acid-catalyzed

esterification with methanol.

Materials and Methods

Materials

Jatropha curcas oil was hydrolic press extracted of

jatropha seed from Lampung, South Sumatra,

Indonesia. Anhydrous methanol (MeOH), 99.8%,

potassium hydroxide (KOH), sulfuric acid (H2SO4),

and Hydrochloric acid (HCl), 37-38% pure were

purchased from ChemAR ®.

A calcium-rich bentonite (CaB) sample was

obtained as powder from PT. Superintending

Company of Indonesia used in the experiments. The

bulk chemical analysis of the bentonite (mass %) is

SiO2, 64.15; TiO2, 0.47; CrO3, 0.003; Al2O3,.70;

Fe2O3, 0.10; MgO, 0.70; CaO, 0.03; , Na2O, 0.20;

K 2O, 0.50 and loss on ignition (LOI), 22.61.

Preparation of Catalyst [16,17]

Acid-activated Bentonite were prepared by aqueous impregnation technique. 5.3 M HCl and

40% by mass of H2SO4 were supported on bentonite

by aqueous impregnation (at 80 oC and 4 h), washed

with deionized water till Cl-1

and SO4-2

ions were not

detected, dried overnight and calcinated at 500 oC for

three hours. Five catalysts for esterification of

jatropha oil with methanol were compared: (A)

“untreated” bentonite catalyst; (B) esterification with

5.3 M HCl-activated bentonite catalyst; (C)

esterification with 5.3 M HCl-activated bentonite and

calcinated at 500oC catalyst (E) esterification with

40% H2SO4-activated bentonite catalyst; (F)

esterification with 40% H2SO4-activated bentoniteand calcinated at 500

oC catalyst.

Characterization of Catalyst

The X-ray diffraction (XRD) patterns of natural

and acid activated samples were recorded from

random mounts prepared by glass slide method using

a Rikagu D-Max 2200 Powder Diffractometer,

operating at 40 kV and 30 mA, using Ni-filtered

CuKa radiation having 0.15418 nm wavelength, at a

scanning speed of 2o2θ min _1. Surface area of bentonite was measured with multipoint Brunauer,

Emmett and Teller (BET) method from the

Quantachrome Surface Analysis Instrument

(Autosorb 1-C, Boynton Beach, Florida, USA). This

was done using nitrogen adsorption/desorption

isotherms at liquid nitrogen temperature and relative

pressures (P/Po) ranging from 0.04- 0.4 where a

linear relationship was maintained. For acidity study,

about 10 mg of the sample was pressed at 2-5 tonnes

for a minute to obtain a 13 mm disk. The sample was

introduced in infrared cell with calcium flourite.

Each sample was degases for 16 hours under vacuum

at 400 °C. The infrared spectra were collected at

room temperature using Simadzu 2000 FTIR

spectrometer at 2 cm-1 resolution. The type of acid

sites were examined using pyridine as probe

molecule. Then pyridine was absorbed for 30

seconds at room temperature, continued by desorption

at 150 °C for 1 hour. Finally, the sample was

desorpted at 400 °C for 1 hour.

Esterification process catalyzed by sulfuric acid

Esterification was conducted in a 250 ml three-

neck flask. The flask was equipped with a

mechanical agitator and a reflux condenser, and

heated with a water bath to control the reaction

temperature (60oC). In the experiments, flasks loaded

with Jatropha oil samples were firstly heated to the

designated temperature. This was followed by the

addition of the methanol (methanol : oil ratio, 0.28

v/v) and sulfuric acid (1.34%) mixture before turning

on the agitator, marking the start of the esterification

reaction.

The application solid acid catalyst in esterification

process

Esterification was conducted in a 250 ml three-

neck flask. In the experiments, flasks loaded with

Jatropha oil samples were firstly heated to the

designated temperature (60oC). This was followed by

the addition of the methanol (methanol : oil ratio, 0.30

v/v) and solid acid catalyst (5% w/v oil) mixture

before turning on the agitator, marking the start of the

esterification reaction. The esterification products

were separated in a tap funnel to obtain the upper oillayer. After methanol recovery under vacuum at

50oC, oil layer was then washed with water several

times until the pH of washing water was close to 7.0.

The resultant esterified oil was dried by anhydrous

magnesium sulfate before acid value analysis.The

convertion of FFA was defined as the fraction of the

FFA removed. The convertion of FFA ( xFFA) was

determined from acid number ration using below

equation [15]:

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Where ai is the initial acid number of the reactant

and at is the acid number of product at ‘t’ time.

0

500

1000

1500

2000

2500

0 5 10 15 20 25 30 35

0

HCl 5.3. M non-calicinated

o2θ

Alkali catalysed transesterification of jatropha oil

The collected oil layer was transferred to 250 ml

round bottom, 0.1g v/v methanol and 3.5 w/v +acid

number of KOH were added. The mixture was

reacted for 24 minutes at 65oC. The mixture was left

to settle to separate into two layers. The upper layer

was the FAME (crude biodiesel).

Results and Discussion

Characterization of Catalyst

Fig. 1 shows changes in intensity and width of

the 001 peak, which indicate that the crystallinity of

the bentonite is considerably affected by acid

activation an calcination. The variation of relative

intensity (I / I0) and full width at half-maximum

(FWHM) peak height of the XRD peak for bentonites

represent the intensities for the natural and acid-

activated bentonite samples, respectively. The

decrease in I / I0 and increase in FWHM on the 001

XRD peak show that the crystallinity of bentonite

decreases by increasing in acid [17].

Fig. 1. The XRD patterns of the natural and some of

the acid-activated bentonite (S: smectite, I:

illite, FWHM: full width at half maximum

peak height).

The total pore volume of samples is measured by

condensation of N2 adsorbate at P/Po 0.95 in the pores

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[a] [b]Fig. 2. FTIR spectra of samples (a) after pyridine adsorption at room temperature for 30 seconds, (b) after

pyridine adsorption and desorption at 150oC for 1 h.

Effect of esterification reaction time and type ofbentonite to acid value

The effect of esterification reaction time and

type of bentonite to acid value is shown in Fig.3.

The results show that the acid value decrease

significantly after 6 hours esterification. The bestcatalyst is HCl-activated bentonite without

calcination with 67.70% FFA convertion after six

hours reaction time. This result is lower than

heterogeneous catalyzed reaction of H2SO4

(91.70% FFA convertion).

Fig.3. Effect of esterification reaction time and type of bentonite to acid value of esterified oil

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Effect of esterification reaction time to convertion

of FFA and acid value

According to Lu et al [18], FFA convertion

will increase with the increasing of time,

temperature and ratio methanol to oil. In thisexperiment we increase the reaction temperature

from 60oC to 65oC and methanol to oil ratio from

0.30 (v/v) to 0.40 (v/v) using catalyst B. The

convertion of FFA and acid value of esterified oil is

shown in Fig.4. The result shows that the

convertion of FFA increase from 67.70% to 81.7%

Fig. 4. Effect of esterification reaction time to convertion of FFA and acid value of esterified oil

Alkali catalysed transesterification of jatropha oil

In this work, the lowest acid value of esterified

jatropha oil was 2.32 mg KOH/g. In fact, the alkali

catalyzed transesterification of jatropha oil could

work, even if the FFA content was over 1% [19].

The reaction of jatropha oil with methanol was easy

to perform. The bottom layer of glycerol wasobvious after 24 minutes reaction time [12].

Chemical properties of jatropha biodiesel obtained

from the FFA removal by esterefication of FFA in

jatropha oil with H2SO4 (at 60oC and 88 minutes

reaction time) and HCl-activated bentonite (at 70oC and 6 hours reaction time) is shown in Table 2.

Table 2. Chemical properties of jatropha biodiesel obtained from the FFA removal by esterefication of FFA in

jatropha oil with H2SO4 (at 60oC and 88 minutes reaction time) and HCl-activated bentonite (at 70

oC and 6 hours reaction time)

Property Product after the

reaction on H2SO4

Product after the

reaction on HCl-

activated bentonite

Density (kg/m2) 0,87 0,87

Kinematic viscosity (mm/s2) 1,73 1,74

Free Fatty Acid (mg KOH/g oil) 0,24 0,47

Conclusion

Based on the result of this study, it can concluded

that:

1. Acid activation and calcination on bentonite

affect the cristalinity, surface area, pore

volume and acidity properties of bentonite.

2. HCl-activated bentonite without calcination has

potential to be solid acid catalyst foresterification of jatropha oil. Convertion of

FFA reached 81.7% when parameters are as

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follows: reaction time 6 h, amount of catalyst

5%, ratio methanol oil 0.4 v/v and reaction

time 65oC.

3. HCl-activated bentonite as acting asheteregeneous acid catalyst shows good

activity to catalyze the esterification of jatropha oil and methanol. Compared with

sulfuric acid, this catalyst is environmentally

friendly, easy to separate from the system,

reusable and does not need high cost

equipment for anti-corrosion

Acknowledgements

The authors thank University Kebangsaan Malaysia

for all facilities and supporting this study by the

Research University Grant UKM-oup-nbt-29-

151/2008.

References

[1] M. Fangrui, A.H. Milford (1999):

Biodiesel production: a review. Bioresour.

Technol. 70, 1–15.

[2] J.M. Marchetti, V.U. Miguel, A.F. Errazu

(2007). Possible methods for biodiesel

production, J. Renew. Sustain. Energy Rev. ,

11, 1300–1311.

[3] H.J. Berchmans,., and S. Hirata (2008).

Biodiesel production from Jatropha curcas L. Seed oil with a high content of free fatty

acids. Bioresour. Technol. 99, 1716-1721.

[4] L.C Meher, V.D. Sagar, S.N. Naik (2006)

Technical aspects of biodiesel production by

transesterification—a review, J.Renew.

Sustain. Energy Rev. 10, 248–268.

[5] A.Demirbaş (2002). Biodiesel fromvegetable oils via transesterification in

supercritical methanol, Energy Conserv.

Manage. 43, 2349–2356.

[6] Y. Zhang, M.A. Dubè, D.D. McLean, M.

Kates (2003). Biodiesel production fromwaste cooking oil: 1. Process design and

technological assessment. Bioresour. Techn.

, 89, 1-16.

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Synthesis and Characterization of Al2O3/TS-1

Rivone Septa Wijayanti, Didik Prasetyoko

Laboratorium of Inorganic Chemistry, Department of Chemistry, Faculty of Mathematic and Sciences, InstitutTeknologi Sepuluh Nopember (ITS), Surabaya, Indonesia.

1)Corresponding author, Phone: +62-31-5943353

email: [email protected][email protected]

Abstract

TS-1 has good catalytic activity in reaction of selective oxidation of organic materials such as benzene and phenol using H2O2 as oxidizing agent. However, it has hydrophobic character thatcorrelate with the slow rate of the reaction. Modification of catalyst using metal oxide result in

decreased of hydrophobic property, and as a sonsequence the rate of the reaction will beincreased. In this paper, TS-1 was modified by Al2O3 using impregnation method. The solid

were characterized by X-ray diffraction, infrared spectroscopy, and hydrophilicity techniques.Hydrophilicity test of Al2O3/TS-1 was carried out using the mixture of xylene and water. The

impregnated catalysts Al2O3/TS-1 show partially hydrophilic property. Al2O3/TS-1 catalyst with4%wt loading demonstrated fastest submerged time at water as compare to other samples. The

addition of Al2O3 increased hydrophilicity of TS-1 which is indicated by the results ofhydrophilicity test.

Key words: catalyst, Al2O3/TS-1, hydrophilic

Introduction

The synthesis of titanium silicalite (TS-1) was first reported by Taramasso et al. [1] in1983. Titanium silicalite-1 (TS-1), a MFI-typetitanosilicate, has been used as a highly-efficient,heterogeneous catalyst for selective oxidation oforganic compounds using hydrogen peroxide as an

oxidant. TS-1 can lessens tar product and side products which have potential as pollutant [2]. Overthe last decade, the literature has reflected a highactivity and selectivity of H2O2 on TS-1 as catalystsfor mild oxidation reactions with H2O2 used as theoxidant, such as phenol hydroxylation, olefins

epoxidation, cyclohexanone ammoximation,

alkane oxidation, oxidation of ammonia tohydroxylamine, secondary amines todialkylhydroxylamines [3].

TS-1 has been commercialize in

hydroxylation reaction of phenol with high

hydroquinone selectivity and high H2O2 efficiency

[4]. Hydroxylation reaction of phenol to produce

diphenol had draws many attention since 1970s,

and some catalysts either homogen and also

heterogeneous have been applied in this reaction

[5].

Reaction mechanism of phenolhydroxylation is as follows (1) TS-1 willdecompose H2O2 (oxidation agent) which has

hydrophilic character to form titanium-peroxoradical (initiation step), then (2) propagation step in

solution [2]. This mechanism can be explained viatitanium-peroxo complex formation mechanism as

intermediate from reaction between H2O2 and TS-1catalyst [6-10]. The rate of the forming of titanium- peroxo depended on the rate of H2O2 reach to activesite in TS-1. H2O2 is hydrophilic, that is quietdifferent from hydrophobic character of TS-1. [11],consequently the reaction rate of phenol

hydroxylation reaction is tends to be slow [7].One of the way to increase phenol

hydroxylation reaction rate by modifieng of catalystTS-1. Hence the existence of modified catalyst willinfluence its the character of chatalytic. The

property of TS-1 modified properties made becomemore hydrophilic character by increasing acidity.The addition of metal oxide is the way to increaseacidity, so the reaction rate of H2O2 with TS-1 toforms Ti-peroxo becomes more quicker. Theaddition of acidity character may come from Lewisacidity site or Brønsted acidity site. In this research

applied Al2O3/TS-1 having acidity side of Lewiswhich is high as metal oxide added at TS-1. So that

also can increase reaction rate of H2O2 with TS-1 toforms Ti-Peroxo which in the end will yield product briefer. Finally the reaction rate of phenolhydroxylation at Al2O3/TS-1 will be much faster

and shows increasing of catalytic activity andselectivity higher than TS-1.

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Material and Methods

For TS-1 (1 mol% of Ti), tetraethyl

orthosilicates, TEOS (Merck, 98%) was placed intoa Teflon beaker and vigorously stirred, tetraethylorthotitanate, TEOT (Merck, 95%) was carefullyadded dropwise into this TEOS. The beaker was

covered with parafilm to avoid hydrolysis. Thetemperature of the mixture was raised to 35oC and

the reactants were mixed homogeneously for halfan hour. Then the mixture was cooled to about 0oC.The solution of TPAOH (Merck, 20% TPAOH inwater), which was used as template, was also

cooled to 0oC.

After a few minutes, TPAOH was added

drop-wise slowly into the mixture of TEOS andTEOT. At first, one should wait a few minutes afteraddition of a few drops of TPAOH solution beforemore TPAOH solution is added, to avoid

precipitation. Stirring and cooling were continuedduring this process. After the addition of about 10

mL the addition rate of TPAOH solution wasincreased. When the addition of TPAOH wascompleted, the mixture was heated in thetemperature range of 80-90oC for about 4 h in orderfor the hydrolysis of TEOS and TEOT to take place. Distilled water was added to increase the

volume of the mixture, after which a clear gel wasobtained. The gel was transferred into autoclaveand heated at 175

oC under static condition. The

material was recovered after 4 days ofhydrothermal crystallization by centrifugation andwashing with excess distilled water. A white

powder was obtained after drying in air at 100oC

overnight. The calcination of the sample to removethe template was carried out under static air at550oC for 5 h with temperature rate at 1o/min.

Samples of Al2O3/TS-1 catalystcontaining 0,5%; 1%; 2%; and 4% were prepared

by impregnation method, titanium silicalit (TS-1)was added to alumunium (III) nitrate solution

which obtained by dissolving alumunium (III)nitrat. This mixture stirred at 80ºC for 3 h, dried at80-90ºC to eliminate water, and calcined at 550ºCfor 5 h. Catalyst TS-1 and Al2O3/TS-1 werecharacterized by X-ray diffraction (XRD) and

infrared spectrum is recorded with Fourier-Transform Infrared (FT-IR) spectrophotometer,with KBr palette method. Hidrophilicity propertiesof samples was analyzed by catalyst sample powder

dispersion method at water phase and organic phasemixture (water and xylene). The movement ofcatalyst sample at each phase was observed.

Result and Discussion

Structural and phase of samples weredetermined by X-ray diffraction. The XRD patternswere showed in figure 1. Characteristic diffraction

line of TS-1 is observed at 2θ = 7.88; 8.78; 23.14;

23.9; 24.39; 2478°. The peak at 2θ around 24º isobserved for the change of crystal symmetry frommonoclinic symmetry, which is symmetry ofsilicalit-1, becomes orthorombic symmetry which issymmetry of TS-1. This Phenomenon indicates that

titanium atom is in the framework structure of TS-1

[12].X-ray diffraktogram pattern of

Al2O3/TS-1 with various Al2O3 loading variation at

TS-1, showed similar pattern. XRD pattern of

Al2O3/TS-1 with various of Al2O3 loading showed

similar pattern with parent sample TS-1 shown in

figure 1. Main top of crystal TS-1 emerges at 2θ =

7.88; 8.78; 23.14; 23.9; 24.39; 24.78°. The similar

pattern of XRD Al2O3/TS-1 indicates that Al2O3

dispersed at surface of titanium silikalit-1.

Therefore, the low content of Fe2O3 (up to 4 %wt)

on TS-1 catalyst surface doesn't change the initial

structure framework of TS-1.

This finding indicated that the MFIstructure of TS-1 is not collapsed afterimpregnation of Al2O3.

Catalyst samples of TS-1 and Al2O3/TS-1 showed absorption band at around 1100, 800, and450 cm-1, which is vibration mode of SiO4 or AlO4

tetrahedral [13]. Absorption band at around 1100cm-1 is unsimmetrical vibration mode of Si-O-Si,and absorption band at around 800 cm-1 is itssymmetrical vibration mode. Absorption bandappeared at around 1230 and 547 cm-1. It is

characteristic of tetrahedral structure in frameworkzeolite MFI [14]. Absorption band appeared ataround 970 cm-1 is characteristic of TS-1 which isvibration mode of stretching Si-O from unit [SiO4]which tied at atom Ti

IV with tetrahedral

coordination in TS-1 framework. Absorption bandappear at this wavenumber is evidence that titaniumatom has stayed in framework catalyst [15].

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2 Al2O3/TS-1

4 Al2O3/TS-1

TS-1

0,5 Al2O3/TS-

1 Al2O

3/TS-1

Figure 1 X-ray powder patterns of samples TS-1 and Al2O3/TS-1 with various loading

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4Al2O3/TS-1

2Al2O3/TS-1

8 0 0 c m

- 1

1Al2O3/TS-1

9 7 0 c m - 1

5 4 7 c m - 1

4 5 0 c m - 1

1 2 3 0 c m - 1

1 1 0 0 c m - 1

0.5Al2O3/TS-1

TS-1

Figure 2 Framework IR Spectra of samples TS-1 and Al2O3/TS-1 with various loading

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Table 1. Hydrophilicity Character Definition

Hydrophilic

Sample pass submerged the interfacial phase into water as a whole andquickly

Hydrophilic Sample pass submerged interfacial phase into water not fairly quickly but in the end all sample is submerged sample

Hydrophilic Initially sample tantalum at interfacial phase and then immerses inwater slowly and as a whole

Partially Hydrophilic

Initially sample tantalum at interfacial phase, then some particle willsubmerged into water slowly and some tantalum particles at interfacial phase, after squealer, all sample is immerses in water

Partially Hydrophobic

Initially sample tantalum at interfacial phase, after squealer, some particles there are still tantalum at interfacial phase

Perfect Hydrophobic

Sample will be tantalum permanently at interfacial phase though aftersquealer is done

Tabel 2. Hydrophilicity Character of TS-1 dan Fe2O3/TS-1

Sample Index Character Water sumerged time

(seconds)

TS-1 5 Partially Hydrophobic 1 minutes 10 second

0,5Al2O3/TS-1 5 Partially Hydrophilic 42 second

1Al2O3/TS-1 5 Partially Hydrophilic 38 second



Hydrophilic test of sample was carryingout using mixture xylen and water [16]. The result

of hydrophilic characterization test of sample isgiven at tables 2.

Table 2 gives an information abouthydrophilicity properties of catalyst samples. Ts-1sample has hydrophobic character. This result issimilar with the research that had been carried out

by Drago [14]. This phenomena is caused by thestructure of TS-1 which active site Ti tetrahedral isisolated

Presence metal oxide at TS-1, characterof hydrophilic increased. This thing proves thatwith presence Al2O3 increased hydrophilicity side

of TS-1 which is indicated from increases Lewis

side acid.

Conclusion

1. Catalyst TS-1, 0,5% Al2O3/TS-1, 1%Al2O3/TS-1, 2% Al2O3/TS-1, and 4%

Al2O3/TS-1 has successfully synthesized.2. The addition of Al2O3 at TS-1 doesn't change

crystal structure TS-1 with zeolite type MFI.3. Catalyst sample TS-1 and Al2O3/TS-1 shows

absorption band at around 1100, 800, and 450cm-1, which is vibration mode of SiO4 or AlO4

tetrahedral. This spectra is characterization ofMFI.

4. With existence of addition of Al2O3 at TS-1,character of hydrophilic increased. Al2O3/TS-

1 4% loading gives submerged time at fastestwater compare to other sample.

Acknowledgements

References

[1] Taramasso, M., Perego, G. and Notari, B.(1983), “Preparation of Porous CrystallineSynthetic Material Comprised of Silicon andTitanium Oxides”. (U. S. Patents No.4,410,501).

[2] Kurian, M., Sugunan, S. (2006), “Wet PeroxideOxidation of Phenol Over Mixed PillaredMontmorillonites”, Chemical Engineering Journal , Vol. 115, pp. 39-146.

[3] Liu, X., Wang, X., Guo, X., Li, G. (2004),“Effect of Solvent on the PropyleneEpoxidation over TS-1 Catalyst”, Catalysis

Today, Vol. 93-95, pp. 505-509.[4] Choi, J., Yoon, S., Jang, S., Ahn, W. (2006),

“Phenol Hydroxylation Using Fe-MCM-41Catalysts”, Catalysis Today, Vol. 111, pp. 280-287.

[5] Tang, H., Ren, Y., Yue, B., Yan, S., He, H.

(2006), “Cu-incorporated MesoporousMaterials : Synthesis, Characterization and

Catalytic Activity in Phenol Hydroxylation”,

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Journal of Molecular Catalysis A : Chemical ,Vol. 260, pp. 121-127.

[6] Vayssilov, G. N. dan van Santeny, R. A.(1998), “Catalytic Activity of Titanium

Silicalites—a DFT Study”, Journal ofCatalysis, Vol. 175, pp. 170–174.

[7] Sun, J., Meng, X., Shi, Y., Wang, R., Feng, S.,Jiang, D., Xu, R., Xiao (2000), “A NovelCatalyst of Cu–Bi–V–O Complex in PhenolHydroxylation with Hydrogen Peroxide”, Journal of Catalysis, Vol. 193, pp. 199–206.

[8] Wilkenhöner, U., Langhendries, G., van Laar,

F., Baron, G. V., Gammon, D. W., Jacobs, P.A., dan van Steen, E. (2001), “Influence ofPore and Crystalline Titanosilicates on PhenolHydroxylation in Different Solvents”, Journalof Catalysis, Vol. 203, pp. 201-212.

[9] Bonino, F., Damin, A., Ricchiardi, G., Ricci,M., Spano`, G., D’Aloisio, R., Zecchina, A.,Lamberti, C., Prestipino, C., dan Bordiga, S.(2004), “Ti-Peroxo Species in The TS-1/H2O2/H2O System”, Journal of PhysicalChemistry B, Vol. 108, pp. 3573-3583.

[10] Liu, H., Lu, G., Yanglong Guo, Yun Guo, dan

Wang, J. (2006), “Chemical Kinetics ofHydroxylation of Phenol Catalyzed by TS-1/Diatomite in Fixed-Bed Reactor”, Chemical Engineering Journal , Vol. 116, pp. 179–186.

[11] Armaroli, T., Bevilacqua, M., Trombetta, M.,Milella, F., Alejandre, A. G., Ramirez, J.,

Notari, B., Willey, R. J., dan Busca, G. (2001),“A Study of The External and Internal Sites ofMFI-Type Zeolitic Materials through TheFTIR Investigation of The Adsorption of Nitriles”, Applied Catalysis A : General , Vol.216, pp. 59–71.

[12] Li, Y.G., Lee, Y.M., Porter, J.F. (2002), “TheSynthesis and Caracterization of TitaniumSilicalite-1”, Kluwer Academic Publishers, pp.0022-2461.

[13] Flanigen. E. M. (1976). Structural analysis byinfrared spectroscopy. In: Rabo, J. A. ed.Zeolite chemistry and catalysis. ACS

Monograph Vol. 171; pp. 80-117.[14] Drago, R., Dias, S. C., McGilvray, J. M.,

Mateus, A. L. M. L., 1997, “Acidity andHidrophobicity of TS-1”, Journal PhysicChemistry B, vol. 102, pp. 1508-1514.

[15] Li, G., Wang, X., Guo, X.,Liu, S., Zhao, Q.,

Bao, X., Lin, L. (2001), “Titanium Species inTitanium Silicalite TS-1 Prepared ByHydrothermal Method”, Materials Chemistryand Physics, Vol. 71, pp. 195-201.

[16] Wang, Z., Wang, T., Wang, Z., Jin, Y. (2004),“Organic Modification of Ultrafine Particles

using Carbon-dioxide as the Solvent”, Journalof Powder Technology, Vol. 139, pp. 148-155.

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Synthesis and Characterization of Fe2O3/TS-1 Catalyst

Cholifah Endahroyani, Didik Prasetyoko

Laboratorium of Inorganic Chemistry, Department of Chemistry, Faculty of Mathematic and Sciences, InstitutTeknologi Sepuluh Nopember (ITS), Surabaya, Indonesia

Corresponding author, Phone: +62-31-5943353email: [email protected]

Abstract

Hydroxylation reaction of phenol into diphenol, such as hydroquinone and cathecol, has a great rolein many industrial applications. Phenol hydroxylation reaction has been carried out by using TitaniumSilicalite (TS-1) as catalyst and H2O2 as an oxidant. TS-1 catalyst has high activity and selectivity for

phenol hydroxylation reaction. However, its hydrophobic sites lead to slow H2O2 adsorption towardthe active site of TS-1. Consequently, the reaction rate of phenol hydroxylation reaction is tends to below. Addition of metal oxide can enhanced hydrophilicity character of TS-1 catalyst. In this research,

TS-1 catalyst was modified by addition of metal oxide Fe2O3 by impregnation method. Fe2O3/TS-1catalyst were characterized by X-ray diffraction, FT-IR spectroscopy and hydrophilicity analysistechniques. The new catalyst, Fe2O3/ TS-1 showed higher hydrophilicity compared to TS-1, and it can

be predicted that the reaction rate of phenol hydroxylation will be much faster and will be showedincreasing of catalytic activity and selectivity than that of parent catalyst, TS-1.

Key words: catalyst, TS-1, Fe2O3/ TS-1, hydrophilic site, phenol hydroxylation

Introduction

Hydroxylation reaction of phenol to produce diphenol (catechol and hydroquinone) and its

isomers is one of important reaction because phenolhas various important functions such as antioxidant, polymerization inhibitor, photography, rubber production, antiseptic, reducing agent, intermediate in pharmacy, and many others. Hydroxylation reactionof phenol to produce diphenol had draws manyattentions since 1970s and some catalysts, bothhomogeneous and heterogeneous have been appliedin this reaction. Hydroxylation reaction of phenol

becomes environmentally friendly reaction when TS-1 (Titanium Silicalite-1) is applied as catalyst andaqueous H2O2 as oxidant [1]. TS-1 had draws manyattention since last decade because its unique catalyticcharacters to selective oxidation reaction of organiccompounds like aromatic hydroxylation, epoxidationalkenes, ammoximation cyclohexanone and oxidationof alkene and alcohol with hydrogen peroxide asoxidant [2]. TS-1 has been commercialize inhydroxylation reaction of phenol with highhydroquinone selectivity (hydroquinone/cathecolratio = 1) and high H2O2 efficiency [3].Hydroxylation reaction of phenol with TS-1 catalystshows high activity and selectivity, become clean

reaction with low H2O2 non-productivedecomposition, and high catalyst stability [4].

TS-1 can lessens tar product and side products which have potential as pollutant. Reaction

mechanism of phenol hydroxylation is as follows: (1)TS-1 will decompose H2O2 (oxidation agent) whichhas hydrophilic character to form titanium-peroxoradical (initiation step), then (2) propagation step insolution [5]. This mechanism can be explained viatitanium-peroxo complex formation mechanism asintermediate from reaction between H2O2 and TS-1catalyst [2, 6-9]. The rate of the formation oftitanium-peroxo depended on the rate of H2O2 reachto active site in TS-1. H2O2 is hydrophilic, that isquite different from hydrophobic character of TS-1[10], consequently the reaction rate of phenolhydroxylation reaction is tends to be low [7]. One ofthe way to increase phenol hydroxylation reaction

rate with TS-1 catalyst is by making TS-1 becomemore hydrophilic character, and the reaction rate of

phenol hydroxylation will be much faster and showsincreasing of catalytic activity and selectivity higherthan TS-1. Hydrophilic improvement of catalyst can

be carried out by addition of metal oxide which leadsto increasing of acidity properties. The existence ofmetal oxide in TS-1 catalyst can gives acid site whichcapable to increase catalyst hydrophilicity, so that

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reactant adsorption in catalyst becomes faster [11,12].Heterogeneous catalytic process in phenolhydroxylation reaction can be carried out with puremetals oxide or supported oxide such as MoO3,

CuO/SiO2, Fe2O3, Fe2O3/Al2O3, Co3O4, V2O5 andcolloid particle of TiO2. However, this metal oxidesshow very low catalytic activity and selectivity [13].

In previous research by Indrayani [14],synthesis and catalytic activity were carried out withlow-loading of MoO3/TS-1 catalyst in phenolhydroxylation reaction. MoO3/TS-1 catalysts haveshowed improvement of hydrophilicity along with theincreasing of MoO3 content in MoO3/TS-1 catalyst.The improvement of hydrophilic character ofMoO3/TS-1 catalyst is also accompanied with theimprovement of its catalytic activity in phenolhydroxylation reaction. In this research, TS-1 catalystwas modified by addition of metal oxide Fe2O3 on thesurface of TS-1. The existence of Fe2O3 on the TS-1surface, is expected to bring this new catalyst(Fe2O3/TS-1) become higher hydrophilic charactercompared to TS-1, and the rate of phenolhydroxylation reaction becomes faster than TS-1.

Experimental

Samples TS-1 were prepared according to a procedure described earlier by Taramasso et al .(1983). Tetraethyl orthosilicates, TEOS (Merck,98%) containing 0.3145 mol of silicon was placed

into a Teflon beaker and vigorously stirred, tetraethylorthotitanate, TEOT (Merck, 95%) containing 0.0032mol of titanium in isopropyl alcohol was carefullyadded dropwise into this TEOS. The beaker wascovered with parafilm to avoid hydrolysis. Thetemperature of the mixture was raised to 35oC and thereactants were mixed homogeneously for half an hourto obtain depolymerisation of the titanate oligomersthat may be present in TEOT. Then the mixture wascooled to about 0oC. The solution oftetrapropylammonium hydroxide, TPAOH (Merck,20% TPAOH in water), which was used as template,was also cooled to 0oC. After a few minutes, TPAOH

containing 0.1287 mol of TPAOH was added drop-wise slowly into the mixture of TEOS and TEOT. Atfirst, one should wait a few minutes after addition of afew drops of TPAOH solution before more TPAOHsolution is added, to avoid precipitation. Stirring andcooling were continued during this process. After theaddition of about 10 mL the addition rate of TPAOHsolution was increased. When the addition of TPAOHwas completed, the mixture was heated in thetemperature range of 80-90oC for about 4 h in order

for the hydrolysis of TEOS and TEOT to take place.Distilled water was added to increase the volume ofthe mixture to about 127 mL, after which a clear gelwas obtained. The gel was transferred into a 150 mL

autoclave and heated at 175

o

C under static condition.The material was recovered after 4 days ofhydrothermal crystallization by centrifugation andwashing with excess distilled water. A white powderwas obtained after drying in air at 100oC overnight.Silicalite was synthesized by using the same

procedure without the addition of TEOT. Thecalcination of the sample to remove the template wascarried out under static air at 550oC for 5 h withtemperature rate at 1o/min [15].

Catalyst TS-1 and Fe2O3/TS-1 ischaracterized with X-ray diffraction (XRD)technique, X-ray powder diffraction (XRD) patternswere collected using the Ni-filtered Cu-K α radiation( λ = 1.5406 Å), the infrared spectrum is used for IRabsorption spectra analysis with KBr palette method.The infrared spectrum is recorded from wavenumber1400–400 cm−1. Catalysts hydrophilicity is analyzed

by catalyst sample powder dispersion method at water phase and organic phase mixture (water and xylene).A mixture of xylene and water, which do not mixwith each other, is employed to test the hydrophobiccharacteristics of the samples. Xylene and water ofthe same volume are added into a test tube to form astable phase interface Unmodified and modified

particles are, respectively, dispersed in the xylene– water system and stirred. After the mixture has

stabilized, the hydrophobic characteristics can bequalitatively evaluated by inspecting the state of thefloating/sinking of samples at the interface. Thecriterion of hydrophobic index is shown in table 2.

Results and Discussion

Fe2O3/TS-1 catalysts were characterized byX-ray diffraction technique. The XRD patterns wereshowed in Figure 1. Characteristic diffraction lines ofTS-1 is observed at 2θ = 7,94; 8; 23.08; 23.62; 23.88;23.92°. The peak at 2θ around 24º is observed for the

change of crystal symmetry from monoclinicsymmetry, which is symmetry of silicalite-1, becomesorthorombic symmetry which is symmetry of TS-1.This Phenomenon indicates that titanium atom isalready in the framework structure of TS-1 [18]. X-ray diffraction pattern of Fe2O3/TS-1 with various ofFe2O3 loading showed similar pattern with parent TS-1 sample. This finding indicated that the MFIstructure of TS-1 is not collapsed after impregnationof Fe2O3. Therefore, the low content of Fe2O3 (up to

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4% wt) on TS-1 catalyst surface doesn't change the initial structure framework of TS-1.

Figure 1. X-ray Diffractogram Pattern of TS-1 dan Fe2O3/TS-1

The XRD peak intensity of the samples at 2θ around23.00o is decrease along with the increasing of Fe2O3 loading in TS-1 (table 1). This result indicates that

Fe2O3 were already located on the TS-1 surface.

Table 1. Crystallinity of Fe2O3/TS-1 and TS-1

Samples CodeIntensity at2θ = 23.00o,

CpsTS-1 (2θ = 23.060o)

0,5Fe2O3/TS-1 (2θ = 23.167o)

1Fe2O3/TS-1 (2θ = 23.183o)

2Fe2O3/TS-1 (2θ = 23.138o)

4Fe2O3/TS-1 (2θ = 23.302o)

32883030296423492332

Infrared spectra of the samples are shown infig 2. Catalyst samples of TS-1 and Fe2O3/TS-1

shows absorption band at wavenumber around 1100,800, and 450 cm-1, which is vibration mode of SiO4 orAlO4 tetrahedral. Absorption band at wavenumber

around 1100 cm

-1

is unsymmetrical vibration mode ofSi-O-Si, and absorption band at wavenumber around800 cm-1 is its symmetrical vibration mode.Absorption band at wavenumber around 1230 and547 cm-1 is characteristic for tetrahedral structure inframework zeolite MFI [19]. Absorption band atwavenumber around 970 cm-1 is characteristic of TS-1 which is vibration mode of stretching Si-O fromunit [SiO4] which tied at atom Ti

4+ with tetrahedralcoordination in TS-1 framework. Absorption band atthis wavenumber is evidence that titanium atom hasalready stayed inside the structure of catalystframework [20].

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Figure 2. IR Spectra of TS-1 and Fe2O3/TS-1 samples with various loading

4 Fe2O3/TS-1

2 Fe2O3/TS-1

%T1 Fe2O3/TS-1

0.5 Fe2O3/TS-1

1 1 0 0 c m

- 1

TS1

9 7 0 c m - 1

silicalite

8 0 0 c m - 1

5 4 7 c m - 1

4 5 0 c m - 1

1 2 3 0 c m - 1

1400 1300 1200 1100 4001000 900 800 700 600 500

wavenumber, cm-1

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Table 2. Hydrophilicity Character Definition [21]Hydrophilic Samples sink into water quickly and completely

Hydrophilic Samples sink into water not so quickly, but completely

Hydrophilic Samples float at first and then sink into water slowly and completelyPartially Hydrophilic Samples float at first and then sink into water slowly. Part of the powder

floats on surface of water and, after agitation, sinks into watercompletely

Partially Hydrophobic Samples float on the surface of water. After a long time agitation, part ofthe powder still floats on the surface of water

Completely Hydrophobic Samples float on the surface of water even with strong agitation for along time

Table 3. Hydrophobicity Character of TS-1 and Fe2O3/TS-1 SamplesSample Index Character Water sinks time

(seconds)

TS-1 5 Partially Hydrophobic 1 : 08.4

0,5Fe2O3/TS-1 5 Partially Hydrophobic 1 : 02.4

1Fe2O3/TS-1 5 Partially Hydrophobic 0 : 47.2



Catalyst hydrophilicity character analysis iscarried out by catalyst samples dispersion method inthe mixture of water and organic phase (xylene).

The results of hydrophobic tests are shownin Table 3. All samples seem to show similar

behavior during the hydrophilicity test, this indicatesthat the addition of metal oxide on TS-1 surfacedidn’t give too much effect in TS-1 catalyst

properties, which is partially hydrophobic. Nevertheless, the addition of metal oxide on TS-1

surface makes Fe2O3/TS-1 catalyst become muchmore hydrophilic than TS-1 catalyst. It can be seen intable 3 that the higher Fe2O3 loading in TS-1 catalystresulted in the faster sinks into water. From Table 3,it can be concluded that there is the increasing of thecatalyst hydrophilicity character along with theincreasing of metal oxide Fe2O3 content at TS-1catalyst surface.

Conclusion

1. Catalyst TS-1, 0,5Fe2O3/TS-1, 1Fe2O3/TS-1, 2Fe2O3/TS-1, and 4Fe2O3/TS-1 has beensuccessfully synthesized

2. Catalyst 0,5Fe2O3/TS-1, 1Fe2O3/TS-1,2Fe2O3/TS-1, and 4Fe2O3/TS-1 still haveorthorombic structure MFI type which ischaracteristic of TS-1 catalyst.

3. Catalyst hydrophilicity character increasessuccessively from TS-1, 0.5Fe2O3/TS-1,1%Fe2O3/TS-1, 2Fe2O3/TS-1, and4Fe2O3/TS-1.

Acknowledgement

We gratefully acknowledge funding from theDirectorate General of Higher Education, Indonesia,

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References

[1] Tang, H., Ren, Y., Yue, B., Yan, S., He, H.(2006), “Cu-incorporated Mesoporous

Materials : Synthesis, Characterization andCatalytic Activity in Phenol Hydroxylation”, Journal of Molecular Catalysis A :

Chemical , Vol. 260, hal. 121-127.[2] Liu, H., Lu, G., Yanglong Guo, Yun Guo, dan

Wang, J. (2006), “Chemical Kinetics ofHydroxylation of Phenol Catalyzed by TS-1/Diatomite in Fixed-Bed Reactor”,Chemical Engineering Journal , Vol. 116,hal. 179–186.

[3] Choi, J., Yoon, S., Jang, S., Ahn, W. (2006),“Phenol Hydroxylation Using Fe-MCM-41Catalysts”, Catalysis Today, Vol. 111, hal.

280-287.[4] Liu, X., Wang, X., Guo, X., Li, G. (2004), “Effectof Solvent on the Propylene Epoxidationover TS-1 Catalyst”, Catalysis Today, Vol.93-95, hal. 505-509.

[5] Kurian, M., Sugunan, S. (2006), “Wet PeroxideOxidation of Phenol Over Mixed PillaredMontmorillonites”, Chemical Engineering

Journal , Vol. 115, hal. 39-146.[6] Vayssilov, G. N. dan van Santeny, R. A. (1998),

“Catalytic Activity of Titanium Silicalites— a DFT Study”, Journal of Catalysis, Vol.175, hal. 170–174.

[7] Sun, J., Meng, X., Shi, Y., Wang, R., Feng, S.,

Jiang, D., Xu, R., Xiao (2000), “A NovelCatalyst of Cu–Bi–V–O Complex in PhenolHydroxylation with Hydrogen Peroxide”,

Journal of Catalysis, Vol. 193, hal. 199–206.[8] Wilkenhöner, U., Langhendries, G., van Laar, F.,

Baron, G. V., Gammon, D. W., Jacobs, P.A., dan van Steen, E. (2001), “Influence ofPore and Crystalline Titanosilicates onPhenol Hydroxylation in DifferentSolvents”, Journal of Catalysis, Vol. 203,hal. 201-212.

[9] Bonino, F., Damin, A., Ricchiardi, G., Ricci, M.,Spano`, G., D’Aloisio, R., Zecchina, A.,

Lamberti, C., Prestipino, C., dan Bordiga, S.(2004), “Ti-Peroxo Species in The TS-1/H2O2/H2O System”, Journal of PhysicalChemistry B, Vol. 108, hal. 3573-3583.

[10] Armaroli, T., Bevilacqua, M., Trombetta, M.,Milella, F., Alejandre, A. G., Ramirez, J.,

Notari, B., Willey, R. J., dan Busca, G.(2001), “A Study of The External andInternal Sites of MFI-Type ZeoliticMaterials through The FTIR Investigation of

The Adsorption of Nitriles”, AppliedCatalysis A : General , Vol. 216, hal. 59–71.

[11] Nur, H., Prasetyoko, D., Ramli, Z., Endud, S.(2004), “Sulfation: A simple Method to

enhance the Catalytic Activity of TS-1 inEpoxidation of 1-octene with AqueousHydrogen Peroxide”, CatalysisCommunications . Vol.5, hal. 725–728.

[12] Prasetyoko, D., Ramli, Z., Endud, S., Nur, H.(2005), “Enhancement of Catalytic Activityof Titanosilicalite-1–Sulfated ZirconiaCombination Towards Epoxidation of 1-Octene With Aqueous Hydrogen Peroxide”,

Reaction Kinetics Catalysis Letter , Vol. 86,hal. 83-89.

[13] Ray, S., Mapolie, S. F., Darkwa, J. (2007),“Catalytic Hydroxylation of Phenol usingImmobilized Late Transition MetalSalicylaldimine Complexes”, Journal of

Molecular Catalysis A : Chemical , Vol. 267,hal. 143-148.

[14] Indrayani Suci, (2008), Aktivitas Katalitik MoO3/TS-1 pada Reaksi Hidroksilasi Fenol

menggunakan H 2O2, Tesis M.Si, JurusanKimia FMIPA Institut Teknologi Sepuluh

Nopember, Surabaya.[15] Taramasso, M., Perego, G. and Notari, B.

(1983), “Preparation of Porous CrystallineSynthetic Material Comprised of Silicon andTitanium Oxides”. (U. S. Patents No.4,410,501).

[16] Choudhary, V. R., Jana, S. K., Mamman, A. S.(2002), “Benzylation of Benzene by BenzylChloride over Fe-modified ZSM-5 and H-β Zeolites and Fe2O3 or FeCl3 deposited onMicro-, Meso-, and Macro-porousSupports”, Microporous and Mesoporous

Materials, Vol. 56, hal. 65-71.[17] Hattori, H., Ogawa, T., Jones, F., Knudson, C.,

Willson, W., Rindt, J., Mitchell, M.,Stenberg, V., Radonovich, L., Janikowski, S.(1985), “Reduction Activities of Fe2O3/SiO2 Catalysts with Hydrogen Sulphide andHydrogen”, Fuel , Vol. 65, hal. 780-785.

[18] Li, Y.G., Lee, Y.M., Porter, J.F. (2002), “TheSynthesis and Caracterization of TitaniumSilicalite-1”, Kluwer Academic Publishers,hal. 0022-2461.

[19] Drago, R. S., Dias, S. C., McGilvray, J. M.,Mateus, A. L. M. L. (1998), “Acidity andHydrophobicity of TS-1”, Journal of

Physical Chemistry, Vol. 102, hal. 1508-1514.

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[20] Li, G., Wang, X., Guo, X.,Liu, S., Zhao, Q., Bao,X., Lin, L. (2001), “Titanium Species inTitanium Silicalite TS-1 Prepared ByHydrothermal Method”, Materials

Chemistry and Physics, Vol. 71, hal. 195-201.[21] Wang, Z., Wang, T., Wang, Z., Jin, Y. (2004),

“Organic Modification of Ultrafine Particlesusing Carbon-dioxide as the Solvent”,

Journal of Powder Technology, Vol. 139,hal. 148-155.

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New Mixed Ligands Complexes of Zinc(II), Cadmium(II) and Bismuth(III)

With Dithiocarbamates and 2,2’-Bipyridyl

Normah Awang1, Ibrahim Baba

2 and Bohari Mohd Yamin

2

1 Environmental Health Programme, Faculty of Allied Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja

Muda Abdul Aziz, 50300 Kuala Lumpur

[email protected]+60326878034

2 School of Chemical Sciences and Food Technology, Faculty Science and Technology, Universiti Kebangsaan

Malaysia, 43600 Bangi, Selangor

Abstract

A new series of zinc(II), cadmium(II) and bismuth(III) complexes with mixed ligands, dithiocarbamate and 2,2’-

bipyridyl were successfully synthesized using “in situ” method. Microelemental analysis data of the complexes are

in agreement with the general formula, M[S2CNR’R”]n bipy (M = Zn, Cd & Bi; R = s-butyl, R’ = propyl; R = benzyl, i-propyl; bipy = 2,2’-bipyridyl). Infrared spectra of the complexes showed that the thioureide ν(C N)

band is in the regions 1438 – 1453 cm-1

. The unsplitting band of ν(C-S) in the region 930 – 1000 cm-1

indicates the

bidentate nature of the chelated dithiocarbamate ligands. The13

C NMR chemical shift of the carbon atom of the N-

CS2

group appeared in the range of 201.67 – 208.27 ppm. The crystal structure of zinc(II)

benzylisopropyldithiocarbamate(2,2’-bipyridyl) supports the elemental and spectroscopic data in which twodithiocarbamates and one bipy ligands chelated to the central Zn atom in bidentate manner in a distortedoctahedron environment.

Keywords: dithiocarbamate; chloroform; IR spectra; biological activity

Introduction

For several years considerable attention has been paidto dithiocarbamate compounds. Firstly, their

biological effects have been researched, including

antialkylation, anti-HIV properties [1] and antitumor

activity against leucemic cells [2]. Some

dithiocarbamate complexes also have some practicalapplications. For example, they are used in

agriculture as fungiside and pesticide [3].

The 1:1 adducts of zinc and cadmiumdialkyldithiocarbamates with 2,2’-bipyridyl have

been reported and some of these complexes are very

active accelerators for the vulcanization of rubber and

low temperature vulcanization of latex [4]. Thecrystal structure of Zn[S2CN(C2H5)2]2(2,2’-bipy) has

been reported [5].

In spite of the fact that many

dithiocarbamate compounds with different transition

metals are described in the chemical literature, wehave only considered Zn(II), Cd(II) and Bi(III)

coordination compounds with non-symmetrical

dithiocarbamates with the general formula

M[S2CNR’R”]

n bipy. (M = Zn, Cd & Bi; R = s-butyl,

R’ = propyl; R’ = benzyl, R”i-propyl; bipy = 2,2’-

bipyridyl). So far, no information on complexes of

this type with the sec-butylpropyl and

benzylisopropyldithiocarbamate ligands were found

in the literature.

Materials and Methods

Reagents

All the reagents and solvents employed were

commercially available analytical grade materials and

were used as supplied, without further purification. N - benzylisopropylamine, 2,2’-bipyridyl and ethanol

(95%) were obtained from Fluka Chemicals. Carbon

disulphide and methanol (99.5%) from AjaxChemical Ltd. Bismuth(III) chloride was obtained

from Hayashi Pure Chemical Indsutries Ltd.

Cadmium(II) dichloride monohydrate, chloroform

and zinc(II) chloride were purchased from Merck.

Physical and spectroscopic measurement

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Elemental analyses were performed on a Fision EA

1108 CHN Elemental Analyser. Melting points were

determind on a Electrothermal IA 9100 apparatus.1

H

and13

C NMR spectra were recorded in CDCl3

solution on a Joel JNM – LA400 spectrometer with

chemical shifts relative to tetrametylsilane. IR spectra

were obtained as KBr pellets on a Perkin Elmer

FTIR Model GX spectrophotometer in the frequency

range 4000 – 500 cm-1

and 500 cm-1

- 200 cm-1

.

Synthesis of dithiocarbamate complexes

The mixed-ligand complexes were prepared by

adding equimolar of metal dithiocarbamate

compound (zinc(II), cadmium(II) and bismuth(III))

and 2,2’-bipyridyl in the mixture of ethanol andchloroform solutions. The method used to prepare themetal dithiocarbamate compounds were synthesized

by a method reported earlier [6]. The resulting

mixture was stirred for one hour and the solvent was

allowed to evaporate at room temperature. After two

days, the crystals separated out and washed with coldethanol.

Results And Discussion

The Mn+[S2CNR’R”]m(bipy) complexes (n = 2, m = 2;

n = 3, m = 3; R’ = s-C4H9, R” = CH3; R’ = C7H7, i-

C3H7; bipy = 2,2’-bipyridyl) were prepared via a

straightforward process involving only two steps. Allthe compounds were non-hgroscopic and stable in air.

They were insoluble or sparingly soluble in most

common organic solvents and very soluble in

chloroform. The results of elemental analyses (Table

1) are in good agreement with those required by the proposed formulae. The formation of these complexes

may proceed according to the following equationgiven below.

M[S2CNR’R”]n + C10H8 N2 → M[S2CNR’R”]n(C10H8 N2)

M = Bi(III), Cd(II), Zn(II); n = 2 or 3; R’ = C7H7, R”

= i-C3H7; R’ = s-C4H9, R” = C3H7

Table 1. Physical and elemental analysis data of mixed-ligand complexes

% Found (calcd)Compound Colour Melting

point

(°C)

C H N S M

Zn[S2CN(C7H7)(iC3H7)]2 bipy

(compound 1)

Yellow 165.9-

166.5

55.80

(57.37)

5.03

(5.38)

8.36

(8.37)

20.23

(19.12)

11.32

(9.77)Cd[S2CN(C7H7)(iC3H7)]2 bipy(compound 2)

Yellow 223.2-224.4

52.30(53.60)

4.65(5.02)

7.51(7.82)

17.34(17.87)

14.07(15.69)

Zn[S2CN( sC4H9)(C3H7)]2bipy

(compound 3)

Yellow 133.8-

134.3

52.83

(51.88)

7.27

(6.65)

9.55

(9.31)

22.18

(21.28)

8.73

(10.87)

Cd[S2CN( sC4H9)(C3H7)]2bipy

(compound 4)

Yellow 194.8-

195.3

47.68

(48.12)

6.65

(6.17)

9.71

(8.64)

19.09

(19.74)

16.00

(17.33)

Bi[S2CN( sC4H9)(C3H7)]3 bipy(compound 5)

Orange 115.8-116.5

43.84(43.64)

6.76(5.99)

8.57(7.49)

21.80(20.54)

20.87(22.35)

The infrared spectra of the title compounds

and important characteristic absorption bands, along

with their proposed assignments are summarized inTable 2. The IR spectra of the compounds are very

similat to each other, except some slight shifts and

intensity change of a few vibration bands caused by

different metal ions, which indicate that thecompounds have similar structures. Coordination in

the mixed-ligand mainly affected the C-N and C-S

stretching bands [7].

Table 2. The important infrared absorption bands ofcompound 1-5 (cm-1)

Compound ν(C N) ν(N- ν(C S) ν(M-

1 1440 1174 967 386

2 1438 1171 970 387

3 1441 1196 967 376

4 1439 1194 957 386

5 1453 1189 951 358

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The selected 1H NMR peaks for compounds1-5 are showned in Table 3. The aromatic proton

signals for 2,2’-bipyridyl in compounds 1-5 were

observed in the range 7.33 – 9.01 ppm. This signal

was not observed in the

1

H NMR spectra for metaldithiocarbamate compounds. Two proton signalsfrom 2,2’-bipyridyl in compounds 1-4 have shifted

which one signal to downfield and the other onesignal to upfield. These shifts indicate that 2,2’-

bipyridyl has been coordinated to the metal atom. The

IR spectra data combined with these data showed that

the 2,2’-bipyridyl has coordinated to the metal atomin all of these compounds.

Table 3. The selected 1H and 13C NMR data (δ, ppm) for compounds 1-5

Compound Formula 1H NMR

(bipy)

13C NMR

(N13CS2)

2,2’-bipyridyl (C10H8 N2) 8.70 (d), 8.41 (d), 7.83 (t),7.33 (t)

-

1 Zn[S2CN(C7H7)(iC3H7)]2 bipy 8.95 (d), 8.26 (d), 7.86 (t),

7.33 (t)

206.62

2 Cd[S2CN(C7H7)(iC3H7)]2 bipy 9.01 (d), 8.19 (d), 7.95 (t),

7.48(t)

208.27

3 Zn[S2CN( sC4H9)(C3H7)]2bipy 8.82 (d), 8.35 (d), 7.85 (t),7.35 (t)

203.88

4 Cd[S2CN( sC4H9)(C3H7)]2bipy 8.95 (d), 8.26 (d), 7.86 (t),

7.33 (t)

205.93

5 Bi[S2CN( sC4H9)(C3H7)]3 bipy 8.70 (d), 8.40 (d), 7.84 (t),

7.33 (t)

201.67

The most important signal in the 13C NMR

spectra was the chemical shift for N13CS2 carbon. The

N13CS2 chemical shifts for compounds 1-5 were

observed in the range 201.67-208.27 ppm which notobserved in the 13C NMR spectra for 2,2’-bipyridyl

compund. The N13

CS2 chemical shift for compounds1 and 2 dropped slightly to downfield compared tothe parent compounds (205.08 and 205.77 ppm

respectively). The high values of N13CS2 chemical

shifts could be explainded by an increase of π bondorder in the whole NCS2 moiety [8] which means that

the chelation of 2,2’-bipyridyl to the metal atoms has

promoted the delocalization of the unshared electron pair in the nitrogen atoms in the dithiocarbamate

groups.

Suitable crystal for X-ray crystallographic

studies of compound 2 were obtained by slowevaporation of a chloroform:ethanol mixture at room

temperature. The dithiocarbamate ligands and 2,2’- bipyridyl are bidentically chelated to the zinc atomand the coordination geometry around zinc was

distorted octahedral.

Conclusion

The elemental, spectroscopic and crystallographic

data showed that the new mixed-ligand complexes

have been successfully synthesized. The

dithiocarbamate ligands and 2,2’-bipyridyl were

chelated to the metal atom to form the

hexacoordinated mixed-ligand complexes. The

crystallographic study of compound 2 showed that both of the dithocarbamate ligands and 2,2’-bipyridyl

were bidentically chelated to the zinc atom.

Acknowledgement

The authors gratefully acknowledge the research

grant provided by The Malaysian Government (IRPA

09-02-02-0048-EA144) and Universiti Kebangsaan

Malaysia for financial support. Technical support

from laboratory assistants of Faculty Science andTechnology, Universiti Kebangsaan Malaysia is

gratefully acknowledged.

References

[1] Hersh, E.M., Brewton,G., Abrams,D., Bartlett,J.,

Galpin,J., Gill,P., Gorter,R., Gottlieb,M.,

Jonikas,J.J., Landesman,S., Levine,A.,Marcel,A., Petersen,E.A., Whiteside,M.,

Zahradnik,J., Negron,C., Boutitie,F., Caraux,J.,Dupuy,J. & Salmi,R. 1991. Ditiocarb sodium

(diethyldithiocarbamate) therapy in patients with

symptomatic HIV infection and AIDS: A

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randomized, double-blind, placebo-controled,multicenter study. J. Am. Med. Assoc.,

265:1538–1544.

[2] Mital, R., Jain, N. & Srivastava, T.S. 1989.

Synthesis, characterization and cytotoxic studiesof diamine and diimine palladium(II) complexesof diethyldithiocarbamate and binding of these

and analogous platinum(II) complexes with

DNA. Inorganica Chimica Acta, 166(1):135-140.

[3] Montgomery, J.H. 1993. Agrochemical DeskReference Environmental Data, Lewis Publisher,

Michigan.

[4] Bateman, L. 1963. The chemistry and physics ofrubber like substance, Maclaren, London.

[

4628 didik prasetyoko 08. inorganic chemistry

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