SEPTEhTBER, 1933 INDUSTRIAL -4SD ENGINEERING CHEMISTRY 1069

Isolation of Intermediate Ester Propylene was contacted in a rotating autoclave with 90

per cent orthophosphoric acid at 125" C. and initial pressure of 10 atmospheres. The reaction product was a homogene- ous liquid which presumably contained isopropyl phosphate. When this liquid was heated a t 150" C. in the same apparatus, two layers were formed. The upper layer consisted of propyl- ene polymer, and the lower layer was phosphoric acid which was capable of polymerizing additional propylene.

A similar experiment was made with ethylene, which was heated with 90 per cent acid a t 200" C. under an initial pressure of GO atmospheres. The reaction product was a homogeneous liquid. A sample of this liquid was neutralized by barium hydroxide solution, and the resulting barium salt was analyzed for barium ((weighed as barium sulfate) and for phosphorus (weighed as magnesium pyrophosphate). The analytical figures agreed fairly well with those for the barium salt of monoethyl phosphoric acid.

Alrau~srs. Calculated for C2HrBaPOa: barium, 52.5; phos- phorus, 11.9.

T h e n the ester was heated in the same apparatus a t 330" C., two layers were formed, an upper polymer layer and a lower phosphoric acid layer.

Accelerating Effect of n-Butylenes upon Polymeri- zation of Propylene

Pure propylene was polymerized by 100 per cent phosphoric acid a t 135" C. and atmospheric pressure, but its rate of polymerization was accelerated by the presence of butylenes or by merely passing them through the acid for a short time. For example, propylene was polymerized to the extent of 13 per cent over a period of 3 hours by a sample of fresh acid. At the end of this time the propylene was replaced by a- butylene which was passed through the acid for 1 hour. Finally, propylene was again passed through the acid under

Found: barium, 53.3; phosphorus, 12.1.

, I I od 10 NJ 30 LA- A /L2=

FIGIJRE 2. PODBIELNIAK DISTILLATION OF PROPYLENE- BUTYLENE POLYMER

the same operating conditions as those used in the first pro- pylene period. The propylene was absorbed to the extent of 39 per cent over a period of 6 hours after this activation. ISO- and P-but#ylenes were found to produce the same effect as a- butylene.

Mixed Polymer Obtained by Polymerization of Olefin Mixture

Not only does propylene polymerize more readily in the presence of butylene, but also the liquid polymer produced from a mixture of propylene and butylene is different than that obtained from propylene or biutplene individually. A mixture of propylene and butylenes (20 per cent of propylene, 10 per cent of n-butylenes, 5 per cent of isobutylene, 65 per cent of propane and butanes) was polymerized at 200" C. and

10 atmospheres gage pressure. These were conditions under which propylene is able to polymerize alone, without the ac- tivating effect of the butylenes. Distillation data of the liquid polymer are presented in Figure 2. In spite of the fact that the gas mixture contained a high percentage of propyl- ene, the product contained only a small amount of nonylene (i. e., fraction boiling a t 130" to 140" C.) which was the chief product when propylene was polymerized by itself. About 50 per cent of the polymer boiled a t 80" to 110" C., apparently consisting of seven- and eight-carbon olefins.

Acknowledgment The author is indebted to B. B. Corson, A. Yon Grosse,

V. Komarewsky, H. Pines, and R. E. Schaad for the experi- mental work, and to I. D. Kurbatov and R. C. Wackher for the analytical data.

11. Butylenes V. N. IPATIEFF AND B. B. CORSOK

The isomeric butylenes are polymerized by orthophosphoric acid at atmospheric pressure and relatively low temperatures to liquid polymers. These polymers are monoolefins. Isobutylene polymerizes the most readily, and a-butylene the least. The presence of isobutylene accelerates the polymerization of the n-butylenes.

UTYLENES are polymerized by phos- phoric acid and the mechanism is assumed B to be the same as that of propylene, as

described in Part I. The speed of polymerization of the butylenes is greater than that of propylene, the rates increas- ing in the following order: propylene, a-butylene, @-butylene, isobutylene.

The liquid polymerization products of the isomeric butyl- enes are similar in physical and chemical properties. They are mixtures of liquid monoolefins. The evidence for their chemical nature is the same as that for the propylene poly- mers-namely, they are practically 100 per cent soluble in 96 per cent sulfuric acid a t 0" C., they are converted into paraf- fins by catalytic hydrogenation, their bromine numbers agree with that calculated for monoolefins, and their carbon- hydrogen ratios correspond to that of C,H*,.

Gentle polymerizing conditions favor the production of simple polymer mixtures, whereas more drastic conditions yield more complicated mixtures. For example, the iso- butylene polymer produced a t 30" C. contained only two compounds, whereas polymer made a t 130" C. contained seven compounds.

The presence of isobutylene accelerates the polymerization of the n-butylenes. A mixture of iso- and n-butylenes poly- merizes a t lower temperature and with lower acid concen- tration than the n-butylenes alone.

Preparation of Butylenes The butylenes were prepared in a semi-automatic glass

apparatus (1) by catalytic dehydration (8) of the correspond- ing alcohols over activated alumina a t 375" to 425" C. The a-butylene (prepared from n-butyl alcohol) and the isobutyl- ene (prepared from tertiary or isobutyl alcohol) mere pure,

1070 INDUSTRIAL AND ENGINEERING CHEMISTRY VOL. 27, NO. 9

FIGURE 1. COPPER STIRRING AGITATOR

GAS /N

FIGURE 2. GLASS STIRRING AGITATOR

but the “/?-butylene” (prepared from secondary butyl alcohol) was approximately a 50-50 mixture of a- and @-butylenes (4).

Polymerization Apparatus and Procedure The butylenes were polymerized by liquid phosphoric acid in

copper (Figure 1) and glass (Figure 2) contactors which were de- signed to give effective liquid-gas contact. The perforated baffle plates of the copper apparatus and the reentrant shoulders of the glass flask were instrumental in attaining this end. The acid charge was drawn into the ap aratus by applying suction to the side arm of the condenser, anf the contents were discharged by the application of pressure.

The different butylenes were passed through the acid at definite rates and the gas absorption was measured. The unabsorbed gas was condensed and subsequently recirculated. The liquid polymer was discharged from time to time without dismantling the equipment, leaving the hosphoric acid in the apparatus until the end of the experiment Ysometimes for 15 days of continuous operation).

One hundred per cent phosphoric acid was found to be a stronger polymerizing agent than 95, 89, and 85 per cent acids. The rate of polymerization depended upon the rate at which the olefin was passed through the acid, as illustrated by the following data on a-butylene; the temperature was 130’ C., the pressure was atmospheric, and the catalyst was 100 cc. of 100 per cent orthophosphoric acid:

Gas Rate , Li terdHour

6 . 5 1 0 . 7 1 5 . 0 2 1 . 2 3 5 . 6 4 6 . 1

Per Cent Polymerized

92 92 87 67 46 37

Litera Polymerized

per Hour 6 . 0 9 . 9

1 3 . 0 1 4 . 2 1 6 . 4 1 7 . 1

Catalytic Life of Phosphoric Acid

The catalytic effectiveness of liquid phosphoric acid is shown by the following data on a-butylene:

Liquid polymer produced, cc., (grams) Orthophosphoric acid (loo%), cc. (grams) Inlet gas rate, liters/hour 13.5 Outlet gas rate, liters/hour 5 .0

10300 (7962) 100 ( 187)

The experimental conditions were 130’ C. and atmospheric pressure. Calculations show that 1 molecule of phosphoric acid polymerized 74.5 molecules of a-butylene, which is a conservative estimate since there was some mechanical loss of acid during the experiment. Moreover, this value does

not represent the total catalytic life since the acid was still active when the run was discontinued.

Relative Rates of Polymerization of Butylenes and of Propylene

The relative rates of polymerization (Figure 3) were de- termined a t several temperatures and gas rates. Fresh acid (100 cc. of 100 per cent orthophosphoric acid) was used with each olefin. Isobutylene was the most reactive of the olefins studied and propylene the least. As the “@-butylene” con- tained about equal parts of a- and &butylenes, the true ac- tivity of @-butylene would be greater than is shown in the curve.

FIGURE 3. RELATIVE RATES OF POLYMERI- ZATION OF ISOMERIC BUTYLENES BY 100 PER

CENT PHOSPHORIC ACID

Inasmuch as the butylenes are isomerized (3) in the pres- ence of phosphoric acid, there is no guarantee as to the re- liability of the relative rates of polymerization reported. Although the starting material was pure, the material which was actually polymerized might have been a mixture of iso- meric butylenes, the relative proportions of which would de- pend upon the experimental conditions.

Characteristics of Butylene Polymers iMade with 100 Per Cent Orthophosphoric Acid

The liquid polymers from the individual butylenes were similar in physical and chemical prpperties. Table I pre- sents certain physical properties of the a-, “@-”, and isobutyl- ene polymers (Figure 4).

SEPTEMBER, 1

FIGURE 4. PODBIELNI.4K DISTILLATION CURVES OF BUTYLENE POLYMERS

1071

TABLE I. PROPERTIES OF BUTYLENE POLYMERS MADE AT 130' C. Fraction -Bromine KO.- F ~ ~ -

No. B. P. Volume d:' ny Found Calcd. mula

a-Butylene Polymer = c . 70

0 1 2 3 4 5 6 7 8 9

10 11 12

0-50 50-102

102-110 110-112 112-128 128-148 148-158 158-174 174-175 175-190 190-192 192-213 213-230

4 2

1 :3 7 :I 5 6 6

1,5 13 7

14 7

0 : 702 0 ,727 0.732 0.740 0 . 7 5 1 0.763

0:774 0.784 0 .801 . . . . . .

. . . . 1.4098 1.4160 1 ,4188 1,4252 1.4306 1.4330 1.4348 1.4390 1.4432 1.4510 . . . . . . . .

154 150 152 128 117 105 101 98 53 59 . . .

. . .

143

95

72

Analysis of fraction boiling a t 102-110' C.: Calcd. for C8Hl5: C , 85.7; H , 14.3; found: C, 85.3; H, 14.4.

0 1 2 3 4 5 6 7 8 9

10 11

0-102 102-103 103-113 113-134 134-140 140-148 148-170 170-174 174-184 184-193 193-206 206-242

6 9

11 3 5 B b

1 5 1; 13

8-Butvlene Polvmer . . .

0:727 0.734 0 . 7 4 0 0.748 0.756 0.764 0 .771

0 : 804 . . .

. . . . 1.4125 1. ,4125 1 ,4200 1 ,4285 1,4276 1,4300 1,4335 1.4375 1 .4410 1,4490 1,4535

139

93

69

143

55

7 2

Analysis of fraction boiling a t 103-113' C.: Calcd. for CsHie: C, 85.7; H ,

Analysis of fraction boiling a t 174-193" C.: Calcd. for C I Z H ~ ~ : C, 85.7; 14.3; found: C , 85.4; H,, ,14.4.

H, 14.3; found: ( 2 , 8 5 2 ; H, 14.2.

Isobutylene Polymer 0 0-42 2 . . _ 1 2 3 4 5 6 7 8 9

10 11 12 13 14 1 5

42-102 102-103 103-110 110-112 112-122 122-144 144-152 152-161 161-169 169-175 175-178 178--186 186-220 220-227 Above 227

1 14 4 i 5 7 7

14 6 5 4 1

1; J

. . . 0 : ; ' k

0.732 . . . , . .

0:760 . . .

0 , 7 6 4

1 4062

1.4166

1.4202

1.4270

1 .4320

1.4340

1 .4440

1.4543

140

147

118

82

91

48

143

95

72

Analysis of fraction boiling a t 104--108° C.: Calcd. for CsHts: C, 85.7: H,

Analysis of fraction boiling a t 171-177' ( 2 . : Calcd. for C12H24: C, 85.7; H.

AAalysis of f rh ion 'bo i l lng at'240--290D (2.: Calcd. for C15H32: C, 85 7 ; H,

14.3; found: C, 85,4; H,, l4.3.

14.3. found: C 85.6. H 14.2

14.3; found: C, 85.4; H. 14.3.

Isobutylene was polymerized a t four different tempera- tures, 30°, 60", loo", and 130" C. The polymer produced a t 30" C. was simpler than that produced a t 130" C. Podbiel- niak distillation data for isobutylene (Figure 4) indicated

that the former polymer contained only two individual eom- pounds, diisobutylene and triisobutylene, whereas the latter contained seven compounds. In other words, the higher the polymerization temperature, the more complex the product, either because of isomerization of the olefins or removal of the elements of phosphoric acid from the intermediate esters in different ways.

Accelerating Effect of Isobutylene upon Poly- merization of n-Butylenes

I n studying the polymerization of the isomeric butylenes, i t was noted that the less reactive a-butylene is converted into liquid polymer more rapidly in the presence of the more reactive isobutylene than when alone. For example, pure a-butylene was not polymerized by 89 per cent phosphoric acid a t 120" C. and atmospheric pressure, but a sample of commercial butylene (which contained 30 per cent of isobutyl- ene) was polymerized to the extent of 50 per cent under iden- tical experimental conditions.

Literature Cited (1) Corson, IND. EXQ. CHEM., Anal. Ed., 6, 297 (1!334). (2) Ipatieff, Ber., 36, 1990 (1903). (3) Ipatieff, Pines, and Schaad, J. Am. Chem. Soc., 56, 2696 (1934). (4) Pines, Ibid., 55, 3892 (1933).

RECEIVED May 18, 1935. The material presented under the title of this paper as part of the Symposium on the Chemistry of Gaseous Hydrocarbons a t the New York meeting of the Society was revised and rewritten as Par t s I and I1 as published here.

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