proceso de la irradiación efecto quimico.pdf

7/28/2019 Proceso de la irradiacin efecto quimico.pdf

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Radiation ProcessingChemical Effects


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Reactions ofHydrated ElectronMajor Reactions of e-aq

H201. e-aq + N20 N2 + {)H

Used to detect/estimate e-aq

and to increase OH yield2. e-aq + O2 -. .. H02Used to produce 02-' prevalent in systems open to air3. e-aq + C6Hsi C6Hsl + r

Dissociative electron capture by halogenated organicscan be used to detect and estimate e-aq

4. e-aq + Fe3+ Fe2+e-aq + N03- NOl-

Reactions with cations and many anions are known tooccur


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Reactions ofHydrated Electrons (contd)5. Reduces carbonyls to hydroxy derivativesseveral

steps6. Decreases aromaticity

H

stepsseveral

- - - - - - I . ~ : r I~ ~ .....~Dihydronaphthaleneaphthalene

7. Reacts with cellular constituents (e.g. amino acids)e-aq + NH3+CHRCOO- - NH3 + CHRCOO- NH2 + RCHCOOH- .. H + NH2CHRCOO-


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Reactions of OHThe major types of reactions are

1. Addition to double bondsOHI .>C=C< + OH >C - C C =C < + H ~ > C - C C =C > C - C


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Radiolysis ofCyclohexaneo C6H12Products

H2c-CSH10(c-CSH11hCH=CH(CH2hCH2c-CSH7-CH 3C-CSH11-(CH2)4CH=CH2n-CSH14unidentified C12C-CSH11-C2Hs

Initial Yield(molecules/100 eV)5.6 + 0.13.2 0.21.76 + 0.050.40 + 0.050.15 0.010.12 + 0.020.08 + 0.02

I 'J 0.05I 'J 0.04


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Gamma Radiolysis ofLiquid Cyclohexanein the Presence ofOxygenG (Product)

Product Evacuated Sample in 02Sample (2 mol m-3)

1-Hexene 0.5 0.26Hexane 0.1


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Products

Radiolysis ofBenzene~ C6H6

G(molecules/100 eV)HydrogenEthyleneAcetylene1,4-Cyclohexadiene1,3-CyclohexadienePhenyl-2,4-CyclohexadienePhenyl-2,5-CyclohexadieneBiphenylCe units incorporatedin polymers

0.0390.0220.0200.0210.0080.0210.0450.0650.8


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Radiolysis ofChlorobenzeneYields ofMajor Productsa

Product G(Product)Hydrogen 0.01Hydrochloric acid 0.25Benzene 2.91Biphenyl 0.12Dichlorobenzene 0.36Chloro-biphenyl 0.90a Dose, 208/kGy (Spinks and Woods, 1990)


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'Y -Radiolysis ofLiquid Acetoneand Methyl Acetate at - 22-28C, G(Products)Product Acetone Methyl Acetate(CH3COCH3) (CH3COOCH3)HydrogenCarbon MonoxideCarbon DioxideMethaneEthaneAcetaldehydeDimethyl EtherAcetic AcidBiacetylMethyl Ethyl Ketone2-Propanol(CH3COCH2)2CH 3COCH2COCH3

0.500.73-1.740.240.09-0.310.280.180.090.270.11

0.761.640.962.030.340.15---


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Conclusions- Understanding of the detailed chemicalprocesses occurring on irradiation has helpeddevelop many of the commercial applicationsof radiation processing, e.g., curing ofcoatings, crosslinking of polyethylene, andpurification of water in the presence of ozone-Continuing effort in this area is needed toimprove current, and develop new, chemicaleffect based processes

proceso de la irradiación efecto quimico.pdf

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