OH radical-induced oxidation of chlorobenzene in aqueous solution in the absence and presence of oxygen

被引:55
作者
Merga, G
Schuchmann, HP
Rao, BSM
vonSonntag, C
机构
[1] MAX PLANCK INST STRAHLENCHEM,D-45470 MULHEIM,GERMANY
[2] UNIV PUNE,DEPT CHEM,PUNE 411007,MAHARASHTRA,INDIA
来源
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2 | 1996年 / 06期
关键词
D O I
10.1039/p29960001097
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
The reaction of hydroxyl radicals, generated radiolytically in N,O-containing aqueous solutions [G((OH)-O-.) approximate to 5.8 x 10(-7) mol J(-1)], with chlorobenzene has been studied. In the presence of Fe(CN)(6)(3-) the major products (G values in units of 10(-7) mol J(-1) in parentheses) are 2-chlorophenol (2.5), 3-chlorophenol (1.25) and 4-chlorophenol (1.75), Pulse radiolysis with conductometric detection (in the absence of the oxidant) shows that prompt HCl formation (which occurs upon (OH)-O-. radical addition at the ipso-position) is only a very minor process (0.03), and it is concluded that (OH)-O-. radical addition to the ortho:meta:para:ipso positions occurs in a proportion of 1:0.5:0.7: < 0.01, i.e. there is a noticeable preference of attack at the pava and ortho positions and a considerable steric, hindrance of the addition to the ipso position, In the absence of the oxidant, the yield of the chlorophenols is low [G(total chlorophenols) = 0.4 x 10(-7) mol J(-1)] and dimeric products [bis(hydroxychlorocyclohexadienyls)] predominate, Most of these primary dimers are unstable and rearomatize under dehydration, which can be promoted by heating at pH 1, to various dichlorobiphenyl, chlorohydroxybiphenyl and dihydroxybiphenyl isomers. In the presence of O-2, the chlrohydroxycyclohexadienyl radicals are (reversibly) converted into the corresponding peroxyl radicals (k(forward) = 2.6 x 10(8) dm(3) mol(-1) s(-1); k(reverse)= 5.5 x 10(4) s(-1)). Out of this equilibrium two reactions occur (k(product formation) = 1.1 x 10(3) s(-1)): HO2-elimination leading to the three isomers of chlorophenol [G(chlorophenol total) = 2.1 x 10(-7) mol J(-1)] and formation of endo-peroxidic structures which in turn are converted into peroxyl radicals and subsequently undergo fragmentation. Most of these products, which number in excess of 30 by GC analysis, are free of chlorine [G(chloride ion) = 3.3 x 10(-7) mol J(-1)], apart from a few which contain the vinyl chloride function.
引用
收藏
页码:1097 / 1103
页数:7
相关论文
共 40 条
[1]   FORMATION OF RING-RETAINING PRODUCTS FROM THE OH RADICAL-INITIATED REACTIONS OF BENZENE AND TOLUENE [J].
ATKINSON, R ;
ASCHMANN, SM ;
AREY, J ;
CARTER, WPL .
INTERNATIONAL JOURNAL OF CHEMICAL KINETICS, 1989, 21 (09) :801-827
[2]  
BATHIA K, 1974, J PHYS CHEM-US, V78, P2335
[3]   THE MECHANISMS OF THE REARRANGEMENTS OF ALLYLIC HYDROPEROXIDES - 5-ALPHA-HYDROPEROXY-3-BETA-HYDROXYCHOLEST-6-ENE AND 7-ALPHA-HYDROPEROXY-3-BETA-HYDROXYCHOLEST-5-ENE [J].
BECKWITH, ALJ ;
DAVIES, AG ;
DAVISON, IGE ;
MACCOLL, A ;
MRUZEK, MH .
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2, 1989, (07) :815-824
[4]  
Berdnikov V.M., 1972, KINET CATAL+, V13, P986
[5]  
BLOODWORTH AJ, 1984, J CHEM SOC PERK T 2, P523, DOI 10.1039/p29840000523
[6]   HYDROCARBON RADICAL REACTIONS WITH O-2 - COMPARISON OF ALLYL, FORMYL, AND VINYL TO ETHYL [J].
BOZZELLI, JW ;
DEAN, AM .
JOURNAL OF PHYSICAL CHEMISTRY, 1993, 97 (17) :4427-4441
[7]   CRITICAL-REVIEW OF RATE CONSTANTS FOR REACTIONS OF HYDRATED ELECTRONS, HYDROGEN-ATOMS AND HYDROXYL RADICALS (.OH/.O-) IN AQUEOUS-SOLUTION [J].
BUXTON, GV ;
GREENSTOCK, CL ;
HELMAN, WP ;
ROSS, AB .
JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA, 1988, 17 (02) :513-886
[8]   AROMATIC HYDROXYLATION .8. A RADIATION CHEMICAL STUDY OF THE OXIDATION OF HYDROXYCYCLOHEXADIENYL RADICALS [J].
BUXTON, GV ;
LANGAN, JR ;
SMITH, JRL .
JOURNAL OF PHYSICAL CHEMISTRY, 1986, 90 (23) :6309-6313
[9]   DIRECTING EFFECTS OF PHENYL SUBSTITUTION IN THE REACTION OF OH RADICAL WITH AROMATICS - THE RADIOLYTIC HYDROXYLATION OF BIPHENYL [J].
CHEN, XF ;
SCHULER, RH .
JOURNAL OF PHYSICAL CHEMISTRY, 1993, 97 (02) :421-425
[10]   RADIATION-CHEMISTRY OF CARBOHYDRATES .3. MASS-SPECTRA OF TMS-ETHERS OF DEUTERATED POLYALCOHOLS - CONTRIBUTION TO STRUCTURAL INVESTIGATION OF SUGARS [J].
DIZDAROGLU, M ;
HENNEBERG, D ;
SONNTAG, CV .
ORGANIC MASS SPECTROMETRY, 1974, 8 (JAN) :335-345