Autoxidation of Olefins Accompanying a Novel Hydrogen Transfer in a

52 Autoxidation of Olefins Accompanying a Novel Hydrogen Transfer in a Silent Downloaded by UNIV OF CALIFORNIA SANTA BARBARA on May 27, 2018 | https://pubs.acs.org Publication Date: January 1, 1968 | doi: 10.1021/ba-1968-0076.ch052

Discharge NOBORU SONODA, SHINJI YAMAMOTO, KENJI OKUMURA, SHUHEI NODA, and SHIGERU TSUTSUMI Department of Chemical Technology, Faculty of Engineering, Osaka University, Yamadakami, Suita, Osaka, Japan

The vapor-phase oxidation of olefins with oxygen or air has been carried out in a silent discharge. In the oxidation of cyclohexene, saturated products such as cyclohexanol and cyclohexanone were produced in comparable yields with corresponding α,β-unsaturated derivatives. In the absence of oxygen, dimeric products such as bicyclohexyl, 3-cyclohexylcyclohexene, and 3,3'-bicydohexenyl were formed; their relative product concentrations and the oxidation products described above demonstrate that allylic cyclohexenyl radical and cyclohexyl radical may be the main intermediates in these reaction systems. The formation of saturated products suggests that these oxidations may pro ceed accompanying a novel hydrogen transfer which may be occurring through some energetic process caused by the silent discharge.

Although extensive studies have been done on the autoxidation of olefins, only a few reports have been published on these oxidations in a silent discharge. Fujimoto (7) and Sugino and co-workers (19) have reported the oxidation of ethylene and confirmed many of the reaction products. Inoue (13) reported that air oxidation of cyclohexane i n the vapor phase at atmospheric pressure i n a silent discharge led to the formation of cyclohexanol and cyclohexanone. H e concluded that the first step of the reaction may be the formation of atomic oxygen through bond fission of the oxygen molecule by electron impact, followed by hydrogen 352

Mayo; Oxidation of Organic Compounds Advances in Chemistry; American Chemical Society: Washington, DC, 1968.

52.

SONODA E T

Autoxidation in a Silent Discharge

AL.

353

Downloaded by UNIV OF CALIFORNIA SANTA BARBARA on May 27, 2018 | https://pubs.acs.org Publication Date: January 1, 1968 | doi: 10.1021/ba-1968-0076.ch052

abstraction from cyclohexane by the atomic oxygen, and the rest of the reaction process may be similar to that of autoxidation. In this paper, we report some observations on oxidation reactions of cyclohexene and propylene under silent discharge. A mixture of cyclohexene or propylene and air or oxygen under atmospheric pressure was allowed to react i n a silent discharge tube at room temperature. Silent discharge was maintained under 60-cycle alternating current at 16 kvolts.

Experimental Materials. Cyclohexene, obtained by dehydration of reagent grade cyclohexanol (3), was heated at reflux over sodium metal, fractionated on a 60-cm. Helix packed column, stored over sodium, and filtered just before use. N o impurity was found by gas chromatography (column, T C P and Si-550; carrier gas, helium). Propylene (Neriki Research Grade) used showed no impurity by gas chromatography ( column, active carbon and acetonylacetone). Procedure. C Y C L O H E X E N E . A l l reactions were carried out i n a flow apparatus. A i r was stored in a 20-liter gas holder and was introduced under 60 cm. of water head. The flow rate was regulated and measured with a soap bubble flow meter. The metered air was passed through an anhydrous calcium chloride tube and then into a cyclohexene evaporator, dipping i n a constant temperature bath. The composition of the gas mixture was controlled by regulating the bath temperature and was determined from the weight of cyclohexene vaporized and the volume of air passed. The gaseous mixture was transferred to a Siemens-type silent discharge tube: borosilicate glass, discharge length, 24 cm.; space gap, 3.5 mm.; discharge space volume, 50 m l . The secondary voltage applied to the discharge tube was fixed at 16 kvolts, and the secondary current was 1.0 ma.; 60-cycle alternating current was used. The circuit i n cluded a voltmeter and milliammeter. During the reactions, the tempera ture of the discharge tube was 4 0 ° - 5 0 ° C . (Separate experiments con firmed that product distribution was hardly affected by the temperature in a range 2 5 ° - - 5 0 C . ) . The flow rate of the air was fixed at 1 ml./sec. for experimental Runs 1-4. Condensable products and unreacted cyclo hexene were collected i n traps at 0° and at —78°C. Gaseous products were collected i n a gas holder at atmospheric pressure. L i q u i d products were analyzed quantitatively by gas chromatography using a 2-meter column of PEG-6000 and a 2-meter column of Si-500 at 1 6 0 ° C , carrier gas, helium. Gaseous products were also analyzed by gas chromatography; for hydrogen, methane, ethylene, ethane, and carbon dioxide using a 2-meter column of activated charcoal at 1 8 0 ° C , carrier gas, helium and nitrogen, and for all hydrocarbons using a 5-meter column of acetonyl acetone at 0 ° C , carrier gas, helium. o

Runs 1-4. Unreacted cyclohexene was removed from the liquid prod ucts under reduced pressure at room temperature. The presence of small amount of hydroperoxides, confirmed by a positive lead tetraacetate test,



354

O X I D A T I O N O F ORGANIC C O M P O U N D S

II

was found i n the residual liquid, and the amount was determined iodometrically. The modified method of Wibaut titration (21), where the per oxides react with potassium iodide in 8 0 % acetic acid at 35 °C. i n a carbon dioxide atmosphere, was used. T h i n layer chromatograms of 2,4-dinitrophenylhydrazone derivative from the residual liquid showed strong spots of cyclohexanone and cyclohexenone derivatives, and the presence of formaldehyde which might interfere with the Wibaut titration (11) was not detected. The present method and the Hiatt method (11, 12), whose iodometry is not interferred with by some aldehydes, gave identi cal titers on the residual liquid. The amounts of peroxide were 6.5% for Runs 1 and 2, 5.0% for R u n 3, and 3.5% for R u n 4, calculated as 3-cyclohexenyl hydroperoxide i n the residual liquid. Distillation of the residual liquid d i d not give the pure fraction of hydroperoxides owing to their lower contents; however, thermal decomposition by keeping the liquid at 130 °C. caused a slight increase i n the weight of 2,4-dinitrophenylhydrazone of the ketones. These facts indicate that these peroxides may be composed mainly of cyclohexyl hydroperoxide and 3-cyclohexenyl hydroperoxide, however, the ratio of the two peroxides was not deter mined. Gas chromatographic analyses of the residual liquid are shown i n Table II; small amounts of these alcohols and carbonyl compounds may arise from pyrolysis of the hydroperoxides during the gas chromatography. Three fractions were isolated from the residual liquid b y preparative gas chromatography using a 3-meter column of PEG-6000 at 155°C., carrier gas, nitrogen. Fraction 1 was found to have the same retention time as that of authentic cyclohexanone, and the infrared spectrum showed a strong absorption band at 1720 c m . ' ( C = 0 ) . The 2,4-dinitrophenylhydrazone derivative was prepared, and a mixed melting point with an authentic sample was not depressed, m.p., 156°-157°C. [literature value 160.2°C. 1

(5)]· Table I.

Gaseous Reactant, Composition, mole % Run

Cyclohexene

Air

Cyclohexene Oxygen mole ratio

1 2 3 4

11.4 15.8 28.8 59.8

88.6 84.2 71.2 40.2

0.61 0.89 1.91 7.00

Gas Chromatographic

Cyclohexene, Conversion ratio

Cyclohexanol

21.3 18.1 11.3 3.6

13.8 17.3 16.3 14.6


52.

SONODA E T A L .

355


Fraction 2 showed the same retention time as that of authentic cyclohexanol, and its infrared spectrum showed a strong absorption band at 3350 cm." ( — O H ) . The α-naphthylurethane derivative was prepared, and a mixed melting point with an authentic sample was not depressed, m.p., 128°-129°C. [literature value, 128°C. ( 1 7 ) ] .


1

Fraction 3 showed two retention times: (a) the same as that of cyclohexenol, and ( b ) the same as that of cyclohexenone; the infrared spectrum showed strong absorption bands at 3350 c m . ' ( — O H ) and 1680 cm." ( C = 0 conjugated). This was separated into two fractions by Girard's Ρ reagent. The a-naphthylurethane derivative of cyclohexenol was not depressed, m.p., 154.5 °-155.5°C. [literature value, 156°C. ( 2 2 ) ] . 1

1

The 2,4-dinitrophenylhydrazone derivative of Fraction 3b, ketonic part, was prepared, and a mixed melting point with an authentic deriva tive of cyclohexenone was not depressed, m.p., 167°-168°C. [literature, 163°C. ( I ) ] . To isolate acidic products which were not found b y gas chromato graphic analysis, the crude products were treated by ordinary methods, but only small amounts of viscous brownish red liquid products were obtained, and no adipic acid was isolated. Isolation of cyclohexene oxide was unsuccessful, however; gas chromatographic analysis based on the two columns showed clearly the presence of cyclohexene oxide. Gaseous products included ethylene, 1,3-butadiene, carbon dioxide, and an u n identified C hydrocarbon i n the ratio of 12:6:3:1. Trace amounts of other gaseous hydrocarbons were also detected, and any gaseous peroxy compound was not detected. These hydrocarbons were considered to be decomposition products of activated cyclohexene. 4

Run 5. Commercial nitrogen used was purified by passing it through an alkaline solution of pyrogallol and a series of concentrated sulfuric acid, silica gel, and anhydrous calcium chloride tubes. The flow rate of nitrogen was fixed at 40 ml./min. Unreacted cyclohexene and low boiling products were removed from the collected products at reduced pressure. Analysis of Oxidation Products Cyclohexanol + Cyclohexanone

Components, wt. % Cyclohexene Cyclo Cyclo Cyclo oxide hexanone hexenol hexenone 16.0 15.6 12.8 11.9

28.4 29.3 33.1 32.5

21.1 18.2 20.7 24.7

12.0 11.0 9.7 6.8

Cyclohexenone mole ratio

Ketones Alcohols' mole ratio

0.59 0.68 0.53 0.45

0.88 0.74 0.69 0.80


356

OXIDATION O F

Table II.

ORGANIC COMPOUNDS

Π

Products from Discharge Reaction of Cyclohexene in the Absence of Oxygen (Run 5) a

Compound

mmole/hr.

Bicyclohexyl 3-Cyclohexylcyclohexene 3,3'-Bicyclohexenyl Unidentified C Cyclohexane 1,3-Cyclohexadiene Unidentified and residue ( C unit)

0.43 0.95 0.56 0.12 0.30 found 0.98


1 2

mmole /hr.

Compound

0.45 trace 1.6 trace 0.36 0.1 0.51 trace trace 0.19 trace

Hydrogen Methane Ethylene Ethane Acetylene Propylene Propane n-Butane 1-Butene Butadiene Other C -products

6

6

4

"Composition of gaseous reactant: cyclohexene, 27.2%; nitrogen, 72.8%. Feed rate of cyclohexene, 40.2 mmoles/hr. Quantitative analysis was not done. 6

Gas-chromatographic analysis (column: PEG-6000, 2 meters, column temperature 180°C., carrier gas, H e ) of the residue showed that it con sisted of three main products. The first peak was identified as bicyclo hexyl, the second as 3-cyclohexylcyclohexene, and the third as 3,3'-bicyclohexenyl. The residue was distilled, and a fraction boiling at 9 0 ° 122°C./20 mm. H g was collected. This fraction was poured into 10 times its volume of acetic acid. The solution was cooled to 0 ° C , and bromine was added. Colorless needle crystals and a red viscous oily liquid were obtained. The crystalline material was recrystallized from acetic acid and melted at 157.5°-160°C. (decomp.) [literature, 158°C. ( 6 ) ] . A mixed melting point with an authetic tetrabromide of 3,3'bicyclohexenyl was not depressed. The oily liquid was purified by column chromatography (silica gel, 80 mesh; eluant, petroleum ether) and distilled. A colorless oily liquid (b.p., 123°-125°C./0.5 mm. H g , n 1.5530) was obtained. The infrared spectrum was that of 3-cyclohexylcyclohexene. Analysis: calculated for C H o B r : C , 44.47; H , 6.22. F o u n d : C , 44.48; H , 5.99. The gas chromatogram of the remaining acetic acid solution showed that the two peaks identical with those of 3-cyclohexylcyclohexene and D

1 2

2 0

2

2

Table III. Gaseous Reactant, Composition, mole % Propylene 99 95 80 70

Oxidation Products of Oxidation Products,

Oxygen

Methyl Alcohol

Acetaldehyde

Propylene Oxide

1 5 20 30

0.20 0.60 1.47 1.68

trace 0.35 1.24 1.62

trace trace trace trace


52.

SONODA E T A L .

357


3,3'-bicyclohexenyl disappeared, and the peak identical with that of bicyclohexyl remained. The gas chromatogram of the fraction having b.p., 90°-122°C./20 mm. H g showed that at least 13 peaks wçre present before the bicyclohexyl peak. These amounts were small, and since no further investigation was done, they were treated as unidentified prod ucts. A small peak was found close behind the peak of 3,3'-bicyclohexenyl. This seemed to be a C product. The gas chromatogram of the low boiling fraction showed one peak identified as cyclohexane on two columns: T C P 2 meters, 8 0 ° C ; D N P 2 meters 7 0 ° C , carrier gas, H e . The ultraviolet spectrum of this fraction showed A 256 m/χ, indicating the presence of 1,3-cyclohexadiene (9). This was also confirmed b y treating (11) the fraction with maleic anhydride giving the Diels-Alder adduct, bicyclo-2,2,2-oct-5-ene-2,3-dicarboxylic anhydride; m.p., 1 4 5 ° 146.6°C, mixed melting point with an authentic sample (8) showed no depression.


i2

m

a

x

Autoxidation without Discharge. To compare our results with nor mal autoxidation, the reaction was carried out using a reaction mixture similar to R u n 4 without silent discharge. L o w conversion of cyclohexene (0.051% ) was observed at 6 0 ° C , indicating that the discharge oxidation was hardly affected by the normal autoxidation process under the present reaction conditions. The major product was 3-cyclohexenylhydroperoxide, and minor products were 3-cyclohexenol, 3-cyclohexenone, cyclohexene oxide, and trace amounts of residue; saturated materials such as cyclohexanol and cyclohexanone were not detected. The conversion of cyclo hexene was raised to 0.15% when the reaction temperature was elevated to 1 4 0 ° C ; however, the kinds of product were not changed. P R O P Y L E N E . Propylene and oxygen were premixed i n a fixed ratio, and the mixed gas was introduced to the discharge tube at the rate of 80 ml./min. The reaction was carried out at 0 ° C . i n the same way as that of cyclohexene. A l l products were analyzed by gas chromatography using PEG-6000, T C P , and Si-DC550 columns for the oxygen-containing products listed i n Table III, Golay U (90 meters), acetonyl-acetone and active carbon columns for the liquid and gaseous hydrocarbon products. Propylene under Silent Discharge mmoles/200 mmoles Propylene n-Propyl PropionAcrolein Alcohol aldehyde 0.15 0.35 1.04 1.48

0.044 0.11 0.25 0.27

0.25 0.78 1.68 1.95

Allyl Alcohol

Acetone

Isopropyl Alcohol

0.14 0.34 0.82 0.95

0.32 1.14 2.53 3.29

0.60 1.63 3.46 3.39


358

OXIDATION O F

ORGANIC COMPOUNDS

Π

In the absence of oxygen, about 82 peaks of hydrocarbon products were observed in the gas chromatogram, which showed that the main products consisted of C hydrocarbons (Table I V ) , hydrogen, methane, acetylene, ethylene, ethane, methylacetylene, aliène, propane, 1-butene, and butadiene. 6


Table IV,

Relative Amounts of Q Products from Propylene in the Absence of Oxygen Relative Amount, %

Products

28.0 5.6 40.1 10.0 12.6 3.7

2,3-Dimethylbutane 2-Methylpentane 4-Methyl-l-pentene 1-Hexene 1,5-Hexadiene Unidentified C 6

Results and

Discussion

A n experiment in the absence of oxygen is summarized i n Table II ( R u n 5). Bicyclohexyl, 3-cyclohexylcyclohexene, and 3,3'-bicyclohexenyl were the main products; small amounts of 1,3-cyclohexadiene and cyclohexane was also formed. The dimeric products may be formed by cou pling reactions between cyclohexyl radicals and allylic cyclohexenyl radicals, in which ratio of rate constant φ ^ = ^ ment with statistical expectation (φ =

2)

^ ^

(16).

1/2

^ is 1.9 i n agree

Cyclohexane, cyclo

hexene, and 1,3-cyclohexadiene might be formed by hydrogen transfer reactions between these radicals.

(1)

ο

·

+

·

ο

—oo

Although ion-molecule processes would be possible in some electron impact reactions, this process would not lead to the formation of dimeric products formed in the present experiments (20). Ethylene was the major gaseous product. Ethylene and butadiene may be produced from the reverse Diels-Alder reaction of cyclohexene (10) since they were also


52.

SONODA E T A L .

359


produced in the presence of oxygen, and acetylene was probably formed by butadiene cleavage. It is not clear how hydrogen and propane are formed i n this system. C H 2


ο

C H 4

»

6

4

C H4 2

+

C H

6

(4)

+

C H

2

(5)

4

2

The results of the oxidation of cyclohexene are summarized i n Table I. Cyclohexanol and cyclohexanone were obtained even at high oxygen concentration ( Table I, Run 1 ) in yields comparable with that of 3-cyclohexenol, 3-cyclohexenone, and cyclohexene oxide. This indicates that the addition of a hydrogen atom to cyclohexene occurred fairly effectively in this reaction system despite the presence of oxygen molecules. Analysis of crude products showed the presence of small amounts of hydroperox ides, and they were decomposed during the gas chromatography; how ever, this decomposition d i d not cause the hydrogen addition. Jarvie and Cvetanovic (14) have reported the reaction of 1-butene with activated oxygen i n microwave discharge, where 1-butene is not activated by the discharge; hence, the hydrogen addition reaction similar to the present case is not observed, and the kinds and distribution of the products are different from those of our experiments. In the present oxidation, cyclohexyl radicals and cyclohexenyl radi cals may react with oxygen molecules to form the corresponding peroxy radicals since oxygen molecules are effective scavengers of hydrocarbon free radicals. This was suggested by the fact that no coupling products were obtained i n the presence of oxygen. Cyclohexyl peroxy radicals and cyclohexenyl peroxy radicals may be the most probable intermediates of the reaction in the presence of oxygen. R'

+

0

-

2

--Ô

-

ROO-

(6)

ό

Then, a major part of these radicals would be consumed by chain termination to form corresponding alcohols and ketones. Yokohata and Tsuda (23, 24, 25) have suggested that the silent discharge reaction can well be interpreted in terms of radiolysis caused by the ionizing radiation of high L E T (Linear Energy Transfer), and this would help explain the short chains of this oxidation.


OXIDATION OF ORGANIC COMPOUNDS II

360


^CHOO ·

+

^CH—OO ·

^CH—OH

+

^C=O

+

0

(7)

2

However, the ratios of the unsaturated materials to the saturated mate rials and of the ketones to the alcohols ( Table I ) indicate that the yields of unsaturated materials are higher than those of saturated products, especially cyclohexenol. [The excess alcohol might come from 2 R O O · - » 2 R O + O2; however, its importance i n the gas phase is unknown.] It was suggested from the above that some cyclohexenol and possibly cyclohexenone may be formed from cyclohexenyl hydroperoxide which is pro duced from chain reactions initiated by the cyclohexyl peroxy radical and cyclohexenyl peroxy radical as shown below.

Q - < X > .

+

Q

Q - O O .

+

Q

+

—

o

0-°°

•

2

h

»

Q - O O H

-

Q

-

0

0

-

+

Q

(8)

+

(9)

*

do)

Decomposition of the hydroperoxides would be considered i n terms of the following general scheme; for example, for cyclohexyl hydroperoxide:

C^-pon

O~ * o

~(^\-Q.

+

+

(ii)

.OH

Ο — * 0~

oh

Ό

+

+

R—H

(12)

(13)

The formation of water, detected by the copper sulfate test, may be consistent with the above scheme. The decreasing yield of cyclohexene oxide with decreasing oxygen concentration suggests that cyclohexene oxide could be formed from the direct reaction of cyclohexene with


SONODA E T A L .


52.

361


atomic oxygen (14, 20) produced by electron impact on molecular oxy gen. Although cyclohexene oxide could be formed by the interaction of cyclohexene and intermediate peroxy radicals (2), this process would be inefficient i n producing cyclohexene oxide ( I S ) . The first step of the reaction may be the formation of cyclohexyl radicals and cyclohexenyl radicals from cyclohexene by silent discharge. These free radicals might be formed by a cyclohexenyl radical and a hydrogen atom's being generated by electron impact, and the hydrogen atom may add to cyclohexene to give a cyclohexyl radical. However, if hydrogen atoms are formed i n the presence of oxygen molecules (Runs 1-4), they may also react with oxygen, and be con sumed largely by the formation of hydrogen peroxy radicals. Then the formation of cyclohexyl radicals should be restricted, and the yield of saturated products, cyclohexanol, and cyclohexanone, should decrease. However, as shown i n Table I, the composition of products obtained i n our experiments was nearly independent of the ratio of oxygen and cyclohexene, therefore, addition of a hydrogen atom to cyclohexene may not be a main path. Thus, the following two molecular processes may occur.

ο

Q-

O"

(16)

Ο — Ο

+

ο (

• «

Ο 2e

+

c-C H 6

10

+

Ο

|c-C H j 0

n

+

4- e

Ο

(17)

Ο

In Equation 16, the first step is the activation of a cyclohexene molecule by electron impact, and the second step is the reaction of the activated cyclohexene molecule with a normal cyclohexene molecule resulting i n intermolecular allylic hydrogen transfer. In Equation 17 the first step is ionization of a cyclohexene molecule by electron impact, and


362

OXIDATION

O F ORGANIC COMPOUNDS

II

the second step is an ion-molecule reaction followed b y neutralization. Oxidation products of propylene are shown in Table III. To discover the precursor of these products, C components of the products, formed i n the absence of oxygen, were analyzed (relative amounts are shown i n Table I V ) .


6

These results suggest that isopropyl, η-propyl, and allyl radicals may be formed as the main intermediates i n these reaction systems; however, further precise information was difficult to obtain because of the complex product distribution and instability of a mixture of the oxidation products owing to the presence of small amounts of acids and peroxidic components not analyzed. The formation of the η-propyl radical from propylene suggests that this hydrogen transfer should proceed through some energetic process caused by silent discharge because a normal hydrogen atom addition to propylene proceeds almost exclusively to the terminal carbon (15). Thus, two molecular processes similar to those in the reactions of cyclohexene may be plausible to interpret the hydrogen transfer. Literature Cited (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) (24) (25)

Bartlett, P. D., Woods, G. F.,J.Am. Chem. Soc. 62, 2933 (1940). Brill, W. F.,J.Am. Chem. Soc. 85, 141 (1963). Coleman, G. H., Johnston, H. F., Org. Syntheses, Coll. 1, 183 (1941). Cvetanović, R. J., J. Chem. Phys. 25, 376 (1956). Farkas, Α., Passaglia, E., J. Am. Chem. Soc. 72, 3333 (1950). Farmer, Ε. H., Michael, S. E., J. Chem. Soc. 1942, 513. Fujimoto, H., Bull. Chem. Soc. Japan 13, 281 (1938). Hammond, G. S., Warkentin, J., J. Am. Chem. Soc. 83, 2554 (1961). Henri, V., Pickett, L. W., J. Chem. Phys. 7, 439 (1939). Hershberg, Ε. B., Runoff, J.R.,Org. Syntheses, Coll. II, 102 (1943). Hiatt, R., Gould, C. W., Mayo, F.R.,J. Org. Chem. 29, 3461 (1964). Hiatt,R.,Strachan, W. M. J., J. Org. Chem. 28, 1894 (1963). Inoue, E., Bull. Tokyo Inst. Technol., Ser. A, 1957 (2) 1. Jarvie, J. M. S., Cvetanovic, R. J., Can. J. Chem. 37, 529 (1959). Moore, W. L., J. Chem. Phys. 16, 916 (1948). Pryor, W. Α., "Free Radicals," p. 15, McGraw-Hill, New York, 1966. Shriner, R. L., Fuson, R. C., Curtin, D. Y., "The Systematic Identifica tion of Organic Compounds," 4th ed., p. 280, Wiley, New York, 1956. Sickle, D. E. Van, Mayo, F. R., Arluck, R. M., J. Am. Chem. Soc. 87, 4824 (1965). Sugino, K., et al., J. Chem. Soc. Japan, Pure Chem. Sec. 86, 1200 (1965). Wakeford, B. R., Freeman, G.R.,J.Phys. Chem. 68, 2635 (1964). Wibaut, J. P., van Leeuwen, H. B., Van der Wal, B., Bee. trav. chim. 73, 1033 (1954). Willstater,R.,Sonnenfeld, E., Ber. 46, 2952 (1913). Yokohata, Α., Tsuda, S., Bull. Chem. Soc. Japan 39, 53 (1966). Ibid.,p.1636. Ibid., 40, 294 (1967).

RECEIVED September 29, 1967.


Autoxidation of Olefins Accompanying a Novel Hydrogen Transfer in a

Recommend Documents