Study On Oxidation Characteristics And Products Of Anisole And Phenetole

In order to investigate the oxidation activity and stability of anisole and phenetole,the research on the oxidation characteristics and oxidation products of them was carried out.The main research contents and results were:(1)A mini closed pressure vessel test(MCPVT)device was designed to study the temperature and pressure behavior of the oxidation proccess of anisole and phenetole.(2)MCPVT was used to trace and detect the oxidation process of anisole and phenetole.The oxidation characteristics of anisole under high pressure conditions were:a significant exothermic phenomenon occurred,when the temperature rised to 195.9 ℃.The oxidation characteristics of phenetole under high pressure conditions were:a significant exothermic phenomenon occurred,when the temperature rised to 195.0 ℃,and there was an obvious decreasing of pressure in the mean time.The additives were added in the oxidation system,they had a significant effect on the oxidation reaction of anisole and phenetole.The addition of tert-butyl hydroperxide(TBHP)or hydrogen peroxide led to the decreasing of exothermic oxidation temperature,the increasing of reaction rate and oxygen absorption.They could promote oxidation.The addition of iron powder or iron oxide powder led to the decreasing of exothermic oxidation temperature,increasing of reaction rate and oxygen absorption,they could promote oxidation.The addition of water or ascorbic acid caused the increasing of exothermic oxidation temperature or vanishing of exothermic phenomenon and the decreasing of oxygen absorption.They could inhibiting oxidation.(3)The peroxides from the oxidation of anisole and phenetole at atmospheric pressure or high pressure conditions were titrated by the iodine volume method,and oxidation intermediates and reaction properties were discussed.The experimental results at atmospheric pressure indicated that the peroxides of anisole were produced in the range of 140-150 ℃,and the longer the reaction time,the lower the peroxide value.For phenetole,the peroxides were produced in the range of 100-170 ℃,and the peroxide value increased first and then decreased with increasing reaction temperature,and reached the maximum at 160 ℃;the peroxide value increased first and then decreased with increasing reaction time,and reached the maximum at 3 h.The experiment results at high pressure showed that peroxides of anisole were produced in the range of 160～170 ℃,and the longer the reaction time,the lower the peroxide value.The initial oxygen pressure had little effect on the peroxide value.For phenetole,the peroxides were produced in the range of 110～180 ℃,the peroxide value increased first and then decreased with increasing reaction temperature,and reached the maximum at 160 ℃;the peroxide value increased first and then tended to be stable with increasing initial oxygen pressure,and reached the maximum at 1.0 MPa.The reaction of anisole with benzyl ether in nitrogen,air or oxygen was carried out.The result showed that oxygen was an essential factor in causing oxidation reaction and the production of peroxides.Moreover,the peroxides from the oxidation of anisole and phenetole were analyzed by thin-layer chromatography,the results showed they both had only one kind of peroxide.(4)The oxidation products of anisole and phenetole under different temperatures was analyzed by gas chromatography mass spectrometry(GC-MS).The result indicated that the oxidation products of anisole were formic acid phenyl ester and o-methoxy phenol when the reaction temperature was lower than 200 ℃.However,the oxidation products were complex,including trioxymethylene,methanol,formic acid,phenol and formic acid phenyl ester,when the reaction temperature was higher than 210 ℃.The oxidation products of phenetole were acetaldehyde,phenol,acetic acid phenyl ester and o-ethoxy phenol,when the reaction temperature was lower than 150 ℃.There were 20 kinds of oxidation products,when the reaction temperature was higher than 160 ℃.Main of them were acetaldehyde,acetic acid,phenol,acetic acid phenyl ester,o-ethoxy phenol.