Study On Synthesis Of Isooctanoic Acid By Catalytic Oxidation Of Oxygen To Isooctanol

Isooctanoic acid(also known as 2-ethylhexanoic acid)is an important fine chemical,widely used in coatings,inks,plastics,drugs,pesticides,defence and other fields.Isooctanoic acid is an alternative chemical to naphthenic acid,and most of which is used to produce isooctanoic acid.Usually,isooctanoate's performance is better than naphthenate and its application is more extensive.At present,the raw materials of isooctanoic acid synthesis are isooctylene aldehyde,isooctyl aldehyde,isooctanol.Isooctylene aldehyde and isooctyl aldehyde are organic intermediate products,which have unstable performances.Therefor,there is no mass production in industry.There are two main methods for the synthesis of isooctanoic acid from isooctanol: First,by strong oxidizer,such as potassium permanganate,potassium dichromate and nitric acid,the composition of product is complex and the pollution is very serious;Second,the dehydrogenation of sodium hydroxide to sodium isooctanoate firstly,and then isooctanoic acid was prepared by acidification.The process route is long,dangerous,corrosive and heavily polluted.These methods are not ideal synthetic method for the preparation of isooctanoic acid.The production process of isooctanol is mature,low cost,and production capacity has reached the saturation state.The study synthesis of isooctanoic acid by oxidation of isooctanol is one of the hotpots in chemical field.In this study,isooctanol was used as raw material,oxygen direct oxidation synthetic isooctanoic acid with the use of green catalyst.The preparation of isooctanoic acid by the direct oxidation of oxygen under mild conditions,and by using quaternary ammonium phosphotungstate,silica-supported quaternary ammonium phosphotungstate and iron spinel as catalyst were studied respectively.The experiment study influencing factors and the process of oxidation reaction,and reaction mechanism of direct oxidation of isooctanoic acid by quaternary ammonium phosphotungstate.Study on the preparation of quaternary ammonium phosphotungstate by double decomposition and using it as catalyst,oxygen direct oxidation to synthesize isooctanoic acid,the optimal conditions for preparation of isooctanoic acid: mole ratio of phosphotungstic acid and cetyltrimethylammonium chloride was 1:3,the amount of catalyst 3%,reaction temperature of 85?,reaction time of 18 h and the high yield of isooctanoic acid up to 72%;With silica-supported quaternary ammonium phosphotungstate by sol-gel method,as a kind catalyst,reaction conditions:the supported amount of 30%,reaction time was 24 h and the yield of isooctanoic acid up to 59%.The silica-supported quaternary ammonium phosphotungstate was reused;With iron spinel by sol-gel method,as catalyst,the performance of the catalysts for synthetic isooctanoic acid,was investtigated in a fix bed reactor.The optimal conditions,reaction temperature of 320?,Reaction pressure was 0.4MPa,space was 3h-1 and yield of isooctanoic acid up to 33%.Catalysts was characterized by IR,UV,XRD,BET,SEM.The oxidation products were analyzed by GC and IR.