The Research Of Synthesis Of Nitriles By The Dehydrogenation-amination Of Fatty Alcohols Over Cu/SiO₂

Nitriles belong to an important class of compounds in petrochemical that are widely used to produce pharmaceuticals,agricultural chemicals,dyes and ingredient or intermediate for the synthesis of perfume.It also could be used as analytical reagent in high-performance liquid chromatography.Typically,nitriles are synthesized by non-green procedures using hazardous inorganic and organic cyanides such as aldehydes?amination?,alkenes?oxida-tion?,and thioamides?oxidative dehydrosulfurization?.It is unlikely to meet with the demand of today's industry.Therefore,new ways of making chemicals for nitriles need developing.First of all,the mesoporous Cu/SiO₂ catalyst is synthesized by hydrolysis precipitation method used Cu₂Si₂O₅?OH?₂ as the precursor.Cu₂Si₂O₅?OH?₂ was reducted by hydrogen at a certain temperature and the sample of reduction is the Cu/SiO₂ catalyst with catalytic performance.There are two kinds of copper species over the catalyst,one is Cu⁰ and another is Cu₂O.High specific surface area provid a high dispersion of copper species and narrow mesoporous pore could effectively reduced the occurence of side reactions.The fuction of each component of the Cu/SiO₂ catalyst is studied.In this paper,we do the research of one step synthesis of nitriles by the dehydrogenation-amination of C₂-C₈ fatty primary alcohols,lauryl alcohol and citronellol over Cu/SiO₂ catalyst in fixed bed reactor and also put forward a possible reaction mechanism.The products are determind by IR and gas chromatography-mass spectrometry.We study the effect of the reaction conditions?such as reaction temperature,NH₃/alcohol molar ratio and alcohol WHSV?on the reaction.In order to research the plausible effect of the length of carbon chain and unsaturated functional group?double bond?to the reaction.Based on the experiment,the optimal reaction temperature of the linear chain fatty primary alcohols raised with the growth of carbon chain.A big NH₃/alcohol molar ratio and alcohol WHSV are good to the reaction.However,reactant with unsaturated functional group may have hydrogenation as a result of hydrogen which produced in the reaction process.So they need to find the suitable reaction conditions for a high nitrile yield.