The Industrial Design Of Synthesizing Vanillin From 2-bromo-4-methylphenol

As one of the world's largest producing and consumption spices,vanillin has a huge market.The yield of synthetic spices has been improved continuously.With the application of glyoxylic acid method,the domestic production technology of vanillin in producing process has reached an advanced international level.Moreover,it also got a breakthrough in biotechnology,with the industrial application of synthesis from ferulic acid by means of biosynthesis.However,the p-cresol synthesis route,which gets more researches,has not been implemented.This paper mainly studied the synthesis of vanillin from bromocresol.We finally found a highly efficient synthetic route to obtain vanillin from related references,repeated experiments and detailed analysis.We have set up a small-scale experimental device and got a green and efficient synthetic process route.Compared with guaiacol synthesis route for vanillin and other conventional routes,the bromocresol synthesis route was much more competitive due to the lower cost and less pollution.Two steps synthesis reaction was used for preparation of vanillin.The first step is methoxylation reaction.The raw materials is bromocresol,sodium hydroxide,catalyst,methanol and sodium methoxide.The bromocresol reacts with sodium hydroxide to form bromocresol sodium salt.Then,bromocresol sodium salt reacts with sodium methoxide in the presence of organic solvents and catalyst of cuprous chloride for 3.67 hours at temperature of 50-65?.The yield of methoxylation reaction reached 95%,and the methanol can be recovered by atmospheric distillation.The mother liquor was acidulated by sulphuric acid,extracted by methylbenzene.Methylbenzene can be recovered.The heavy fraction was got,and subjected to rectifying to obtained 4-methyl guaiacol,which is an intermediate to producing vanillin.Through the optimization of the process,the reaction process does not use DMF as solvent in the traditional technology,the consumption of sodium methoxide was greatly reduced.Theprocesshastheadvantageoflowercostandeasieroperation.The second step is air catalytic oxidation reaction:Vanillin was obtained by air catalytic oxidation of intermediate 4-methyl guaiacol,air,sodium hydroxide,catalyst and solvents.The catalyst components are cobalt acetyl acetone(cat 2A)and cobalt chloride(cat 2B).The solvent is polyethylene glycol monomethyl ether(solvent A)and ethylene glycol(solvent B).The optimum process was got by studying the catalyst for oxidation reaction,the raw material ratio of solvents and the kinetic data of oxidation reaction.The yield of oxidation reaction reached 92%,and the total vanillin yield reached 87.4%.The reaction in this study is a green chemical process with good atomic economy.The large-scale industrial production has considerable advantages from the environmental point of view.This paper also gives the mass production material balance of vanillin with producing 1000 tons per year,and the demand for raw and auxiliary materials.It also calculates the energy consumption of the design target,and makes a feasibility comparison with the existing device.This paper also designs the specifications of the main equipments,gives the selection of equipments.At the same time,the three wastes produced were also given.According to the matching analysis of market demand and existing public utility,it is necessary to design a vanillin production plant with a capacity of 1,000 tons/year.Through analysis and calculation,the project need to design 3 sets of high-pressure oxidation reactors,2 sets of methoxylation reactors,2 sets of distillation tower,and 2 sets of wiped-film evaporators.The rectification of solvent A and solvent B uses the same distillation tower by switching,which can meet the distillation needs of the two solvents at the same time.According to energy usage statistics,the total low-pressure steam consumption is 18158.8kg/d,equivalent to 18.2t/d.The total circulating water consumption is 2178.lt/d.