Synthesis of 1,4-Butynediol from HCHO and C2H2 Over CuO-Bi2O3/MgO-SiO2
|Keywords||SiO2-MgO copper bismuth catalyst alkyne aldehyde acetylene copper 1，4-butynediol|
as a kind of organic ingredient 1,4-butanediol rapidly developed in China in recent years, the downstream products contain tetrahydrofuran (THF), y-butyrolactone (GBL), polyethylene terephthalate (PBT), Polyurethane (PU), poly tetramethylene ether glycol (PTMEG), biodegradable plastics poly butylene succinate (PBS) and so on. The Reppe method was used frequently and mature among a number of way to synthesis 1,4-butanediol, It was also the most significant economic benefits of a technology to synthesis 1,4-butanediol. Moreover, There were abundant coal resources in China, especially as the airtight calcium carbide furnace and methanol synthesis of megaton developed rapidly. the method of Reppe was a suitable way to develop in China.The synthesis of 1,4-butynediol with acetylene and formaldehyde was the head of Reppe. Generally copper acetylide with a little bismuth was used as catalyst, However, compared with imported catalyst, the research of alkyne hydroformylation catalyst in China was rather late, research level was fall behind. So carry out the research on the localization of alkyne aldehydes catalyst has significant. In this paper, the SiO2-MgO supports was prepared by sol-gel with supercritical drying method, copper and bismuth was supported on SiO2-MgO, and then the catalyst was applied to reaction of synthesis of 1,4-butynediol. The effect of Mg content, calcination temperature of carriers and catalysts, copper and bismuth content on catalysts were investigated; technological conditions of selected catalyst were carried out; the structure and texture of catalyst were characterized by the means of XRD, TPR, FT-IR, TG-DSC. Based on the above theoretical research, activity evaluation results of catalysts were refered, so some theoretical guidance for the development of high activity, high selectivity of alkyne hydroformylation catalyst was supplied. The main results were as follows:The catalysts which used SiO2 and SiO2-MgO as carriers were prepared. the evaluation of the catalyst showed that the activity of catalyst improved significantly when Mg was introduced to supports. The effect of preparation conditions such as calcination temperature of supports and catalysts, content of Cu and Bi were investigated. The optimum conditions for preparing the catalyst was selected:the content of Mg was 18%, the calcination temperature of carrier and catalyst were 500℃, the content of Cu was 35% and Bi was 2%.The carrier and the catalysts with different content of Mg were characterized. Some results were found that the catalyst which contained 18% Mg and calcinated 500℃showed optimum performance, one of the main reason was that CuO had high dispersion. The adjunction of Mg and the appropriate calcination temperature produced a appropriate interaction between CuO and support. It also made Cu2+ prioritily reduced to Cu+ and zero-valent Cu was inhibited. Cu+ was the active center to generate copper acetylide. The catalyst showed high activity when a large number of Cu+ was existed.Further investigation about technological conditions were carried out. The result showed that the best reaction conditions as follows:the amount of catalysts were 5g as there had 100mL the concentration of 37% formaldehyde, the flow rate is 75-85mL/min and reaction was 20h. Under this condition the conversion rate of formaldehyde reached 92% and the yield of 1,4-butynediol reached 79.4%. The catalyst kept high activity after applying 5 times.