Preparation For The Natural Shape Of Carbon-based Catalysts

In the transesterification process of biodiesel, we usually use the liquid acid catalyst, but it is easy to emulsify, lots of industrial waste water and waste, more environmental pollution, complex process and other problems. The carbon-based catalyst is a new solid acid catalyst, Showed higher catalytic efficiency and stability, but use the sugar and starch as the raw material is easily broken, difficult to shape. If we use the natural shape of biomass as raw materials, make a catalyst for the industrial applications in the synthesis of biodiesel. We can complete from the biological material obtained to make biodiesel, it has important theoretical value and prospects of industrial applications。This article focus on the method that by using southern dates’cores as the raw material, after carbonization sulfonation, concentrated sulfuric acid immersion as well as activated charcoal sulfonation to prepare carbon-based solid acid catalyst. For the evaluation by means of transesterification, discussing the influence on catalytic properties from the preparation parameters the study suggests an better method and preparation techniques。By Soaked in concentrated sulfuric acid, the ideal sulphonation temperature is100℃and10hours duration, the acidity is 3.4mmol/g, the strength is150.2N. By charcoal sulfonation, the ideal sulphonation temperature is120℃and3hours duration, the acidity is0.39mmol/g, the strength is148.2N. By activated charcoal sulfonation, the ideal sulphonation temperature is100℃and2hours duration, the acidity is0.58mmol/g, the strength is150.2N.Hydrothermal reaction, anti-crushing force test, TGA, XRD and SEM were conducted on the biomass carbon based solid acid catalysts prepared by three methods respectively. SEM and XRD suggested that the catalyst is consisted of irregular-shaped carbon particles. TG analysis suggested that the biomass carbon based solid acid catalyst prepared by activated charcoal sulfonation displays fine thermal stability in an environment under220℃. Infrared spectroscopy (TG-IR) results show that the preparation of the three preparation methods of carbon-based solid acid catalyst after sulfonated, fused ring introduce the molecular structure of sulfonic acid groups. Hydrothermal reaction indicated that the catalysts’ hydrothermal stability prepared by activated charcoal sulfonation is higher than those prepared by carbonization sulfonation or concentrated sulfuric acid immersion.Using soybean oil as the material and biomass carbon based solid acid catalyst prepared by activated charcoal sulfonation, to prepare biodiesel by transesterification. Optimize the experiment parameters by orthogonal experimental design and the optimum operating parameters are:molar ratio of methanol to oil:10:1, reaction time:8hours; reaction temperature:70℃, catalyst quality:2.3g. The result showed the biodiesel conversion rate is96.5%.Finally, investigated the carbon based solid acid catalyst by activated charcoal sulfonated reusability, by recycling the catalyst that the use of untreated, after reused five time, the yield of biodiesel can be attained75%.Biomass carbon based solid acid catalyst has many advantages such as high catalytic efficiency, good stability, easy recycling, environmental friendly and economic.