Preparation And Characterization Of Cellulose Base Solid Acid Catalyst

In recent years,as the environmental awareness of people have improved and the environmental protection from government have strengthen,the shortcomings like serious pollution,hard treatment belonging to liquid acid catalyst were also aggregated greatly.Therefore,seeking an alternative acidic catalyst or a kind of acidic catalyst which can be replaced partly has become a hot topic.Researchers has paid high attention to some catalyst materials with low prices and good catalytic property such as solid super acid,zeolite and heteropoly acid.In this paper,two different types of carbon-based solid acid have been investigated,and their catalytic propertie has been evaluated.Firstly,cellulose was used as raw material,and regarded cellulose and1-buty-3-methyl imidazole chloride salt?[Bmim]Cl?as cellulose hydrogel.And then dry cellulose aerogel by the means of freeze drying and supercritical drying.At last,samples were analyzed through TGA,SEM,BET.Results show that cellulose aerogel?CA?adopted supercritical drying method has better pore structure.The aerogel with 3%cellulose concentration has the highest specific surface area containing 290m²/g.What is more,the stability of aerogel with 2%?3%?4%cellulose concentration is higher than the original cellulose,while the aerogel with 1%cellulose concentration is lower than the original cellulose.Using CA as carbon-based material and then regarding sulfur trioxide pyridine complex as sulfonating agent were the next step to make sulfonated carbon aerogel?SCA?.Meanwhile,sulfonated carbon powder?CCSA?was prepared by cellulose with incomplete carbonation and concentrated sulphuric acid regarded as sulfonated reagent.And the two kinds of solid acid were characterized by the means of FTIR,TGA,SEM and acid value analysis.Results showed that increasing CA surface area and cellulose-SO₃ can enrich SCA acidity significantly,the maximum would be4.96mmol/g.The carbonization temperature of CCSA acid value between 400-600?is inversely proportional to carbonization temperature,and it's acidity dropped from1.87mmol/g to 1.02mmol/g.While when the carbonization temperature reaches650?,CCSA acidity will rise to 1.46mmol/g.It can preliminary infer that the result is associated with the number of carboxylic and sulfonic group change from infrared spectrogram.Finally,the last step is to synthesize biodiesel under the catalysis of SCA?CCSA and Amberlyst-15 resin,and then evaluate the catalytic activity of the three solid acids in biodiesel synthesis.Under the condition of 90?reaction temperature and 4 h reaction time,the conversion rate of fatty acid methyl ester which use SCA?CCSA?Amberlyst-15 as catalyst can reach 58.5%,40.5%and 25.8%.So it's can be concluded that the catalytic activity relationship of the three catalysts is SCA>CCSA>Amberlyst-15.From the above results,it can be summarized that SCA is a kind of solid acid with high specific surface area,acidity and the catalytic activity.