Catalytic Performance Of Carbon-Based Solid Acidcatalyst For Biodiesel

The current industrial production of biodiesel was generally used NaOH, H2SO4 et al homogeneous acid-base catalyst ,the catalyst was cheap and had high catalytic activity, but the catalyst post-processing technique was complex and liquid waste was easy to abuse environment pollution, acid catalyst would cause serious corrosion on the device. The heterogeneous catalyst was more dominant than the homogeneous catalyst, easily separated from the product and would not cause acidic waste water pollution, environmental pollution. Today,under the green revolution ,the solid catalyst was more attention. Solid alkali as the catalyst, the formation of large amount of unsaponifiable matter emulsification was difficult to separate the product, resulting in rising costs. Therefore, solid acid catalyst was a better choice for biodiesel.The activated carbon was raw material in the experiment, We used the method which were sulfonation and the diazonium salt reduction method to prepare carbon-based solid acid catalyst. We examined the activity of solid acid catalyst by a short chain acetic acid and long chain oleic acid esterification with ethanol. The results showed that carbon based solid acid catalyst by sulfonation had low activity. Therefore the carbon-based solid acid prepared was putted emphasized on diazonium salt reduction . We study the arbon-based solid acid catalytic which were prepared with different activated carbon materials by diazonium salt reduction.The study results showed that coal based activated carbon was prepared solid acid catalysts which had the highest activity, while the coconut shell, fruit shell activated carbon were prepared carbon based solid acid which had the worst catalytic activity.We studied the carbon based solid acid catalytic activity with coal activated carbon as raw material by oleic acid with ethanol esterification . The optimum condition reaction was obtained by optimizing the parameters of activated carbon and the diazonium salt of the ratio, hypophosphorous acid reaction time, hypophosphorous acid consumption and other optimal conditions.XRD, EA, BET, SEM, TGA, IR were taken to characterize coal-based activated carbon and activated carbon. The characterization results showed that carbon based solid acid is amorphous carbon structure, catalyst presence sulfonic , sulfonic groups content was 0.64 mmol g-1,and all sulfur of solid catalyst was from the sulfonic groups.The optimum condition reaction was obtained by optimizing the parameters of esterification reaction ,namely: methanol to oleic acid molar ratio of 10:1, carbon-based solid acid catalyst dosage of 7% oleic acid weight, esterification temperature of 80℃and the esterification time of 8h. Carbon-based solid acid catalyst which we had prepared had high catalytic efficiency, environmentally friendly, renewably and other low-costly advantages, but had less stably, not easily recycled recycling and needed to re-activate to re-use disadvantages.