碳基固体酸催化剂加压催化合成生物柴油  

Synthesis of biodiesel using carbon-based solid acid catalyst under pressure

作　　者：司展[1,2,3,4] 蒋剑春[1,2,3,4] 王奎[1,2,3,4] 徐俊明[1,2,3,4] 

机构地区：[1]中国林业科学研究院林产化学工业研究所,南京210042 [2]生物质化学利用国家工程实验室,南京210042 [3]国家林业局林产化学工程重点开放性实验室,南京210042 [4]江苏省生物质能源与材料重点实验室,南京210042

出　　处：《农业工程学报》2014年第1期169-174,共6页Transactions of the Chinese Society of Agricultural Engineering

基　　金：林业公益性行业科研专项经费资助(201204801);国家自然科学基金(31100521)

摘　　要：为了减少生物柴油制备过程中传统催化剂对环境的污染,开发新型固体催化剂具有重要意义。该文以纤维素为原料,采用碳化-磺化法制备了碳基固体酸催化剂,并利用SEM(scanning electron microscope)、BET比表面积测试法、XRD(X-ray diffraction)和NH3-TPD(NH3-temperature programmed desorption)对其结构进行表征。研究了碳基固体酸催化剂催化棕榈酸和甲醇通过酯化反应制备生物柴油的工艺条件,考察了不同醇酸摩尔比、反应时间、反应温度及催化剂用量对转化率的影响,并对比了加压条件下碳基固体酸催化剂与浓硫酸和对甲苯磺酸的催化活性。试验结果表明,当醇酸摩尔比10:1,反应温度110℃,反应时间2 h,碳基固体酸催化剂用量为棕榈酸质量的5%时,转化率可达到98.11%。在加压条件下,碳基固体酸的催化活性高于浓硫酸和对甲苯磺酸,且催化剂在使用4次后,转化率仍在60%以上。通过GC-MS分析得出制备的生物柴油甲酯质量分数为93.8%。该研究为纤维素基碳基固体酸制备生物柴油提供了依据。Due to the environmental pollution caused by the widely use of and the depletion of fossil energy resources, the search for renewable energy has gained worldwide attention. Biodiesel has been considered as an alternativeto conventional fuels, because it is biodegradable and has high cetane number, low aromatic hydrocarbon content and excellent lubrication performance. Traditionally, the catalysts used for the esterification of inedible oil into biodiesel are liquid acids such as sulfuric acid, which is corrosive and difficult to reprocess. To alleviate these problems, a carbon-based solid acid catalyst was developed by the sulfonation of incompletely carbonized cellulose. The cellulose was heated at an 500℃ under N2 flow about 11 hrs to produce incomplete carbonization. The resulting material with 4 g was then ground to powders and heated in 50mL of concentrated H2SO4 （98%） under N2 flow to introduce SO3H into the aromatic carbon rings. The catalyst was characterized by a series of measurements. The layer structure was found from the Scanning Electron Microscope （SEM） image of the prepared carbon material. The BET result showed the catalyst had no pore structure on the SEM image. The powder X-ray diffraction （XRD） pattern of carbon material after the sulfonation showed broad and weak diffraction peaks attributable to amorphous carbon composed of aromatic carbon sheets oriented in a considerably random fashion. The temperature programmed desorption of NH3 （NH3-TPD） profiles showed that the catalyst had two distinct desorption peaks from 100 to 300℃and 750 to 800℃that were assigned to two types of acid sites. The low and high temperature peaks were corresponded to the weak and strong acid sites, respectively. The catalytic performance of the carbon-based solid acid catalyst for the synthesis of biodiesel was investigated via the esterification of palmitic acid and methanol. The effects of reaction conditions （molar ratio of methanol to palmitic acid, reaction temperature, reaction time and c

关 键 词：生物柴油 催化剂 酯化反应 碳基固体酸 

分 类 号：TQ032[化学工程] TK6[动力工程及工程热物理—生物能]