CAJ | 학술논문

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。
위료감소생물시유제비과정중전통최화제대배경적오염，개발신형고체최화제구유중요의의。해문이섬유소위원료，채용탄화-광화법제비료탄기고체산최화제，병이용SEM（scanning electron microscope）、BET비표면적측시법、XRD（X-ray diffraction）화NH3-TPD（NH3-temperature programmed desorption）대기결구진행표정。연구료탄기고체산최화제최화종려산화갑순통과지화반응제비생물시유적공예조건，고찰료불동순산마이비、반응시간、반응온도급최화제용량대전화솔적영향，병대비료가압조건하탄기고체산최화제여농류산화대갑분광산적최화활성。시험결과표명，당순산마이비10：1，반응온도110℃，반응시간2 h，탄기고체산최화제용량위종려산질량적5%시，전화솔가체도98.11%。재가압조건하，탄기고체산적최화활성고우농류산화대갑분광산，차최화제재사용4차후，전화솔잉재60%이상。통과GC-MS분석득출제비적생물시유갑지질량분수위93.8%。해연구위섬유소기탄기고체산제비생물시유제공료의거。
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 catalyst amount) on esterification efficiency were investigated. Comparison of catalytic activities among carbon-based solid acid catalyst, concentrated sulfuric acid and para-toluenesulfonic acid were conducted under pressure. The results indicated that the optimal molar ratio of methanol to palmitic acid, reaction temperature, reaction time and catalyst amount was 10:1, 110℃, 2h, and 5%(based on the mass of palmitic acid), respectively. The catalytic activity of carbon-based solid acid catalyst was higher than the other two catalysts. In order to evaluate the reusability, the catalyst was recovered for further conversion of palmitic acid under the optimized conditions through simple filtering. The conversion ratio was still above 60% after the catalyst was reused for four times. The gas chromatograph-mass spectrometer was used for analyzing the product oil components. The content of the fatty acid methyl esters in the product oil was 93.8%, which consisted mainly of hexadecanoic acid methyl ester of 11.8%, octadecadienoic acid methyl ester of 26.6%, eicosenoic acid methyl ester of 10.7%, docosenoic acid methyl ester of 10.6%and docosanoic acid methyl ester of 5.8%.