复合溶剂液化制备乙酰丙酸乙酯的碳同位素分馏  

Carbon isotope fractionation of ethyl levulinate by liquefaction of composite solvents

作　　者：沈娟章[1] 程琴 午紫阳 蔡燕燕[1] 谭卫红[1] SHEN Juanzhang;CHENG Qin;WU Ziyang;CAI Yanyan;TAN Weihong(Key Laboratory of Biomass Energy and Material,Institute of Chemical Industry of Forest Products,CAF,Nanjing 210042,China)

机构地区：[1]中国林业科学研究院林产化学工业研究所,江苏省生物质能源与材料重点实验室,南京210042

出　　处：《林业工程学报》2024年第4期99-104,共6页Journal of Forestry Engineering

基　　金：江苏省生物质能源与材料重点实验室面上项目(JSBEM-S-202323)。

摘　　要：利用单体稳定同位素分析(CSIA)技术研究C3、C4植物源原料液化生成乙酰丙酸乙酯(EL)过程中碳稳定同位素分馏特征。实验结果表明,在反应时间15 min内,C3、C4植物源原料液化生成EL的反应速率为木薯淀粉>玉米淀粉,杨木纤维素(P-C)>玉米秸秆纤维素(CS-C),杨木>玉米秸秆,液化生成EL过程中碳同位素比值的分馏速率为C3植物源原料>C4植物源原料,两者之间存在着直接的线性关系,液化反应速率较大时,δ^(13)C值的变化速率也大。结合瑞利方程量化液化过程中EL的^(13)C碳稳定同位素的富集程度,得到不同原料液化过程中富集因子大小为ε>ε,ε_(CS-C)>ε_(P-C),ε>ε,表明液化过程中碳同位素的富集程度与原料的δ^(13)C值相关,液化程度越大,δ^(13)C值变化程度越大,通过追踪反应过程中的碳稳定同位素分馏变化就可以反映其液化程度。此外,^(13)C同位素富集在中间产物5-羟甲基糠醛(5-HMF)上,而在最终产物EL中相对较少;由于动力学同位素效应的存在,发生化学反应后,^(12)C同位素在EL中逐渐富集,^(13)C同位素富集在5-HMF中,说明在试验过程中5-HMF→EL的路径占优势。由此可知,CSIA可用于C3、C4植物源原料液化过程的研究。Compound-specific stable isotope analysis(CSIA)can separate a single compound by gas chromatography or liquid chromatography,in which the stable isotope ratio of the element can be measured by isotope ratio mass spectrometry.It elucidates the transformation process of compounds in chemical reactions by analyzing the stable isotope composition characteristics,variation laws and fractionation principles of specific elements in target compounds.CSIA was used to study the fractionation characteristics of carbon-stable isotopes during the liquefaction of C3 and C4 plant-derived feedstocks to ethyl levulinate(EL).The experimental results showed that,within the 15 min reaction,the reaction rates of C3 and C4 plant-derived feedstocks were as follows:tapioca starch was faster than corn starch,poplar cellulose was faster than corn straw cellulose,and poplar was faster than corn straw.The fractionation rate of EL carbon isotope ratio generated by liquefaction of C3 plant-derived feedstocks was greater than that of C4 plant-derived feedstocks.The results indicated that the differences in carbon stable isotope composition of different feedstocks would affect the reaction rate of liquefaction.There was a direct relationship between the reaction rate and the fractionation rate,when the liquefaction reaction rate was large and the rate of change ofδ^(13)C value was also large.Combined with the Rayleigh equation to quantify the enrichment degree of ^(13)C carbon stable isotope of EL during liquefaction,the enrichment factor in the liquefaction process of different raw materials was obtained as follows:εcorn starch>εtapioca starch,ε_(CS-C)>ε_(P-C),εcorn straw>εpoplar.The results showed that the enrichment degree of carbon isotopes during the liquefaction process was related to theδ^(13)C value of the feedstocks,and the enrichment factor of C4 feedstocks with small carbon isotope ratio was larger.The degree of reaction progress in the liquefaction process was related to the carbon stable isotope of the feedstocks,and the fr

关 键 词：单体同位素分析 乙酰丙酸乙酯 液化 碳同位素分馏 

分 类 号：TQ35[化学工程] TK6[动力工程及工程热物理—生物能]