多组分脂肪酸的精馏分离

本介绍了通过混合脂肪酸蒸馏计算来确定多组份的脂肪酸精制分离塔顶及塔釜温度，对于每组份脂肪酸的分离是十分有益的。     

脂肪酸乳化结晶分离的适宜条件

采用乳化结晶分离法对不同组成的脂肪酸的分离进行了研究。主要考察了结晶阶段乳化剂用量R、电解质用量W及稀释水用量RW 对分离结果的影响 ,以及适宜的R、W、RW 及其与组成的关系。研究结果表明 :R、W、RW 具有一适宜值 ,且它们随原料酸中饱和酸质量组成X不同而异。其中R、W分别与X成线性关系 ;RW 与X的关系亦有规律可寻。在适宜条件下进行脂肪酸分离 ,分离效果最好 (液酸产量最高 ,w(液酸 ) >90 % ) ,可满足各行业需要     

混合C4分离制高纯度1—丁烯

论述了混合Ｃ４馏份分离制高纯度－１丁烯的工业生产方法，着重讨论了Ｃ４原料来源及组成，混合Ｃ４分离制高纯度１－丁烯的原则流程及生产过程中的脱丁二烯工艺，脱异丁烯工艺，加氢工艺，脱残余异丁烯工艺、分离精制工艺等。     

生物柴油中C16甲酯与C18甲酯的减压精馏

借助自制玻璃精馏塔,在减压操作条件下研究了麻疯果油制得的生物柴油中C16甲酯与C18甲酯之间的分离提纯特性.自制玻璃精馏塔直径为20 mm,内装不锈钢弹簧填料,高度为1 000 mm,其实际板数采用标准体系甲基环己烷-正庚烷在全回流条件下标定.在此基础上,比较了全回流条件下C16甲酯与C18甲酯的分离按理想体系计算的理...     

脂肪酸分离技术的研究进展

对目前采用的脂肪酸分离的各种方法进行评述，分析了各种分离方法的优缺点和适用范围，指明了目前研究中存在的不足和今后的发展方向。     

C4～C6混合二元酸的分离

介绍了国内外C4～C6混合二元酸分离技术的概况,综述了各种分离与纯化方法及其工艺条件.     

用萃取精馏法分离C4烷烃与烯烃的研究进展

对近年来Ｃ４分离的新进展从溶剂选择,工艺流程改进,计算机模拟,双液相萃取等方面加以论述。     

混合二甲苯分离技术研究进展

混合二甲苯分离技术主要有络合法、常压低温结晶法、精密精馏法等方法。吸附分离法因其具有单程的收率高、分离工艺条件较缓和、无毒性、无腐蚀性、在全部液相操作条件下不需要特定的设备、生产投资小和能耗较低等优点而得以推广。对吸附剂的改性研究可进一步提高分离效果,因此吸附法在分离混合二甲苯方面具有很好的发展趋势。     

Lactose fermentation in the presence of C18 fatty acids

Lactose degradation in the presence of C₁₈ long chain fatty acids was examined under anaerobic conditions at 37 °C. The lactose degradation rate was a function of linoleic acid (LA) and oleic acid (OA) concentrations but independent of the amount of stearic acid (SA) added. In cultures fed with LA, lactose was removed within approximately 12 h and within 6 h for cultures inoculated with OA or SA. Glucose, a product of lactose degradation, was only observed in cultures fed with 500–700 mg dm^?3 LA and 1000 mg dm^?3 OA. No galactose was detected under any of the conditions examined. The cause of glucose accumulation is likely due to inhibition of acidogens by LA and OA. Lactate was detected under all conditions examined. LA was more inhibitory on lactate‐consuming organisms than OA and SA and larger amounts of lactate were observed in cultures fed with LA. In addition to lactate, butyrate, propionate and acetate were also observed. Accumulation of volatile fatty acids was a function of the type and concentration of long chain fatty acids. In cultures fed with SA, lower levels of butyrate and acetate were observed when compared with those inoculated with LA and OA and no propionate was detected. Copyright © 2004 Society of Chemical Industry     

Influence of C18 long chain fatty acids on butyrate degradation by a mixed culture

Butyrate degradation in the presence of C₁₈ long chain fatty acids (LCFAs) was examined under anaerobic conditions at 21 °C. Butyrate degradation rates were a function of linoleic acid (LA) and oleic acid (OA) concentration but independent of the amount of stearic acid (SA) added. Within 2–4 h, butyrate reached undetectable levels in the control cultures. However, in cultures fed with LA, butyrate was removed within between 12 and 25 h and within 2–12 h for cultures inoculated with OA or SA. Propionate was detected in cultures fed with 50 mg dm^?3 LA and in cultures inoculated with OA and SA. LA exerted a greater inhibitory effect on butyrate‐degrading organisms than OA and SA with longer removal times observed in cultures fed with LA. The propionate and acetate removal times and quantity produced were not related to the type and concentration of LCFA. Copyright © 2004 Society of Chemical Industry     

Diffusion coefficients of C18 unsaturated fatty acid methyl esters in supercritical carbon dioxide containing 10% mole fraction ethanol as modifier

To determine the molecular diffusion coefficients of C18 unsaturated fatty acid methyl esters in supercritical carbon dioxide (scCO₂) containing 10 mol% ethanol as a modifier, four methyl esters of C18 fatty acids, i.e., methyl oleate, methyl ricinoleate, methyl linoleate and methyl linolenate were selected as the typical solutes. The diffusion coefficients were measured at temperatures from 313.15 to 333.15 K and pressures from 15 to 27 MPa using the Taylor–Aris chromatographic peak broadening (CPB) technique. The influences of temperature, pressure, density and viscosity of the solvent mixture on the diffusion coefficients were examined. The results show that methyl oleate always diffuses faster than methyl ricinoleate at the same operating condition. Moreover, the D₁₂ values in ethanol-modified scCO₂ decrease with the increase of the number of C-C double bonds in C18-methyl ester, which is consistent with the trend reported in pure scCO₂. The diffusivity data are compared with the estimation of eleven predictive models. The modified Wilke–Chang equation is the best purely predictive model and the free volume model of Dymond with two adjustable parameter gives the least errors with average absolute deviations lower than 2.5%.     

尿素包合法分离棕榈油甲酯化产物中C_(16)和C_(18)脂肪酸甲酯

采用尿素包合法分离棕榈油甲酯化物中不同碳链长度的脂肪酸甲酯,为农产品涂膜保鲜材料的开发提供原料。重点考察了尿素用量、溶剂用量、包合时间和包合温度对分离效果的影响,并以尿素用量、95%乙醇用量、包合温度为三因素,C16脂肪酸甲酯和C18脂肪酸甲酯的纯度为二指标,根据Box-Benhnken中心组合试验设计原理,利用Designexpert7.0.1软件分析优化了分离的工艺条件并建立了回归模型。优化的最佳工艺条件如下:在棕榈油甲酯化物用量为20g,尿素用量为35g,95%乙醇用量为120mL,包合温度为5℃,包合时间为16h的条件下,饱和脂肪酸甲酯相中C16脂肪酸甲酯的含量达78.5%,不饱和脂肪酸甲酯相中C18脂肪酸甲酯的含量达93.1%,分别比原料提高36.4%和40.8%。     

Viscosities of fatty acids, triglycerides, and their binary mixtures

Viscosity data have been obtained as a function of temperature for seven fatty acids (pelargonic, capric, lauric, myristic, palmitic, stearic, and oleic) and four triglycerides (tricaprilin, tripalmitin, tristearin, and triolein) and their binary mixtures at temperatures from above their melting points to 90°C. The viscosity measurements were performed by using Cannon Fenske glass capillary kinematic viscometers. Modified versions of the Andrade equation were used to correlate the kinematic viscosities of pure fatty acids and pure triglycerides. The MacAllister method was used for their binary mixtures. The correlation constants are valuable for designing or evaluating chemical process equipment, such as heat exchangers, reactors, distillation columns, and process piping.     

An improved reversed-phase thin-layer chromatography method for separation of fatty acid methyl esters

Resolution of fatty acid methyl esters (FAME) by thin-layer chromatography often is complicated by co-migration of certain acyl-isomers in heterogeneous mixtures. However, a novel reversed-phase thin-layer chromatography method which employs 10% (wt/vol) silver nitrate in a mobile phase containing acetonitrile/1,4-dioxane/acetic acid (80:20:1, vol/vol/vol) allows one-dimensional resolution of a wide range of acyl-methyl esters. This innovation enables improved separation of saturated FAME ranging from C₁₂ to C₂₂, and geometric isomers of C₁₄ to C₂₂ unsaturated FAME by thin-layer chromatography.     

碳八芳烃异构体分离技术评述

介绍了碳八芳烃异构体工业分离技术的现状、对二甲苯分离技术的新发展。评述了择形催化生产对二甲苯的技术、利用结晶处理高浓度对二甲苯原料、变压吸附低成本浓缩对二甲苯技术、分子筛膜分离对二甲苯等。     

离子液体中结晶分离熊果酸和齐墩果酸研究

为拓展结晶溶剂的范围和提高结晶分离熊果酸和齐墩果酸的性能,引入离子液体作为结晶溶剂。测定了熊果酸和齐墩果酸在六种离子液体+乙醇溶液中的溶解度数据,根据该数据,选取1-辛基-3-甲基咪唑六氟磷酸+乙醇混合溶液作为溶剂对熊果酸和齐墩果酸进行了结晶分离,并采用单因素实验对结晶工艺进行了初步优化。结果表明:在1-辛基-3-甲基咪唑六氟磷酸质量分数5%,熊果酸和齐墩果酸质量比1.5∶1,结晶温度30℃,结晶时间14 h的条件下,结晶产物中齐墩果酸的质量分数可以达到85%左右。