基于液气射流技术改进单宁酸氧化制备鞣花酸的工艺

针对鞣花酸在实际生产过程中耗时长、纯度低等问题，以单宁酸为基质采用液气射流氧化法制备鞣花酸，考察了金属离子、单宁酸浓度、反应温度和反应时间对鞣花酸得率及纯度的影响。进一步探究了溶剂法、结晶法、碱溶酸沉法、反溶剂法对鞣花酸纯度的影响，并通过高效液相色谱、红外光谱、紫外可见分光光谱和热重对鞣花酸高纯度的样品进行表征。结果表明，其制备的较优工艺条件为：2.5%单宁酸溶液中引入金属离子Na （即NaOH）调节反应液pH至8.5，反应温度20℃，反应时间6 h，该条件制备的鞣花酸经碱溶酸沉后产率为46.72%、纯度84.55%；选取甲醇溶剂洗涤法在65℃条件下处理1h，鞣花酸的纯度达98.13%，回收率为75.03%，提高了鞣花酸的热稳定性。液气射流氧化法与溶剂洗涤法相结合，大幅缩短制备鞣花酸的反应时间并明显提高其纯度，有望在工业生产中提高鞣花酸的生产效率并拓宽其在医药和化妆品领域的应用。     

PBS/鞣花酸酯化物复合材料的性能研究

利用五倍子单宁酸氧化制备鞣花酸,通过响应曲面法优化了合成工艺。采用乙酰氯对其进行外酯化,并与可生物降解材料聚丁二酸丁二酯(PBS)复合,探讨了鞣花酸酯化物(EAE)对PBS结晶形态、热稳定性、力学性能和亲疏水性的影响。结果表明,鞣花酸合成的最佳工艺条件为过硫酸铵0.6 g、碱溶p H=9、反应时间24 h,在此条件下鞣花酸的产量为1.34 g/10 g五倍子粉末。傅里叶变换红外光谱(FTIR)分析表明,鞣花酸及其酯化物均为目标合成物。复合材料FTIR分析表明EAE与PBS只进行了物理共混,两者相似相容。同时,EAE对PBS起到了成核剂的作用,使得复合材料的球晶尺寸变小,热稳定性、拉伸强度、疏水性较PBS均有所提高,断裂伸长率相应降低。     

鞣花酸的稳定性及其保护研究

使用乳化法提高了鞣花酸的分散性,并研究了鞣花酸水溶液和乳液在不同处理温度、紫外光照射及部分介质溶液中的稳定性。结果表明,鞣花酸水溶液在存放过程中稳定性逐渐下降,高的处理温度、紫外光照射及无机盐NaCl、羧基纤维素纳等添加剂均不利于鞣花酸水溶液的稳定性,甘油、β-环糊精等添加剂则有利于提高鞣花酸水溶液的稳定性,鞣花酸经过乳化后可提高鞣花酸在存放过程中的稳定性。     

紫外分光光度法测定鞣花酸含量的研究

研究了用紫外分光光度法测定鞣花酸含量的一种新方法。其技术关键是将鞣花酸试样溶于适量稀碱配制分析试液,从而解决了鞣花酸不溶于水和难溶于多数有机溶剂的难题。确定了鞣花酸的紫外特征吸收峰的测定波长为 357 nm;验证了新方法在测定条件下试液浓度与吸光度之间的线性关系,并测算了测量误差;进行了新方法测定值的稳定性试验。研究结果表明,该方法具有操作较为简便、耗用溶剂少、分析成本较低、测定结果误差小等特点,适用于鞣花酸工业生产质量监控的产品含量分析。     

超声提取协同大孔树脂吸附法分离倍花单宁酸

采用超声辅助提取协同大孔树脂吸附法分离倍花单宁酸,考察了吸附树脂用量、pH值、吸附温度和吸附时间对单宁酸提取率的影响。结果表明,吸附液pH为6,添加2 g大孔树脂,50℃下吸附90 min,倍花中单宁酸的提取率为20.56%。     

鞣花酸对人胃癌细胞SGC7901的作用研究

目的通过不同浓度的鞣花酸对SGC7901细胞的作用效果观察,研究鞣花酸对人胃癌细胞的作用效果。方法用SRB法、形态学观察方法检测不同浓度的鞣花酸对SGC7901细胞的作用效果。结果 SRB结果显示鞣花酸浓度在5~40μg/m L内,对胃癌细胞SGC7901的杀伤明显,其作用效果跟药物的作用时间呈正相关,在48 h的作用效果较佳;形态学观察显示,不同浓度的鞣花酸对SGC7901细胞作用效果不同,在浓度达到40μg/m Ll时效果明显。结论鞣花酸对SGC7901细胞有明显的抑制作用。     

聚乙烯醇/鞣花酸共混物的制备及性能

采用了一种天然多酚类物质(鞣花酸)作为自由基捕获剂,并研究了鞣花酸对聚乙烯醇(PVA)热稳定性的影响。通过用傅里叶变换红外光谱仪、差示扫描量热仪、热重分析仪、万能试验机对PVA/鞣花酸共混物的红外吸收、熔点、热失重率以及PVA共混物薄膜的力学性能进行测试和表征。结果表明,鞣花酸可以显著提高PVA的热稳定性,改善了材料的柔韧性和提高断裂伸长率,降低了PVA的熔点。当鞣花酸含量为1.0%时,改善PVA热稳定性的同时使材料保持优异的力学性能。     

由五倍子萃取液中的单宁酸制取鞣花酸的液相色谱分析

以五倍子为原料，在浸取单宁酸的基础上，可以在不同的条件下制取鞣花酸。建立了一种快速、准确、简便的高效液相色谱分析萃取物的方法，可用于生产全过程的检测，随时鉴定萃取物中的有效成分．也可分析最终产品。     

表面活性剂对鞣花酸的增溶及其抗氧化性能研究

主要研究了4种吐温系列非离子表面活性剂对鞣花酸的增溶作用,其中以Tween-20的增溶效果最好。随Tween-20溶液浓度的增大,鞣花酸增溶量逐渐增大,但Tween-20溶液浓度达到10.00 g/L以上时,鞣花酸增溶量则呈现逐渐下降的趋势。35℃时鞣花酸在10.00 g/L的Tween-20溶液中的增溶浓度达到238.59 mg/L,比鞣花酸饱和水溶液浓度(10.12 mg/L)大了近24倍。随着温度的提高,鞣花酸在Tween-20溶液中的增溶量也略有升高。鞣花酸Tween-20增溶体系对ABTS·和DPPH·的清除率IC₅₀分别为0.31 mg/L和0.92 mg/L,而Vc对ABTS·和DPPH·的清除率IC₅₀则为3.32 mg/L和2.40 mg/L。结果表明在表面活性剂的作用下,大幅提高了鞣花酸的增溶量,而且同时保持了鞣花酸优异的抗氧化性能。通过粒径分析和透射电镜实物验证,鞣花酸Tween-20增溶体系的平均粒径为(272.5±3.62)nm。     

鞣花酸的检测及其在化妆品中的应用

综述了鞣花酸的检测方法及其在化妆品中的应用。重点比较了植物样品中鞣花酸测定的不同前处理和高效液相色谱方法以及如何将上述方法借鉴到化妆品中鞣花酸的检测之中,并概述了液相色谱-质谱法定性确证的技术;介绍了鞣花酸在化妆品中的使用情况和其美白、抗老化和收敛等作用;最后展望了化妆品中鞣花酸的应用前景。     

Fatty acid monoesters of 1-ascorbic acid and d-isoascorbic acid

Summary Fat-soluble fatty acid monoesters of 1-ascorbic acid (vitamin C) and d-isoascorbic acid have been prepared from lauric, myristic, palmitic, and stearic acids in 40–50 per cent yields. Evidence has been presented to show that only the primary hydroxyl group of each of the ascorbic acids has been esterified. Antioxidant properties of these esters are being studied. Preliminary tests on the esters have indicated that they may have useful properties as interfacial modifiers.     

Electrosynthesis of 2,3-dimethyltartaric acid from pyruvic acid in acid medium

This study reports the electrohydrodimerization of pyruvic acid to 2,3-dimethyltartaric acid in sulphuric acid medium (0.5 M H₂SO₄) on a lead cathode. The main products detected were lactic acid and 2,3-dimethyltartaric acid. The selectivity towards the formation of 2,3-dimethyltartaric acid was studied vs. pyruvic acid concentration in sulphuric acid solution, at −1.1 V vs. MSE. The best selectivity of 2,3-dimethyltartaric acid reached 69% for an initial concentration of 1.7 M pyruvic acid. The yield of pyruvic acid was 84%.     

Conjugated linoleic acid production from linoleic acid by lactic acid bacteria

After screening 14 genera of lactic acid bacteria, Lactobacillus plantarum AKU 1009a was selected as a potential strain for CLA production from linoleic acid. Washed cells of L. plantarum with high levels of CLA production were obtained by cultivation in a nutrient medium with 0.06% (wt/vol) linoleic acid (cis-9,cis-12-octadecadienoic acid). Under the optimal reaction conditions with the free form of linoleic acid as the substrate, washed cells of L. plantarum produced 40 mg CLA/mL reaction mixture (33% molar yield) from 12% (wt/vol) linoleic acid in 108 h. The resulting CLA was a mixture of two CLA isomers, cis-9,trans-11 (or trans-9,cis-11)-octadecadienoic acid (CLA1, 38% of total CLA) and trans-9,trans-11-octadecadienoic acid (CLA2, 62% of total CLA), and accounted for 50% of the total FA obtained. A higher yield (80% molar yield to linoleic acid) was attained with 2.6% (wt/vol) linoleic acid as the substrate in 96 h, resulting in CLA production of 20 mg/mL reaction mixture [consisting of CLA1 (2%) and CLA2 (98%)] and accounting for 80% of total FA obtained. Most of the CLA produced was associated with the cells (ca. 380 mg CLA/g dry cells), mainly as FFA.     

乳酸催化制备丙烯酸反应液中乳酸和丙烯酸含量的联合测定

以正丁醇为内标,氢火焰离子化检测器测定,建立了气相色谱法直接进样测定乳酸催化制备丙烯酸反应液中乳酸和丙烯酸含量的方法。在载气（N2）流速为30mL·min^-1,氢气流速为88mL·min^-1,空气流速为300mL·min^-1,进样器和离子室温度为160℃,柱温为150℃的10％PEG-20M（3m×3mml填充柱上能实现很好的分离。乳酸和丙烯酸测定方法的线性相关系数分别为0．9994和0．9996,相对标准偏差分别为O．74％和0．56％,平均回收率分别为97．35％-1197．60％,检出限分别为8．62mg·L^-1和1．21mg·L^-1方法简便、快速、准确。     

由氯乙酸副产盐酸精制高纯盐酸

开发研究了氯乙酸副产盐酸的精制工艺及盐酸中有机杂质的紫外分光光度分析方法。副产盐酸经酸洗、吸收、蒸馏得高纯盐酸。中试结果表明 ,工艺合理 ,精制盐酸达到GB 32 0 - 93规定的工业用合成盐酸标准     

炼厂酸性气制取硫酸生产总结

介绍炼厂酸性气制硫酸装置的工艺过程。由于实供气源与设计值有较大出入,二氧化碳浓度偏高, 并且夹带烃类物质较多,使装置无法正常运行。通过对酸性气进行预处理后,一次开车成功,各项工艺指标均达到设计要求,遇酸性气流量突降时可补充适量硫磺,维持正常生产。     

The performic acid oxidation of linoleic acid

The performic acid oxidation of linoleic acid has been shown to form 9,12-dihydroxy-trans-10,11-methylene-heptadecanoic acid (I) after hydrolysis of the formate ester. A sequence of reactions led to the identification of dimethyl-trans-1,2-cyclopropanedicarboxylate by gas liquid chromatography. Spectroscopic evidence is presented for thetrans geometry in I. Failure of the monoepoxide of linoleic acid to give the formate ester of I suggests the alternative that a homoallylic carbonium ion is formed directly upon attack of the peroxide reagent.     

Electrosynthesis of iminodiacetic acid from nitrilotriacetic acid

The electrosynthesis of iminodiacetic acid by electrooxidation of nitrilotriacetic acid in undivided cells has been studied using Zn, Cu, PbO₂, DSA^®O₂, DSA^®Cl₂, C, Ni and porous carbon as anodes. Results show that the synthesis is possible in both acid and basic mediums. The best results were obtained in aqueous 40% w/w sulphuric acid with porous carbon RVC-4000 as anode and SUS 316 as cathode, at 60 °C, 400 mA cm^-2 and charge 95% of theoretical. Under these conditions, nitrilotriacetic acid conversion was 92%, current efficiency 80% and selectivity 85%. Loss of selectivity was due to chemical side reaction between iminodiacetic acid and HCHO electrogenerated in the electrolysis.