纤维素溶解体系的研究进展

综述了纤维素无机溶剂及有机溶剂的研究进展,分析比较了各溶剂体系的优缺点。其中有机溶剂中离子液体和N-甲基氧化吗啉的溶解能力最强,无机溶剂中碱/尿素或硫脲/水体系的溶解能力最强。但纤维素在各个溶解体系中都有一定程度的降解。     

溶剂抽提偏三甲苯-正辛烷三元体系液-液相平衡的对比分析

在70℃下采用浊点法分别测定了二甲亚砜、N-甲酰吗啉、四甘醇与偏三甲苯-正辛烷三元体系液-液相平衡数据，得到体系的液-液分层曲线和结点数据，并用液-液分层曲线和体系物性（折光指数、密度）相结合的方法对平衡数据进行了分析。结果表明：溶剂的溶解能力的次序为：N-甲酰吗啉＞二甲驱砜＞四甘醇；溶剂的选择性次序为：二甲亚砜＞四甘醇＞N-甲酰吗啉，三种溶剂中二甲亚砜同时具有较高的溶解能力和选择性，较适合萃取偏三甲苯-正辛烷的混合溶液。研究结果可以为溶剂抽提过程相平衡数据库提供基础数据，并为重芳烃抽提的溶剂选择提供参考。     

偏三甲苯-正辛烷-(环丁砜+N-甲酰吗啉)液-液相平衡研究

在70℃下采用浊点法分别测定了不同质量比的环丁砜和N-甲酰吗啉溶剂与偏三甲苯-正辛烷四元体系液-液相平衡数据,得到体系的液-液分层曲线和结点数据,并用液-液分层曲线和体系物性(折光率、相对密度)相结合的方法对平衡数据进行了分析。结果表明:4种溶剂均具有较高溶解能力,其次序为:1#溶剂>2#溶剂>3#溶剂>4#溶剂,3#溶剂同时还具有较高的选择性,适合萃取偏三甲苯-正辛烷混合溶液。研究结果可以为溶剂抽提过程相平衡数据库提供基础数据,并为重芳烃抽提的溶剂选择提供参考。     

薄层色谱法测定丁苯橡胶的溶解度参数

我们根据由薄层色谱法(下称TLC法)测得的R_f可用以表征溶剂对聚合物的溶解能力的观点,以及由此选择氯丁胶粘剂的两组低毒溶剂的结果,认为如果选择一组可对某高聚物作TLC展开的溶剂体系,它们分别具有不同δ值以构成一个溶解度参数谱,测定它们对高聚物的展开结果,其中R_f最大的溶剂体系对它的溶解能力为最大。     

油品脱硫萃取工艺的溶剂性能研究

为了提高FCC汽油的质量,用溶剂萃取法进行脱硫.用改进的溶解度参数法在不同温度下定量估算萃取溶剂对硫化物的溶解能力和选择性,其中溶解能力与选择性可用无限稀释活度系数表示.选择四种溶剂对模拟体系(正辛烷+苯并噻吩)进行萃取实验,并测定脱硫率与油品回收率,结果表明理论估算结果与实验测定结果基本吻合.兼顾溶剂对硫化物的溶解能力与选择性,在4种溶剂中PEG 400是性能较优的FCC汽油脱硫溶剂.三级错流或逆流萃取总含硫量为1143 μg/g的模拟汽油时脱硫率可达到90%以上.     

环烷基丙酸合成工艺研究

以环戊酮、环己酮和吗啉为起始原料,以磺酸凝胶树脂732为催化剂,分别合成了环戊基吗啉烯胺和环己基吗啉烯胺,然后选择叔丁醇为溶剂,环戊(己)基吗啉烯胺和丙烯酸甲酯进行迈克尔加成反应,生成环戊(己)酮-2-(β-)丙酸甲酯,经钯碳和硫酸还原酮羰基,脱水,水解生成3-环戊(己)基丙酸。主要考察了反应过程中催化剂和溶剂对产品合成工艺的影响。结果表明,以吗啉为有机胺利用磺酸凝胶树脂催化合成烯胺化合物,工艺简单,烯胺收率达98%以上;在迈克尓加成反应中,选用叔丁醇为溶剂,收率达95%以上,溶剂可回收利用;最后采用钯碳和硫酸进行还原反应,产品收率达85%以上。     

无苯溶剂型氯丁胶粘剂的试制

本文根据高分子结构理论,结合极性相近理论和溶度参数理论,利用溶剂的氢键指数v及可溶性参数δ的计算法了介各种溶剂对聚氯丁二烯的溶解能力,然后进行实验,选择了汽油,醋酸乙酯,丙酮组成的三元混合溶剂体系为无苯溶剂,试制成无苯溶剂型氯丁胶粘剂,并在胶中加入 5～10％的固体二甲苯树脂,使胶稳定性好,强度高。     

盐酸吗啉脒胍的合成研究

以吗啉和盐酸为原料合成盐酸吗啉,使其与双氰胺反应制备盐酸吗啉脒胍。重点讨论了原料配比、加料顺序、反应时间及溶剂等因素对合成工艺的影响。研究表明：吗啉：浓盐酸=1．06∶1(摩尔比),合成盐酸吗啉的收率可达98．27％,且加料顺序对反应无明显影响；以二甲苯为溶剂,盐酸吗啉：双氰胺=0．8∶1(质量比),反应时间为3．5h,盐酸吗啉脒胍的收率为97．01％。两步反应总收率可达96．97％。     

甲基环己烷一正庚烷一混合溶剂体系的相平衡及溶剂抽提性能

测定了甲基环己烷一正庚烷一混合溶剂（环丁砜／苯甲醇及环丁砜／Ｎ一甲基一吡咯烷酮）体系在（３５±０．１）和（４５±０．１）℃下的液液分层曲线及各体系的结线数据,并计算得到了混合溶剂的选择性、溶解度等数据．初步讨论了以上混合溶剂体系萃取分离甲基环己烷与正庚烷的基本性能．结果表明,同一温度下质量组成相同的环丁砜／苯甲醇混合溶剂体系的选择性、溶解度等均较环丁砜／Ｎ一甲基一吡咯烷酮混合溶剂体系为优．结合２５℃时的数据,考察了温度对这些溶剂体系的选择性、溶解度等的影响,表明升高温度能提高溶剂的溶解能力,而选择性则有所降低．     

环氧导静电涂料混合溶剂的研究

研究油罐内壁环氧导静电涂料,对保证石油贮罐的安全使用、排除静电荷的积累有着重要意义。不同比例的混合溶剂对环氧导静电涂料的各种性能影响很大,因此,混合溶剂的选择尤为重要。本实验选用二甲苯和正丁醇作为环氧树脂的混合溶剂,研究不同比例的混合溶剂对环氧树脂溶解能力的影响,以及对漆膜导静电性能、耐油性能的影响。结果表明:二甲苯与正丁醇按质量比1:1配制的混合溶剂对环氧树脂E-20具有较强的溶解能力,且制备的漆膜具有优异的导电性和耐油性。     

四氢萘/甲苯混合溶剂中硫璜的溶解特性

为解决硫磺溶解过程中溶剂种类选择少、溶解度低的问题,从溶剂分子结构出发选用四氢萘和甲苯混合溶剂在60~99℃、5~30 min、四氢萘与甲苯质量比(MROTTT)1~15参数范围内进行硫磺溶解实验。通过对四氢萘、甲苯单体及二者复合溶剂对硫磺的溶解性对比分析,结果表明,在温度83℃、时间7 min、MROTTT为15时,混合溶剂对硫磺的溶解度最大,达到14.17 g/100 g混合溶剂。     

废旧涤棉面料组分溶解分离研究

采用离子液体[Amim]Cl对废旧涤棉混纺面料中含棉成分进行溶解回收。通过正交试验法,研究了温度、[Amim]Cl质量分数、时间、溶质与溶剂比例等因素对溶解过程的影响,得到优化的溶解工艺条件,同时研究了溶剂对涤纶的影响。结果表明:处理后的面料中接近99.2%的棉纤维被溶解,而涤纶没有明显损伤。影响棉纤维溶解效果因素的主次关系依次为:溶解温度,溶解时间,[Amim]Cl质量分数,溶质与溶剂质量比。优化的溶解工艺参数为:溶解温度95℃,溶解时间5 h,[Amim]Cl质量分数99%,溶质与溶剂质量比0.2∶3.5。红外分析表明:溶解处理的样品中棉的特征峰基本消失。     

Properties of hydrogels of atactic poly(vinyl alcohol)/NaCl/H2O system and their application to drug release

In order to prepare cost‐effective physically cross‐linked hydrogels including food salt sodium chloride, samples, were prepared with various concentrations of NaCl and respective atactic poly(vinyl alcohol) (a‐PVA), and were evaluated. It had been observed that hydrogels containing NaCl concentration (9–11 wt%) along with a‐PVA concentration 9–5% respectively exhibited higher melting points (91.5–95.1 °C). A higher melting point characterizes the hydrogel composition of a system like a‐PVA(7%)/NaCl(11%)/H₂O. The swelling degree of this hydrogel was found to be comparatively better at 37 °C than at any other temperature studied here. However, irregular Fickian swelling was found at this temperature. The UV light absorption maximum at 362–364 nm and minimum at 351 nm for this hydrogel had been found as evidence of physical cross‐linking. A drug, theophylline was loaded by solvent‐sorption and feed‐mixture dissolving methods. The feed‐mixture dissolving method is better than solvent sorption because of high drug loading, comparatively low fraction release rate and more sustained‐release of drug than that of solvent‐sorption. Theophylline was released twice as fast from the hydrogel after solvent‐sorption drug loading (3 h) than from that which used the feed‐mixture dissolving method (6.5 h). Theophylline‐loaded hydrogels of this system (feed‐mixture dissolving) were then prepared at high temperature (60 °C) thawing for 6 h followed by chilling at 0.4 °C for 3 h as one cycle. And the drug release behaviour and mass transfer were found almost the same as for chilling (24 h at 0.4 °C)–thawing (48 h at room temperature). Drug release behaviour was studied as apparently irregular Fickian diffusion (Higuchi Matrix Dissolution Model). © 2002 Society of Chemical Industry     

Selectivity of Supercritical CO<Subscript>2 </Subscript>in the Fractionation of Hake Liver Oil Ethyl Esters

The solubility of different ethyl esters derivatized from hake liver oil in supercritical carbon dioxide was studied. A selectivity factor was used to determine optimal conditions to fractionate the ethyl ester mixture. A strong influence of solvent pressure and temperature was observed within 8.63–18.04 MPa and 40–70 °C. The lowest total solubility of the ethyl ester mixture was obtained when using supercritical carbon dioxide at the lowest density (the lowest pressure and the highest temperatures value tested). The highest discrimination against long-chain polyunsaturated fatty acids (e.g. EPA and DHA) was also obtained at these above conditions. Conversely, higher solubility and lower selectivity were obtained when solvent density increased. Considering this inverse correlation between selectivity and solubility, a single-step batch-fractionation process was designed to increase the 22:6 ethyl ester content from an initial value of 17.5% in the starting material to 55% in the final extract.     

溶剂对电纺聚酯纳米纤维可纺性的影响

利用静电纺丝法制备聚酯(PET)纳米纤维,选择苯酚和四氯乙烷,三氟乙酸,三氟乙酸和二氯甲烷3种溶剂分别溶解PET切片进行静电纺丝,通过扫描电子显微镜(SEM)对纤维表面形态进行观察,结果表明:三氟乙酸和二氯甲烷混合溶剂溶解PET制备的电纺纤维较好。使用视频光学接触角测定仪测试PET电纺纤维膜与其流延膜的接触角,通过分析两者表面结构,证明PET电纺纤维膜能产生较强的疏水功能。     

共混聚合物体系的静电纺丝及其混容性研究

分别将聚醚砜酮(PPESK)/聚苯乙烯(PS)不相容体系溶于N,N-二甲基乙酰胺或N-甲基吡咯烷酮与四氢呋喃的混合溶剂,聚甲基丙烯酸甲酯(PMMA)/聚丙烯酸甲酯(PMA)相容体系溶于丁酮,搅拌得到聚合物共混溶液进行静电纺丝和浇铸成膜。研究了浇铸膜与电纺纤维膜的微观结构与力学性能。结果表明:静电纺丝改善了不相容体系的混容性,而未改变相容体系的混容性;溶剂对电纺纤维的微观结构以及力学性能有所影响。     

Separation of organic solvent from dilute aqueous solutions and from organic solvent mixtures through crosslinked acrylate copolymer membranes by pervaporation

The composite membranes of acrylate polymers and porous substrate were prepared. The separation of the organic solvent–water mixtures and the organic solvent–organic solvent mixtures through these membranes by pervaporation was investigated. The acrylate copolymer membrane showed the organic solvent permselectivity for the separation of the organic solvent–water mixture, especially for the chlorinated hydrocarbon–water mixture separation. The high organic solvent permselectivity should be governed by solubility selectivity. The influence of the ester residue of acrylate on the phenol–water mixture separation was observed. The copolymerization of the macromonomers containing the polystyrene, poly(methyl methacrylate), and polydimethylsiloxane chain had a small effect on the separation of the chlorinated hydrocarbon–water mixture. High flux and low selectivity of organic solvent were observed in the case of the organic solvent mixture separation through the n-butylacrylate membrane. The difference of permeability of organic solvent was observed for the acrylate copolymer which has various structures of ester residue. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 69: 1483–1494, 1998     

溶剂对静电纺PA6纤维可纺性的影响

分别用甲酸、六氟异丙醇(HFIP)或甲酸与醋酸(HAc)、N,N-二甲基甲酰胺(DMF)、HFIP的混合溶剂溶解聚己内酰胺(PA6),通过静电纺丝法制备了纳米级的PA6纤维。结果表明:甲酸作为溶剂时,PA6可纺丝溶液质量分数为8%～22%,所纺出的PA6纤维直径为50～300 nm;HFIP作为溶剂时PA6可纺丝溶液质量分数为8%～18%,纤维直径为50～500 nm;甲酸与HFIP,HAc,DMF的混合溶剂对纺丝状态及纤维直径分布的影响均表现为随第2种溶剂的加入,纤维直径的分布变广,平均直径增加;HAc的加入能提高PA6溶液的可纺性。     

Über den Einfluß der Knäuelung der Makromoleküle auf den Reaktionsverlauf in Lösung

The theory of Flory is extended to include the polycondensation in solution. The rate of the process is shown to be affected by the reactivity of the functional groups and their accessibility, considered to be the probability of interactions resulting in reactions. The accessibility depends strongly on the degree of coiling of the reactants. Calculations were performed to test the concept of the dependence of the polycondensation in solution on the chain length of the polymer and the nature of the solvent. The activation energy was found to increase with the degree of coiling of the reactants. The model reaction of 2, 2-bis-(p-hydroxyphenyl)propane with phenyl chloroformate and the polycondensation of 2,2-bis-(p-hydroxyphenyl)propane with its bis-chloroformate were investigated in the mixed solvents nitrobenzene/decaline and nitrobenzene/p-dichlorobenzene. With the first solvent the polarity and the dissolving quality decrease with increasing content of decaline. In the second mixture only the polarity changes with the content of dichlorobenzene. The rate of the model reaction is hardly affected by the composition of the solvent mixture. In the polymer system the rate is likewise hardly affected if only the polarity of the solvent mixture is changed. Lower dissolving quality caused differences of the kinetic constants ranging over one order. The results seem to support the theoretical considerations.