四氯化锡催化合成己二酸二丁酯

应用五水四氯化锡催化己二酸和正丁酯的酯化反应，合成了己二酸二丁酯。研究结果表明，五水四氯化锡具有较高的催化活性。考察了己二酸／正丁醇摩尔比和催化剂用量对酯产率的影响，在适宜反应条件[n(己二酸)：n(正丁醇)：n(四氯化锡)＝1：8：0．114，回流反应60min]下，己二酸二丁酯的产率为96．9％。     

SiO2气凝胶负载无水四氯化锡催化顺酐与正丁醇酯化反应的研究

通过表面反应制备了气凝胶SiO2负载无水四氯化锡催化剂并应用于顺酐与正丁醇的酯化反应.结果表明,酯化产物主要为马来酸二丁酯(DBM)与富马酸二丁酯(DBF),其优化条件为:载体SiO2气凝胶焙烧温度500℃,物料摩尔比顺酐∶正丁醇:催化剂=1∶2∶0.0028,反应时间6 h.并且通过XRD,FTIR,DRUV-vis,N2物理吸附以及元素分析技术对所合成催化剂进行表征.结果表明:无水四氯化锡成功负载于SiO2气凝胶表面,在催化酯化反应当中实现了86.1%的顺酐转化率,此结果接近于国内外所报道的均相体系成果,同时在催化回收利用六次后,其活性虽逐步下降,但仍是空白的2倍.分析测试表明,反应过程中Cl的流失量较大、反应物及产物在催化剂表面产生了吸附,这些可能是导致催化活性下降的主要原因.     

氨基磺酸催化合成丁二酸二丁酯

研究了氨基磺酸代替硫酸作为酯催化剂,由丁二酸与正丁醇合成丁二酸二丁酯的反应,考察了反应的影响因素及氨基磺酸的重复使用性能。丁二酸3．0g(250mmol),n(丁二酸)：n(正丁醇)：n(氨基磺酸)=1．00：8．00：0．31,回流分水60min,酯收率97．4％。另外,还催化合成了癸二酸二丁酯、己二酸二丁酯和马来酸二丁酯。     

磷钨酸催化合成癸二酸二丁酯

用磷钨酸催化合成癸二酸二丁酯，考察了诸因素对酯化率的影响，产品经IR鉴定。确定酯化反应的最佳条件为：癸二酸50mmol，n(癸二酸)：n(正丁醇)=l：4，催化剂0．5g(反应物总质量的1．7％)，反应时间2h，酯化率达96．46％。     

四氯化锡催化合成乙酸松油酯

以四氯化锡为催化剂,松油醇和乙酸酐为原料合成乙酸松油酯。最佳反应条件为:松油醇50 mmol,n(松油醇)∶n(乙酸酐)=1.0∶1.4,四氯化锡250 mg,于30℃反应5 h。在最佳反应条件下,松油醇的转化率为94.1%,乙酸松油酯的选择性为93.3%。     

五水四氯化锡催化合成氯乙酸正丁酯

在五水四氯化锡存在下,由氯乙酸和正丁醇合成了氯乙酸正丁酯。实验结果表明,五水四氯化锡对酯化反应具有较高的催化活性。较适宜的反应条件为：氯乙酸100mmol,n(氯乙酸)：n(正丁醇)：n(五水四氯化锡)=1：1．5：0．029,回流分水90min,酯化率91．3％。     

微波协同离子液体催化合成马来酸二丁酯

以马来酸酐和正丁醇为原料,用微波协同离子液体[HSO3-pmim]+[HSO4]-催化合成了马来酸二丁酯。通过单因素实验和正交试验考察催化剂种类、催化剂用量、马来酸酐与正丁醇物质的量比、微波功率、微波时间对马来酸二丁酯产率的影响。实验结果表明,马来酸二丁酯最佳合成条件为:马来酸酐与正丁醇物质的量比1∶4,以离子液体[HSO3-pmim]+[HSO4]-为催化剂,其用量为2.0g,微波功率为600W,微波时间为15min,马来酸二丁酯产率可达到99.36%。在微波辐射下,催化剂离子液体[HSO3-pmim]+[HSO4]-重复使用7次后活性没有明显降低,马来酸二丁酯产率仍高于96%,表明该催化剂具有较好的反应活性和稳定性。与常规加热方式相比,微波加热提高了反应效率,缩短了反应时间。     

氯化铁催化合成癸二酸二丁酯的研究

癸二酸二丁酯是无色透明的液体,具有水果香味和淡的油脂气味,它可作主增塑剂和一些树脂和橡胶的溶剂,由于本品无毒,在食品工业上可用于食品接触的包装材料,也可用于配置水果香精.它通常是在硫酸作催化剂的条件下由癸二酸和正丁醇酯化反应而得[2] ,但硫酸腐蚀性很强,化学性质很活泼,反应中副反应较多,且后处理复杂,收率不高.因此国内外许多化学工作者都在探索用更佳的催化剂取代硫酸.俞善信等发现氯化铁(FeCl3·6H2O)是催化合成低级脂肪酸酯的良好催化剂[3,4],它具有原料易得,酯化活性高,操作方便,后处理简单,腐蚀性低等优点.本文采用氯化铁作催化剂合成癸二酸二丁酯,讨论了影响反应的因素,在适当的条件下酸的转化率可达96.73%.     

顺丁烯二酸酐-癸二酸二丁酯二元体系等温气液平衡

利用改进的沸点仪测定了顺酐-癸二酸二丁酯二元体系在413.15, 433.15和453.15 K下的等温气液平衡数据以及纯癸二酸二丁酯和顺酐的饱和蒸气压数据. 通过与文献值对比, 验证了此方法的可靠性. 同时, 将实验数据回归得到了纯癸二酸二丁酯和顺酐的Antoine常数. 利用NRTL方程进行了气液平衡数据的关联推算, 得到了顺酐-癸二酸二丁酯二元体系的NRTL模型参数. 利用UNIFAC基团贡献法对实验数据进行了预测, 其结果与实验值及运用NRTL方程拟合的结果吻合较好.     

3,4—亚甲二氧基苯甲酸锡酯的合成及表征

３，４－亚甲二氧基苯甲酸及其取代物与三苯基氢氧化锡或二丁基化锡反应合成了５个锡酯，通过元素分析，ＩＲ和＾１ＨＮＭＲ对其进行了表征。     

氧化亚锡催化酯化反应

锡的氧化物的催化作用较少报道,较成功的有使用氧化锡与氧化铬组成的二元催化剂催化氧化,氧化亚锡催化硝基苯还原及交酯的聚合。但用于催化酯化,只有用特定方     

Mechanical and shape‐memory properties of poly(mannitol sebacate)/cellulose nanocrystal nanocomposites

Polyesters based on polyols and sebacic acid, known as poly(polyol sebacate)s (PPS), are attracting considerable attention, as their properties are potentially useful in the context of soft‐tissue engineering applications. To overcome the drawback that PPSs generally display rather low strength and stiffness, we have pursued the preparation of nanocomposites based poly(mannitol sebacate) (PMS), a prominent example of this materials family, with cellulose nanocrystals (CNCs). Nanocomposites were achieved in a two‐step process. A soluble, low‐molecular‐weight PMS pre‐polymer was formed via the polycondensation reaction between sebacic acid and D‐mannitol. Nanocomposites with different CNC content were prepared by solution‐casting and curing under vacuum using two different profiles designed to prepare materials with low and high degree of crosslinking. The as‐prepared nanocomposites have higher stiffness and toughness than the neat PMS matrix while maintaining a high elongation at break. A highly crosslinked nanocomposite with a CNC content of 5 wt % displays a sixfold increase in Young's modulus and a fivefold improvement in toughness. Nanocomposites also exhibit a shape memory effect with a switch temperature in the range of 15 to 45 °C; in particular the materials with a thermal transition in the upper part of this range are potentially useful for biomedical applications. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3123–3133     

Lewis acid-base titrations employing megacycle-frequency oscillators : Titration involving stannic chloride in acetonitrile and benzene solution

By using a megacycle-frequency oscillator to follow the reaction, the Lewis acid, stannic chloride, can be titrated with nitrogen bases in acetonitrile as solvent and with oxygen bases in benzene as solvent with an error of 0.5–4%; reverse-order titrations were equally successful. The characteristic maxima and minima in the titration curves indicate that in acetonitrile stannic chloride probably forms AB, A3B4 and A4B3 adducts with piperidine, and AB and A4B3 adducts with pyridine; no adduct was indicated for diphenylamine. In benzene solution, stannic chloride forms (a) AB2 adducts with MeOH, EtOH, n-PrOH, iso-PrOH, n-BuOH, sec.-BuOH and iso-BuOH, (b) AB and AB2 adducts with acetone and tetrahydrofuran, and (c) an AB adduct with dioxane; the stoichiometry for a group of ethers is less decisive. The presence of the 1:1 tetrahydrofuran-stannic chloride adduct in benzene supports the belief that pentacoordinate tin exists in certain adducts with oxygen bases. The megacycle-frequency oscillator was also applied to the estimation of the relative base strength of Lewis bases toward a given Lewis acid by assuming that the instrument response increase, as an ether or alcohol was added to stannic chloride in benzene, is due to the formation of the new coordinate bond. Agreement of the data obtained with the limited existing data on relative base strengths of ethers is good in those cases where comparable steric factors are involved.     

Cationic polymerization of vinyl compounds in the presence of tetra-n-butylammonium salts

The effects of salts were examined in cationic polymerization of vinyl compounds. Cationic polymerization of styrene was carried out at 0°C, with acetyl perchlorate, stannic chloride, stannic chloride–trichloroacetic acid and boron trifluoride etherate as catalysts. Tetra-n-butylammonium perchlorate, fluoroborate and iodide were used as salts. The presence of small amounts of the salts changed both the polymerization rate and the molecular weight of polymer considerably. The consideration of various effects led to the conclusion that the results are explicable principally on the basis of counterion exchange. To confirm this, the copolymerization of 2-chloroethyl vinyl ether with γ-methylstyrene was investigated at ?78°C. The copolymer composition curve when stannic chloride was used as catalyst was changed and coincided with that of polymer obtained with acetyl perchlorate catalysis when the perchlorate salt was added. This supports the concept of counterion exchange.     

SYNTHESIS AND AVERAGE SEQUENCE LENGTH DETERMINATION OF AROMATIC-ALIPHATIC COPOLYESTERS CONTAINING POLY(ALKYLENE OXALATE) UNITS

Two series of aromatic-aliphatic random copolyesters(PEBTOXS)with diverse diol ratios have been synthesized by direct melting polycondensation.Two kinds of diols(glycol(EG)and 1,4-butanediol(BD))are used in combination in order to adjust crystallization and tensile properties,and three kinds of diacids(dimethyl terephthalate(DMT),diethyl oxalate(DEOX),and sebacic acid(SA))are involved.~1H-NMR spectra quantify both composition and structure,and show that the final contents in copolyesters appropriate to t...     

癸二酸己二醇酯/己二酸二醇酯共聚物的合成及热性能

癸二酸己二醇酯/己二酸二醇酯共聚物的合成及热性能;直接聚合;可降解聚合物     

Synthesis of New Aza Thia Crowns Bearing 2,2′-Diaminodiphenyl Disulfide

Abstract

New aza thia crowns were prepared from the reaction of 2,2′-diaminodiphenyl disulfide and diacids or diacid chlorides. Diacids are malonic acid, adipic acid, sebacic acid, and 2,2′-thiodiacetic acid and diacid dichlorides are malonyl chloride, adipoyl chloride, sebacoyl chloride, and 2,2′-thiodiacetyl chloride.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional figures.]     

Friedel-crafts polymerisations with α,α′-dimethoxy-p-xylene—I The initiation step with stannic chloride as catalyst

A white insoluble 1:1 complex is formed between stannic chloride and α,α′-dimethoxy-p-xylene (DMPX) when the Friedel-Crafts copolymerisation of DMPX and benzene is carried out in a series of solvents using stannic chloride as catalyst. As the reaction proceeds, the precipitate dissolves, being converted to a 1:1 and later a 1:2 complex of stannic chloride and methanol, the latter being a product of the reaction. The 1:1 stannic chloride:methanol complex is an active catalyst for the polymerisation while the 1:2 complex is relatively inactive. The rate of the reaction is also strongly dependent upon the dielectric constant of the medium.For these reasons, a precise quantitative investigation of the kinetics of the polymerisation will be almost impossible but experimental conditions are specified whereby a partial investigation may be made for comparison with the SnCl₄/benzene/di(chloromethyl) benzene system previously studied.     

Polymerization of coordinated monomers. XII. Alternating copolymerization of γ-crotonolactone with styrene with the use of stannic chloride

γ-Crotonolactone and styrene copolymerize alternately in the presence of stannic chloride at -10°C under photoirradiation. The intrinsic viscosity of the resulting copolymer is in the range of 0.6–0.8 dl/g at 30°C in chloroform. The equilibrium constants for the complex formation between stannic chloride and γ-crotonolactone were determined in 1,2-dichloroethane-toluene solution at 0 and ?20°C by use of absorption band at 350 nm. Continuous variation plots based on the ¹H-chemical shift show a 1:1 interaction between styrene and the γ-crotonolactone coordinated to stannic chloride. The equilibrium constants for the ternary molecular complex formation between the coordinated γ-crotonolactone and styrene were determined in 1,2-dichloroethane in the temperature range from ?20 to 0°C. The equilibrium constants, derived independently from the measurements of the nonequivalent protons in γ-crotonolactone, are equal to each other within the experimental error. The mechanism of the alternating copolymerization of γ-crotonolactone and styrene in the presence of stannic chloride is discussed in terms of the homopolymerization of the ternary molecular complex.