新品研发辑要

N-甲酰-α-L-天冬氨酰-L-苯丙氨酸的合成简介:N-甲酰二-L-天冬氨酰-L-苯丙氨酸是合成阿斯巴甜〔Aspartame,化学名称:α-L-天冬氨酰-L-苯丙氨酸甲脂〕的中间体。阿斯巴甜相比于其他合成甜味剂具有口感纯正,安全性高,热量低等优点,因而自80年代以来一直风靡欧美市场,全球销量逐年     

氢键型N-马来酰-L-丙氨酸/PVA旋光性聚合物的合成

以马来酸酐与手性丙氨酸(L-丙氨酸)为原料,通过两步法合成了N-马来酰-L-丙氨酸,再通过氢键作用将其与聚乙烯醇(PVA)复合制备了氢键型N-马来酰-L-丙氨酸/PVA旋光性聚合物。采用傅里叶变换红外光谱仪,熔点仪和旋光仪对中间产物和最终产物的结构及性能进行了表征和测试,讨论了反应过程中的影响因素。结果表明:合成N-马来酰-L-丙氨酸较佳的工艺条件为:第一步的氨解反应温度25~35℃,反应介质采用冰乙酸;第二步是自缩聚合,以三乙胺为催化剂,得到最终产物的产率为93%。     

N-琥珀酰壳聚糖/氧化硫酸软骨素水凝胶的制备

采用N-琥珀酰壳聚糖(NCS)与氧化硫酸软骨素(OCS)进行复合,制备NCS/OCS复合水凝胶.考察了OCS与NCS不同质量比对复合水凝胶的凝胶化时间、压缩强度、平衡溶胀以及体外降解等物理化学性能的影响.结果表明:当m(NCS):m(OCS)为7:3时复合水凝胶能满足临床要求,此时复合水凝胶在37 ℃条件下的凝胶时间约为16 min,压缩强度为(5.82±0.5) kPa,30d后,复合水凝胶的剩余质量分数约为40％.通过氧化硫酸软骨素与N-琥珀酰壳聚糖进行复合,可注射水凝胶的凝胶强度和降解性能得到明显改善,该材料有望在软骨组织工程支架方面得到应用.     

多孔半互穿温敏水凝胶点击反应固定化酶

以N-异丙基丙烯酰胺（NIPAM）为温敏单体,引入线性聚甲基丙烯酸-β-羟乙酯（PHEMA）或乙二胺胺化的聚甲基丙烯酸-β-羟乙酯（PAEMA）,制备多孔半互穿水凝胶,并引入马来酰亚胺基团修饰,制备了两种新型水凝胶酶固定化载体Ⅰ和Ⅱ,凝胶的平均孔洞大小均约在10 ?m以上。以Ⅰ和Ⅱ为载体,马来酰亚胺与巯基的点击反应为基础,进行脂肪酶与糖化酶的固定化研究。结果表明,通过点击反应固定化得到的固定化脂肪酶最高活力回收率达6.03%,是相同条件下戊二醛固定化的5倍左右,且稳定性较高。     

N-丙烯酰-L-苯丙氨酸的制备与表征

以丙烯酸和L-苯丙氨酸为原料,在丙酮水溶液中反应得到N-丙烯酰-L-苯丙氨酸。产物经熔点测定,红外、核磁表征。     

聚N-异丙基丙烯酰胺类凝胶及其温敏性和酸敏性的研究

以N-异丙基丙烯酰胺为基础制成四种凝胶:①N-异丙基丙烯酰胺均聚凝胶;②N-异丙基丙烯酰胺与甲基丙烯酰胺共聚凝胶;③N-异丙基丙烯酰胺与甲基丙烯酸钠共聚凝胶;④N-异丙基丙烯酰胺与丙烯酰胺共聚,经水解生成的凝胶。探讨了引发剂、促进剂和交联剂及单体总浓度对凝胶化时间或凝胶的溶胀性能的影响,以及凝胶的温敏与酸敏相变条件。设计了温敏凝胶萃取过程,并对牛血清蛋白、碱性蛋白酶以及某种人体激素溶液进行浓缩实验。结果表明其具有良好的实用前景。     

D-葡萄糖酸酰胺类凝胶因子结构对其凝胶触变性能影响的研究

以凝胶因子N-己基-2,4-（3,4-二氯苯亚甲基）-D-葡萄糖酸酰胺为基础,合成出了3种新的凝胶因子,并对4种凝胶因子的乙酸丁酯凝胶的流变学性能进行了测试,发现它们均具有触变性,而N-（3-丙氧基）丙基-2,4-（3,4-二氯苯亚甲基）-D-葡萄糖酸酰胺凝胶因子的乙酸丁酯凝胶可过度恢复,而其它3种凝胶仅能部分恢复。为了探讨其中原因,分别对4种凝胶进行了红外光谱测试和荧光光谱测试,发现侧链中的氧原子在凝胶恢复过程中参与到了氢键形成从而加强了分子间的氢键作用,从而使其凝胶的机械性能在恢复后有所增强。而π-π堆积恢复后的减少,导致了其他3种凝胶因子的乙酸丁酯凝胶不能完全恢复。     

马来酸依那普利的合成与表征

研究了由3-苯甲酰丙烯酸乙酯和L-丙氨酸苄酯对甲苯磺酸盐缩合并用Pd/C催化加氢还原合成N-[(S)-1-(乙氧羰基)-3-苯丙基]-L-丙氨酸,再用双(三氯甲基)碳酸酯进行酰氯化,最后与L-脯氨酸直接缩合成盐获得马来酸依那普利的新方法.产品总收率为50%.对产品结构进行了表征.     

琼脂糖凝胶的N-羟基丁二酰亚胺修饰及其性能鉴定

采用烯丙基缩水甘油醚对国产交联琼脂糖凝胶进行活化,与巯基乙酸反应后,偶联N-羟基丁二酰亚胺(NHS),得到连接臂长度为10个原子、具有对氨基高度特异性的琼脂糖凝胶活化中间体. 通过控制琼脂糖凝胶活化双键的量,可使NHS的修饰密度处在较宽范围(20~150 mmol/mL),有效减少介质上杂基团的引入并有利于配基密度的设计. 活化过程对介质的理化性能无明显影响,活化介质在30 min内即可完成对L-苯丙氨酸的偶联,效率在90%以上,且在多种溶液中贮藏30 d后配基稳定性良好,几乎无泄露.     

溶胶-凝胶法制备金属-炭凝胶材料的研究进展

溶胶-凝胶法制备炭材料是近年来材料研究中的热点之一。该方法通过在成胶过程中直接加入金属前驱体的缩聚-干燥-炭化过程来制备炭凝胶及金属-炭凝胶。本文评述了金属-炭材料制备、应用的研究进展,阐述了炭凝胶及金属-炭凝胶的合成机理,介绍了多种金属-炭凝胶的制备和应用情况,并对其未来的发展方向进行了展望。     

硅胶催化合成3,6-二溴咔唑

以咔唑、N-溴代丁二酰亚胺(NBS)为原料,硅胶为催化剂,合成3,6-二溴咔唑,考察了反应时间、原料配比、溶剂用量和催化剂用量对反应的影响。正交实验表明,较佳工艺条件为:咔唑、NBS的摩尔比为1∶2,二氯甲烷50 mL,硅胶17 g时,室温下反应12 h,收率达89.25%,熔点为213.5℃。产物结构经TLC、IR进行表征。     

Swelling behavior of submicron gel particles

We prepared submicron Poly(N-isopropylacrylamide) gel particles. Their swelling behavior was investigated by a photon correlation spectroscopy (PCS) technique. The swelling behavior of submicron gel particles showed a continuous volume phase transition for various temperatures. We combined the extended Flory-Huggins model for mixing solvent and network with a modified Flory-Rehner theory for the elastic contribution. The proposed model agreed very well with swelling behaviors of both submicron gel particles and bulk gels. A continuous volume phase transition behavior of submicron gel particles was predicted successfully by the proposed model. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 109–114, 1998     

Synthesis and swelling characteristics of responsive carboxybetaine gel

A polyimminium gel, Dimedone‐[N, N′ melaminium] butyrocarboxylate copolymer, comprising of zwitterionic carboxybetaine repeat units was synthesized via a catalyst free facile polycondensation approach. The polymer was studied for its photoluminescence, thermal, and swelling behavior. Swelling behavior was investigated in different solvent mixtures as well as in pure solvents. The extent of swelling was dictated by solvent composition, such as dielectric constant, pH, ionic strength, and other variables for instance, temperature and crosslinking density. Gel was soluble in alkali and could be regenerated on treatment with an acid. This pH responsive behavior could find various industrial applications, especially in wastewater treatment. A preliminary study on sorption of dyes was also carried out. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

凝胶网络中溶剂性质的分子动力学模拟

本文利用分子动力学(MD)方法模拟了三种不同结构的凝胶网络系统,对系统的压力、溶剂的自扩散系数以及溶剂在凝胶不同区域的密度分布等进行了考察。模拟结果表明,被吸收进入凝胶网络的溶剂的性质与纯溶剂的性质有很大的差别,但凝胶结构的不均匀性对凝胶网络中溶剂的性质几乎没有什么影响。     

EVA38/Tween20凝胶气体分离膜的制备及其性能

采用溶剂挥发法制备了EVA38/Tween20凝胶膜,研究了不同Tween20含量对凝胶膜物理化学结构和气体渗透性能的影响。结果表明,Tween20与EVA38具有良好的相容性。Tween20的引入降低了膜的结晶度和熔融温度,也明显改善了膜的柔顺性,因而膜的CO2和N2渗透系数显著增加。同时膜的CO2/N2选择性也增加,这可以归因于Tween20中的乙氧基团对CO2强的选择吸附作用。当Tween20添加量从0增加到100%（以EVA38质量为基准）时,凝胶膜的CO2渗透系数由EVA38膜的89.5 Barrer增加到285 Barrer,CO2/N2理想分离因子从14.92增加到19.13。     

Molecular weight distribution of phenol-formaldehyde resols by high performance gel permeation chromatography

Resol resins are particularly difficult to characterize with respect to molecular weight because of the large amounts of caustic soda (10–20% w/w) which they contain. A method is described for solubilizing these materials using trichloroacetic acid, such that molecular weight distribution can be measured using a normal gel permeation chromatography system with μ-Styragel columns and tetrahydrofuran as solvent.     

A method for bleaching rice bran oil with silica gel

The color of bleached rice bran oil can be improved by silica gel treatment of the oil miscella before or after dewaxing. A silica gel/oil/solvent ratio of 1:5:5 (wt/wt/vol) is suitable. Silica gel treatment can be carried out either by column percolation or by merely shaking the miscella with the gel followed by decantation. However, column percolation is more efficient, with 30–72% color reductionvs. 19–36% reduction for shaking and decanting.     

超高相对分子质量PA6冻胶体系的结构与性能

以三氯化镓(GaCl_3)、氯化锂(LiCl)、苯甲醇、氯化钙(CaCl_2)作为络合剂或溶剂,分别配制PA6/GaCl_3/硝基甲烷(CH_3NO_2)、PA6/LiCl/甲酸、PA6/苯甲醇和PA6/CaCl_2/甲酸等体系,制得冻胶试样,采用差示扫描量热法、红外光谱分析、X射线衍射和扫描电子显微镜等方法对冻胶试样的结构与性能进行了分析对比。结果表明:各个PA6冻胶体系的形成机理不同,各体系冻胶结构和性能差异较大。GaCl_3,LiCl,CaCl_2主要是通过破坏PA6的内部氢键,对其进行络合成冻胶,但三者的络合能力又有所区别。苯甲醇主要是通过溶剂效应而形成冻胶。     

Thermoreversible hydrogels. IV. Effect of some factors on the swelling behavior of N-tetrahydrofurfurylacrylamide

A thermoreversible hydrogel, poly(N-tetrahydrofurfurylacrylamide) [poly-(NTHFAAm) gel], was prepared from N-tetrahydrofurfurylacrylamide, which was synthesized from N-tetrahydrofurfurylamine and acryloyl chloride (through acylation), with N,N′-methylenebisacrylamide, a crosslinker, in various aqueous solutions. The influences of temperature, gel thickness, and polymerization media on the swelling behaviors in water were investigated. The effect of the gel thickness on the swelling ratio for NTHFAAm gel indicated that the equilibrium swelling time and diffusion coefficient for the thinner gel were faster than those for the thicker gels. The effects of different polymerization media on the gel swelling ratio showed that the larger the solvent molecular size and the poorer the miscibility of the monomer and solvent, the higher the swelling ratio and diffusion coefficient. The drug release profiles in the various gels were also investigated. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1597–1603, 1998     

Direct drawing of gel fibers enabled by twist‐gel spinning process

A new twist‐gel spinning process for ultrahigh molecular weight polyethylene fibers is demonstrated which significantly increases the extraction rate of nonvolatile spin solvent while simultaneously reducing the consumption of extraction solvent by more than 75%. Applying twist to the gel fiber enables it to be directly hot‐drawn, allowing conventional solvent extraction to proceed significantly faster. While solvent extraction effectiveness is largely enhanced, the new process does not show reduced fiber properties. The tensile strength, Young's modulus, surface morphology, and geometry are relatively unaffected when compared to fibers produced using the conventional gel‐spinning process. The new twist‐gel spinning process is expected to improve the processing efficiency of gel‐spun high‐strength fibers, promoting broad expansion of these high performance fibers into applications that were previously prohibitive due to extremely slow production. POLYM. ENG. SCI., 55:1389–1395, 2015. © 2015 Society of Plastics Engineers