活性酯固化邻甲酚环氧树脂反应机理的研究

采用交叉反应研究在促进剂2-甲基咪唑存在下活性酯固化邻甲酚环氧树脂的反 应机理，用傅立叶转换红外（FTIR）原位测量技术，NMR，气-质联用（GC-MS）等 手段研究了模型化合物的反应动力学，并提出了其反应机理。结果表明，在促进剂 2-甲基咪唑存在下活性酯固化邻甲酚环氧树脂的反应是通过分子内机理进行的。     

Mesogenic properties and the effect of 1,2,4-trisubstitution on the central benzene nucleus of a three-ring mesogen

Four mesogenic homologous series have been synthesized by fixing a rigid 4-substituted phenylazo group to a resorcinol moiety. In series I and II, one phenolic -OH group is esterified by 4-n-alkoxybenzoyl groups; in series III and IV both the phenolic -OH groups are esterified by 4-n-alkoxybenzoyl groups. All the homologues of series III and IV exhibit low melting smectic C phases. Monoesters of series I and II, having free lateral hydroxy group with strong hydrogen bonding, exhibit high temperature nematic phases. The effect of different substituents on mesomorphic properties is discussed. One homologue of series III was doped with a chiral dopant and its spontaneous polarization evaluated.     

Determination of the Esterification Degree of Polygalacturonic Acid

The number of free and esterified carboxy groups of polygalacturonic acid was determined by conductometric titration.     

Mesogenic properties and the effect of 1,2,4-trisubstitution on the central benzene nucleus of a three-ring mesogen

Four mesogenic homologous series have been synthesized by fixing a rigid 4-substituted phenylazo group to a resorcinol moiety. In series I and II, one phenolic -OH group is esterified by 4-n-alkoxybenzoyl groups; in series III and IV both the phenolic -OH groups are esterified by 4-n-alkoxybenzoyl groups. All the homologues of series III and IV exhibit low melting smectic C phases. Monoesters of series I and II, having free lateral hydroxy group with strong hydrogen bonding, exhibit high temperature nematic phases. The effect of different substituents on mesomorphic properties is discussed. One homologue of series III was doped with a chiral dopant and its spontaneous polarization evaluated.     

Lipids of the fruit of Ficus carica

By chromatographic methods, about 30 groups of various lipid compounds belonging to the classes of neutral lipids, glycolipids, and phospholipids have been identified from the fruit of the fig tree. The main groups are triacylglycerols, free and esterified sterols, mono- and digalactosyldiglycerides, ceramide oligosides, cerebrosides, esterified sterol glycosides, and phosphatidylglycerols. In the fatty acid composition, linoleic, linolenic, oleic, and palmitic acids predominated (>90%).A. V. Bogatskii Physicochemical Institute, Academy of Sciences of the Ukrainian SSR, Odessa. Lomonosov Technological Institute of the Food Industry, Odessa. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 423–427, July–August, 1986.     

明胶酯化及酞酰化对于沉降性能的影响

酞酰化明胶作为中、低感光乳剂的沉降剂已经得到了广泛的应用。这个沉降剂的优点是沉降pH范围较窄,沉降速度较快,有增感作用,复溶容剔。它的主要缺点就是不适用于氨法高感乳剂。究其原因,主要是由于PA改性明胶的等电点比较低。     

Effect of Alkyl and Alkoxy Substituents on Complexation Ability of Phosphorus-Containing Cationites toward Indium and Gallium Cations

Russian Journal of Physical Chemistry A - Effect the nature of substituents in free and esterified phosphonic and phosphinic-acid groups has on features of the sorption behavior of indium(III) and...     

Study of pepsin phosphorylation using immobilized metal affinity chromatography

The interactions of pepsin with immobilized trivalent metal ions and the participation of the enzyme phosphate group in this process were investigated using high performance immobilized metal affinity chromatography. Two different sorbents were used: the newly prepared one, consisting of Ga(3+ )chelate of (6-amino-1-hydroxyhexane-1,1-diyl) bis(phosphonic acid) covalently bound to a methacrylate support (BP-Ga(3+)), and the commercial one, containing immobilized Fe(3+ )ions (POROS MC20-Fe(3+)). The comparison of the behavior of porcine pepsin A and its partially dephosphorylated form on both sorbents showed that both forms of pepsin were adsorbed under the same conditions. To eliminate the participation of free carboxyl groups in pepsin adsorption, both enzyme forms were modified by amidation or esterification. Native enzyme and its partially dephosphorylated form both with modified carboxyl groups differed in their interaction with immobilized Ga(3+ )and Fe(3+). Phosphorylated pepsin molecules with esterified carboxyl groups were adsorbed on both sorbents while nonphosphorylated ones with esterified carboxyl groups were not adsorbed.     

Diacylated Triterpenoid Saponin from Silene szechuensis

TherootofSileneszechuensisisaChinesetTaditionalmedicinewhichcanbeusedtotreatgaStralgia'.Fromethanolicextractoftheplantanewdiacylatedtriterpenoidsaponin,silenosidel,wasisolated.Thestructureofthesaponinwaselucidatedafterderivatives2~10wereobtained.Sele...     

Total synthesis of tylonolide,the aglycone of the 16-membered ring macrolide tylosin,from D-glucose. Selective application of MPM and DMPM protecting groups for hydroxy functions

Segments i (C11–C17) and ii (C1–C10), synthesized from D-glucose by employing some stereoselective reactions and benzyl-type protecting groups, were esterified and cyclized to the 16-membered enone, which was readily converted to tylonolide, the aglycone of tylosin.     

基于超支化聚合物制备单分子纳米胶囊及对其包裹客体能力的研究

采用十六酰氯将商品超支化聚甘油醇部分酯化,再将残留的羟基转化为丙烯酸酯或甲基丙烯酸酯基,得到了两亲性超支化聚合物。通过1H NMR求得羟基的酯化度和所得两亲性超支化聚合物的数均分子量。此聚合物作为反相胶束型的单分子纳米胶囊,可用来包裹亲水性染料。用紫外光谱评价了纳米胶囊对染料的包裹能力。结果表明,与不含功能基的单分子纳米胶囊相比,带有少量丙烯酸酯基的纳米胶囊可以包裹更多的亲水性染料,且含丙烯酸酯基比含甲基丙烯酸酯基的纳米胶囊包裹效果更明显。     

Vernetzung von Phenolcarbonsäureestern von Polysacchariden durch oxydative phenolische Kupplung

Guaran, a watersoluble polysaccharide, was esterified with various phenolic acids. Solutions of these esters formed gels upon oxidation. In these gels the phenolic ester groups were crosslinked by oxidative phenolic coupling, the corresponding dimeric phenolic acids being liberated by saponification.     

Rhodium catalyzed reductive esterification reactions

Reductive esterification occurs when unsaturated acids are treated with hydrogen in alcohol using either rhodium trichloride or the dimer of chloro(1,5-hexadiene)rhodium(I) as the catalyst. Saturated acids containing appropriate functional groups are also esterified under the same conditions.     

8-氯腺苷衍生物的合成及生物活性研究

N^6－甲基－8－氯腺苷的合成是以N，N－二甲基乙酰胺为溶剂由腺苷与碘甲烷反应，生成N^1-甲基－8－氯腺苷，经过Dimorth重排而得到，优化反应条件后，N^1-甲基－8－氯腺苷收率为52％。8－氯腺苷糖环羟基被酯化后失去原有的生物活性，碱基环外氨基氢被甲基取代后基本保持原有的生物活性。     

吸水过程对环氧树脂的动态松弛行为的影响

以酚醛树脂和乙酸、正丁酸和苯乙酸酯化的酚醛树脂固化邻甲酚环氧树脂.应用称重法、示差扫描量热法(DSC)和动态机械分析法(DMA)等手段研究吸水过程对环氧树脂的动态松弛行为的影响.结果表明,吸水过程对酚醛树脂和酯化酚醛树脂固化体系的动态松驰行为有显著的影响,这是由于两种体系中侧基对吸水过程及与水分子的相互作用不同所致.     

汽车空调器压缩机用冷冻机油的研究

采用三氟化硼乙醚 (BF3·Et2 O)催化体系合成较高粘度的环氧丙烷均聚醚 ,观察了不同反应参数对聚醚粘度的影响。同时考察了不同催化剂对聚醚酯性能的影响。结果表明 ,用固体钨硅酸合成的聚醚酯较对甲苯磺酸的性能好     

Stereoselective glycosylation using the long-range effect of a [2-(4-phenylbenzyl)oxycarbonyl]benzoyl group

Highly α-selective glucosylation was effected by virtue of the solvent effect of cyclopentyl methyl ether and the long-range assistance of bulky 6-O-protective groups. Higher α-selectivity was obtained by the use of this solvent in comparison to conventional diethyl ether. α-Selectivity was further improved with the influence of 6-O-substituents, such as TBDPS and phthaloyl groups, the latter being mono esterified with a bulky alcohol.     

脂肪酸甲酯乙氧基化物的气相色谱分析

用0.5 mol/L KOH乙醇溶液水解脂肪酸甲酯乙氧基化物(FMEO),酯键断裂,其疏水基甲 酯化、亲水基硅醚化后分别用气相色谱法测定其组成,并采用峰面积归一化法进行了组分的 定量。成功测定了各种FMEO样品的疏水基组成和环氧乙烷(EO)加成数分布,方法简单,重复性 好,尤其是对原料为混碳脂肪酸甲酯的FMEO更有意义。     

Esterification of polymeric carboxylic acids

Polymers containing pendant carboxyl groups have been essentially completely esterified with little apparent change in molecular weight by the use of one of the following reagents: (1) trialkyl orthoesters, (2) dimethylformamide dialkyl acetals, (3) tertiary amines followed by alkyl halides, (4) quaternary ammonium hydroxide followed by alkyl halides. The use of some of these methods permits preparation of certain polymers that were previously not readily accessible.     

Mass spectra of porphyrin alkyl esters and their copper complexes. Studies on products from humans and animals with porphyria

Mass spectra of methyl and higher aliphatic esters of biologically important porphyrins—prepared from human and bovine excreta—were recorded. Variation in the number of esterified carboxyl groups (4 to 8) or in the size of the ester groups causes no change in the fragmentation modes; only the abundances of the fragment ions vary. The conversion of a porphyrin ester to its copper-complex (chelate) has been achieved in a simple way. The mass spectra of the copper chelates are compared with those of the free porphyrin esters and minor differences are observed.