Synthesis and Properties of Imidazole-Blocked Toluene Diisocyanates

Abstract

Imidazole-, 2-methyl imidazole-, and benzimidazole-blocked toluene diisocyanates (TDI) were prepared and characterized by elemental analysis, IR, and NMR spectroscopy. Simultaneous TGA/DTA results showed that the thermal stability of the adduct decreases in the following order: imidazole-TDI > 2-methylimidazole-TDI > benzimidazole-TDI. Gelation test involving imidazole-blocked adducts and hydroxyl-terminated polybutadiene were also carried out. The cure rate of the adduct increases from the imidazole- to the 2-methylimidazole- and to the benzimidazole-blocked adduct. It is also found that the benzimidazole-blocked adduct shows better solubility in the polyols.     

Synthesis and antitussive activity of obtucarbamate A derivatives

Abstract

Obtucarbamate A was purified from Disporum cantoniense with good antitussive property. In present work, a series of obtucarbamate A derivatives were designed and synthesized from obtucarbamate A by microwave method, and their antitussive activity were evaluated. The results showed that the toluene diisocyanate was obtained with a yield of 95.1% using a simple method, 1-methyl-2-pyrrolidinone as solvent, temperature of 190?°C, microwave irradiation at 60?W power for 30?min. All compounds have good antitussive activity, and small steric hindrance unsaturated groups of ester chains and amino groups favor activity. It is the first reported of obtucarbamate A derivatives used as antitussive, and the results provide a basis for the application of obtucarbamate derivatives as new antitussive.     

异佛尔酮二异氰酸酯自聚产物的~(13)C-NMR研究

研究了用季铵盐N,N,N-三甲基-N-(2-羟基乙基)-氢氧化铵为催化剂时异佛尔酮二异氰酸酯(IPDI)自聚产物的合成,用13C-NMR1、H-NMR、不失真地极化转移增强(DEPT)1、3C-1H异核远程相关(HMBC)实验表征了产物结构.结果表明,自聚产物是三聚异氰酸酯,主要含有三聚体异氰脲基、异氰酸根.一维核磁谱及二维化学位移相关谱分辨出两种羰基,确定了氮上4种不同取代结构的分子链连接情况.对自聚产物的碳谱图进行了全归属.     

Study of the reaction between 1,5-naphtalene diisocyanate and polycaprolactone in different solvents

The reaction between polycaprolactone and 1,5-naphtalene diisocyanate has been investigated in solvents with different dielectric constants and hydrogen bonding powers (toluene, ethyl acetate, ethyl methyl ketone), and in the same solvents with the addition of a catalytic amount of dimethyl sulfoxide (DMSO). The reaction was considered to proceed over two steps, the reaction of the first NCO group being faster. The course of the reaction was measured by titration of the unreacted NCO groups, ¹H- and ¹³C-NMR spectroscopy, and size exclusion chromatography. By titration only the overall reaction order and reaction rate constants could be determined. DMSO accelerated the reaction in all three solvents, which was explained by the stabilization of the activation complex by DMSO. Both steps of the reaction could be specified by NMR spectroscopy. The ratio between the reaction rate constants for the first and the second step decreased with the increased hydrogen bonding strength of the solvent and with DMSO. By SEC only the reaction of the first NCO group could be determined due to the low resolution for higher molar mass reaction products with a broad distribution. The values obtained for the first step reaction rate constants were in good agreement with NMR values. © 1995 John Wiley & Sons, Inc.     

Studies on the effect of extraction of isophorone diisocyanate-based segmented polyurethanes

Linear segmented polyurethane was synthesised, using isophorone diisocyanate (IPDI), poly(tetramethylene oxide) glycol (PTMG) and 1,4 butanediol, for use in biomedical applications. The chemical stability of this polyurethane in hot methanol during Soxhlet extraction was studied by viscosity measurements, thermal studies, mechanical tests, ultraviolet and infrared spectral studies, and gel permeation chromatography. Hot methanol degrades the polymer at the allophanate linkages, while extracting low molecular weight polyurethane fractions. More urea linkages are formed in the extracted polymer.     

Determination of toluene diisocyanate in synthetic-rubber track by ion chromatography with ultraviolet detection after alkaline suppressor

In the present work,a novel analytical method was proposed for the determination of toluene diisocyanate(TDI)in synthetic- rubber track by ion chromatography(IC)coupled with an ultraviolet detector setting at 212 nm.TDI can be hydrolyzed to toluene diamine(TDA)which can be separated by cation-exchange IC easily.The optimum IC separation was performed on an IonPac CS12A column(150 mm×4.0 mm)using 20 mmol L~(-1)sodium sulfate,10 mmol L~(-1)sulfuric acid and 10%acetonitrile as eluent. It was found that a hi...     

1,5-萘二异氰酸酯与1,4-丁二醇基为基质的多嵌段聚氨酯弹性体的合成与性能

利用 1 ,5_萘二异氰酸酯 (NDI)和 1 ,4_丁二醇 (BDO)为均匀硬质分子单体 ,与不同软质分子单体 (聚醚、聚酯、聚硅氧烷 )缩合制备多嵌段聚氨酯弹性体 ,详细研究了硬嵌段相 (NDI)弹性体的结构与性能间的关系 ,发现随着硬嵌段相长度的增加 ,或者氨基甲酸酯中胺基与聚醚、聚酯、聚硅氧烷中软段氧原子间氢键的减弱 ,都导致微相分离程度的增加 ,造成聚合物熔点和熔化热的升高。硬嵌段相熔化的多峰行为是由于形成了NDI/BDO半微晶区 ,在退火时转变为更加有序的结晶微区 ,当温度高于 1 80℃时 ,由于氢键的断裂 ,NDI/BDO硬嵌段发生分解反应 ,该过程源于不很有序的硬嵌段半结晶微区。当温度高于 2 5 0℃时 ,发生快速的分解。在动态力学行为方面 ,NDI基聚醚弹性体比其它硅氧烷基的弹性体展示了更高的硬嵌段区的稳定性 ,同时 ,在使用温度范围内 ,也显示出最高的储能模量值 ,表明刚性对温度的依赖性 ,以及NDI/BDO硬嵌段中活性填料的显著影响     

Preparation and Properties of Polyurethane Hydrogels Based on Hexamethylene Diisocyanate/Polycaprolactone-Polyethylene Glycol

Hydrogels are considered an optimum material for controlled release drug systems and tissue engineering scaffolds since they are tri-dimensional networks. In this work hexamethylene diisocyanate (HMDI), polycaprolactone (PCL) and polyethylene glycol (PEG) were used to prepare polyurethane prepolymers using diethylene glycol (DEG) as a chain-extender. Then the prepolymer was used to fabricate the HMDI/PCL-PEG/DEG polyurethane hydrogels by free radical polymerization using benzoyl peroxide (BPO) as a cross-linking agent. The influences of the ratio of polyol on the contact angle, swelling ratio, morphology and cytotoxicity in-vitro of the HMDI/PCL-PEG/DEG polyurethane hydrogel were investigated. The biological behavior of the polyurethane hydrogels was analyzed by studying the cell behavior using the standard biological MTT (3–4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide) test. The Fourier transform infrared (FTIR) spectra results showed that the polyurethane hydrogels were successfully synthesized. The change of the molar the ratio of the polyhydric alcohols (PEG and PCL) played important roles in the swelling degree, the contact angle and the pore size. The HMDI/PCL-PEG/DEG polyurethane hydrogel (PCL/PEG = 1:3) was hydrophilic with many more large pores while the polyurethane hydrogel with PCL/PEG = 3:1 had a dense structure. The fibroblastic cell proliferation improved with decreasing relative PEG content; however, there were insignificant differences (P > 0.05) on all days of observation of the samples with various PEG contents compared with the negative control group. The MTT assays revealed that the cells were able to grow and proliferate quite quickly in the extracts of the HMDI/PCL-PEG/DEG polyurethane hydrogels as well as the extract of the negative control.     

Solvent and support effects in enantioselective hydrogenation of isophorone with (s)-α,α - diphenyl-2-pyrrolidinemethanol modified palladium

Asymmetric heterogeneous catalytic hydrogenation of isophorone has been investigated over (S)-α,α-diphenyl-2-pyrrolidinemethanol modified Pd. The influence of solvent and support effects is discussed. The impact of water, acidic and basic additives on enantioselectivity is described. This revised version was published online in June 2006 with corrections to the Cover Date.     

耐高温,耐腐蚀乙烯基酯树脂的研究

本文就乙烯基酯树脂进行了一些探讨,旨在提高其耐热、耐腐蚀性能,并着重研究了用异氰酸酯改性的乙烯基酯树脂。通过玻璃化转变温度、红外分析、静态试验样浸泡、透光率、介电损耗的变化,以及对其力学性能进行了考察。试验结果表明用甲苯二异氰酸酯对乙烯基酯树脂进行改性是有效的。