Carbohydrate content of potato (Solanum tuberosum L.) tubers treated with Isopropyl-N (3-chlorophenyl) carbamate under different storage conditions

Post harvest application of Isopropyl-N (3-chlorophenyl) carbamate considerably reduced the degradation of starch when potato tubers were stored in an evaporative cooling chamber. The starch degraded at a faster rate when tubers were kept under refrigerated and room storage conditions.     

New HPLC Method to Determine Ethyl Carbamate in Alcoholic Beverages Using Fluorescence Detection

ABSTRACT: A new methodology to the quantification of ethyl carbamate (EC) has been developed. This method allows the analysis by HPLC of ethyl carbamate in samples of wine, fortified wine, and wine brandy, by a pre-column derivatization with 9-xanthydrol, and fluorescence detection. This does not require previous sample extraction or concentration. The method presents an average recovery of 96% among samples studied, a detection limit of 4.2μg/L, and an average intermediate precision of 6.3%. The comparison of the results obtained for EC analysis on the same wine brandy samples by GC/MS and HPLC are statistically indistinguishable with 97.5% probability. The results of the analysis of 42 samples are presented.     

Synthesis and characterisation of N-toluyl methacrylatoethyl carbamates,homopolymers and copolymers with methyl methacrylate

The paper describes the synthesis of N-2/4-toluyl methacrylatoethyl carbamates using 2/4-toluyl isocyanate and 2-hydroxyethyl methacrylate. Homopolymerisation and copolymerisation of these novel monomers with methyl methacrylate was carried out using benzoyl peroxide as an initiator and tetrahydrofuran as solvent. Photopolymerisation of N-4-toluyl methacrylatoethyl carbamate could be carried out without the use of photosensitiser. Structural characterisation of copolymers was done using ¹H-NMR. Thermal stability of copolymers was evaluated in a nitrogen atmosphere by dynamic thermogravimetry.     

2-氯乙基氨基甲酸乙酯气相色谱分析

采用气相色谱法，柱填充物为3％OV-101涂渍在Chromosorb W AW DMCS080～250μm）上，柱温：190℃，气化室：230℃，检测室：230℃；内标物为联苯，用内标法对2-氯乙基氨基甲酸乙酯有效成分进行分离和检验。方法标准偏差≤0．31，变异系数〈0．32，平均回收率为99．86％。     

羰基化法合成氨基甲酸酯催化剂的研究进展

对氧化羰基化法、还原羰基化法及氧化还原羰基化法3种羰基化合成氨基甲酸酯方法中催化剂的研究进展进行了综述,其中着重讨论了各种配体及助剂对催化剂活性的影响。指出今后的研究应集中在寻找高效、价廉及可重复使用的催化体系或对高效的均相催化体系进行负载化以及研究多相催化体系的催化机理。     

尿素嵌入法制备纤维素氨基甲酸酯的研究

探讨了尿素嵌入法制备纤维素氨基甲酸酯(CC)的生产工艺。指出:选用聚合度为450~625、α-纤维素含量大于90/的纤维素浆粕,用14/~16/的氢氧化钠溶液,于40~50℃条件下活化处理30~40min后,与尿素以1∶2~3的比例混合,在137℃的二甲苯体系中反应2~3h,便可得到含氮量为2.4/~3.5/的纤维素氨基甲酸酯产物。该产物在氢氧化钠溶液中可形成良好的稳定溶液,过滤性好,可直接用于纺丝。     

苯氨基甲酸酯催化合成研究进展

综述了国内外苯氨基甲酸酯合成方法和催化剂的研究进展,重点阐述了近年来以苯胺和碳酸二甲酯(DMC)为原料,合成苯氨基甲酸甲酯(MPC)催化剂的研究进展.同时对今后催化合成路线的研究和发展进行了讨论和分析,由苯胺和DMC合成MPC,副产物甲醇回收合成DMC,是零排放绿色工艺,其研究方向是开发出活性和选择性高的负载型催化剂.     

新闻纸的气相聚氨酯化处理及其机理的研究

用傅里叶变换红外光谱研究了气态甲苯-2,4-二异氰酸酯（2,4-Toluene Diisocyanate;TDI）与新闻纸的接枝共聚反应机理,并分析了经过聚氨酯化处理后的新闻纸的物理特性．结果表明：气态TDI与新闻纸纤维中的纤维素和半纤维素能够反应生成氨基甲酸酯结构,而与未漂浆中的酶解木素几乎不发生反应;新闻纸经过聚氨酯化处理后,在纸张表面纤维之间能够生成氨基甲酸酯结构,增强纤维之间的连接,对新闻纸的湿抗张强度和印刷表面强度有明显改善,但是干抗张强度、撕裂度和耐破度没有明显提高．     

纤维素氨基甲酸酯膜的制备及性能

采用碱/尿素/水体系对实验室自制的纤维素氨基甲酸酯(N%-1.8)在双螺杆中进行低温溶解,过滤、脱泡,得到清亮的纤维素氨基甲酸酯溶液。探讨制膜液浓度、凝固浴浓度、凝固浴温度,凝固时间对再生膜力学性能的影响,并结合FT-IR、XRD、SEM对膜的结构和形貌进行表征。结果表明,制膜液浓度为4.5wt%,凝固浴为H2SO4-8%、HOAc-16%和H2SO4/Na2SO4-7%/9%,凝固温度20~30℃,凝固时间为5min时所得的膜具有较好的力学性能,抗拉强度达到60~70MPa,断裂伸长率为6~10%。     

Characteristics of CO2 Absorption into Aqueous Ammonia

Abstract

Aqueous ammonia was investigated as a new absorbent of the chemical absorption process for CO₂ capture from combustion flue gas. The effects of the temperature and concentration of aqueous ammonia on CO₂ absorption in a semi‐batch reactor were studied by interpreting breakthrough curves. Raman spectroscopy analysis of CO₂ loaded aqueous ammonia provided concentration changes of bicarbonate, carbonate, and carbamate as well as CO₂ sorption capacity at given time during the absorption with 13 wt% aqueous ammonia at 25°C. It was observed that carbamate formation was dominating at the early stage of absorption. Then, the bicarbonate formation took over the domination at the later stage while the carbonate remained unchanged.