新型甜味剂—氯代蔗糖衍生物的合成及甜度评价

综述了新型甜味剂－氯代蔗糖衍生物的合成方法及甜度评价。     

新型甜味剂─氯代蔗糖衍生物的合成及甜度评价

综述了新型甜味剂─氯代蔗糖衍生物的合成方法及甜度评价。     

三氯蔗糖制备中氯代工艺的研究

综述了制备三氯蔗糖路线中氯代工艺的进展,阐述了氯代试剂、反应温度、反应物的配比对氯代反应的影响.     

Vilsmeier氯代制备三氯蔗糖-6-乙酸酯反应机理及氯代废液治理方法的研究

本文根据Vilsmeier试剂氯代反应制备三氯蔗糖-6-乙酸酯的机理,揭示该氯代反应必须经过升温氯代和碱催化水解两步反应完成。并对氯代废液中的主要残余物质,包括DMF、二甲胺、氯盐、甲酸盐等回收处理进行了探讨。     

氯代硝基苯合成氯代苯胺的进展

氯代苯胺是一类重要的化工原料,广泛用于染料、香料、医药及橡胶助剂等行业。本文综述了氯代硝基苯还原制备氯代苯胺的几类方法,对各类方法进行了对比和讨论,其中环境友好的催化加氢还原法可通过添加脱氯抑制剂和改善催化剂性能两条途经来提高反应的选择性。认为催化加氢法是制备氯代苯胺的首选方法。     

氯代硝基苯催化加氢制备氯代苯胺的研究进展

综述了近年来氯代硝基苯催化加氢制备氯代苯胺的研究进展。对铂基、钯基、钌基和镍基非均相催化剂的结构和催化性能进行了比较,讨论了催化剂助剂抑制脱氯副反应的机理。铂基催化剂活性和选择性较高,但是铂金属价格昂贵,且不能完全避免脱氯副反应;钯基和镍基催化剂活性好,但脱氯严重,通常需要引入脱氯抑制剂或使其形成非晶态合金提高产物的选择性;钌基催化剂的活性比铂基、钯基、镍基催化剂低,但选择性高,如何提高钌基催化剂的催化活性是今后的研究方向。     

氯代苯甲酸的氰化

本文报道了氯代苯甲酸在脱水剂氨基磺酸等的存在下与尿素反应,进行直接氰化将羧基转变成氰基生成氯代苯腈的情况。并详细地研究了邻氯苯甲酸进行这种直接氰化的反应条件。当邻氯苯甲酸与尿素和氨基磺酸的摩尔比为1:1.5:1.5时,能直接地高产率地得到相应的芳腈,且纯度较好。本合成法无需专门的反应装置,操作简便,反应能很快地顺利进行,同时没有严重的污染、三废问题也较易解决。本合成法特别适合中小化工企业,是合成取代芳腈的一个新途径。     

氯代苯酐的合成

介绍由邻二甲苯氯代,再经空气氯化及异构体分离合成氯代苯酐中试规模的合成路线。氯化中采用现行商品苯酐氧化的固定床催化剂催化氧化,并采用45块理论塔板的分离得到纯度大于98％的3－氯代苯酐和4－氯代苯酐。     

甜味剂三氯蔗糖的合成工艺与应用研究进展

本文综述了近年来国内外新型强力甜味剂三氯蔗糖的生产与应用概况,主要介绍了三氯蔗糖的合成工艺进展。     

值得大力开发的氯代烷烃系列产品

分析了氯代正丁烷、氯代叔丁烷、氯代异丁烷、氯代异丙烷、氯代仲丁烷等氯代烷烃的应用与市场前景。并对氯碱企业开发这些产品的可行性进行了讨论。     

蔗糖衍生物甜度与结构的关系综述

就如何提高蔗糖甜度、卤代蔗糖甜度与结构的关系、以及蔗糖结构与性能的计算机模拟等问题作了简单阐述.     

用分子结构特征分析法研究氨基酸甜味产生原因

采用全略微分重叠法（ＣＮＤＯ法）对１３种呈味氨基酸的分子结构特征进行了计算，并对其与甜味间的关系进行了相关分析，结果表明：氨基酸α－Ｈ、羰基－Ｏ以及氨基上的一个氢原子与甜度极显著相关（Ｐ〈０．０１）。氨基酸可能以氢供给基（α－Ｈ）和氢接受基（羰基－Ｏ），与甜味接受体上的氢接受基（Ｂ）、氢供给基（ＡＨ）结合形成氢键；氨基上的一个氢原子与甜味接受体上第三点结合形成氢键，其强度决定甜味的强弱。     

Influence of Structure on Saltiness and Sweetness of Dehydrated Food Products

Pore structure of foods influences the quality and texture of dehydrated food products. The development of food products with different pore structures and its effect on the sensory characteristics of the products were investigated. Potatoes and bananas were osmotically pre-treated using salt and sucrose solutions, respectively, and dehydrated with various drying methods, such as air drying, freeze drying, and vacuum drying, in order to obtain different pore structures. Simple mathematical models were developed in order to correlate the structural properties with process conditions. Depending on the drying method, porosity varied from 5% to 75% for potatoes and from 15% to 60% for bananas. Porosity was higher for the samples that were freeze-dried at lower pressures, followed by samples freeze-dried at higher pressures and, finally, vacuum- and air-dried samples. The surface areas of the dried samples varied between 0.961 and 3.040 m²/g, which are typical values for dehydrated foods. Freeze-dried potatoes and bananas were found to be saltier and sweeter (Score 6.5–7.8), respectively, than air- and vacuum-dried products (Score 4.8–5.8). Bananas and potatoes with the highest porosity and the highest specific surface areas presented more intense taste, providing the opportunity of reducing the levels of salt and sugar of the produced products without affecting the salty or sweet taste.     

The Crystal and Molecular Structure of Dianhydrogossypol

Dianhydrogossypol (4,4′-dihydroxy-5,5′-diisopropyl-7,7′-dimethyl-bis(3H-naphtho[1,8-bc]furan-3-one)) was made by refluxing gossypol in m-xylene. Proton NMR spectroscopy was used to confirm that complete conversion was achieved over a time period of several hours. Single crystals of the compound were obtained by slow evaporation from dichloromethane. Diffraction studies indicate that this crystal form is tetragonal with a I4₁/a space group and with cell dimensions of a = b = 33.8265(4) Å, c = 9.1497(2) Å, V = 10469.4(3) Å³ at 100 K. The structure was solved by direct methods and was refined to an R1 value of 0.0415 on 6,408 independent reflections. Dianhydrogossypol exists as a pair of enantiomers within this structure. The two fused planar ring systems are oriented at a 117° angle to each other (i.e., close to perpendicular), and the isopropyl groups are oriented with the ternary carbon hydrogen atoms pointed inward toward the center of the molecule. Repeating groups of four molecules (of the same chirality) pack to form a helical structure that is supported by intermolecular hydrogen bonds. Each helix is surrounded by four neighboring helices that are composed of molecules of the opposite chirality. The helices form the walls of empty channels that are 5–6 Å wide. As has been found for some gossypol crystal forms, the open-channel structure of dianhydrogossypol might be useful for scavenging or carrying small molecules. Additional NMR studies confirm that dianhydrogossypol can be converted directly to gossypol lactol ethers in the presence of anhydrous alcohols.     

预约你的甜蜜

牛郎织女的故事告我们:一切美好都需要等待。在Cocoa Choice(可可巧兹)巧克力工坊上演的一幕幕甜蜜大戏,恰好演绎了这句话的真谛。     

The Crystal and Molecular Structure of Kinamycin C p-Bromobenzoate

The molecular structure of kinamycin C has been determined by means of an X-ray study of its p-bromobenzoate derivative, C₃₁H₂₃N₂O₁₁Br. The crystals are monoclinic, P2₁, with four molecules of the derivative and four molecules of benzene in a unit cell of dimensions: a = 18.404 ± 0.005, b = 21.299 ± 0.004, c = 9.049 ± 0.001 Å, and β = 90.07 ± 0.03°. Reflection intensities were measured visually from equi-inclination Weissenberg photographs taken with Cu Ka radiation. The structure was solved by the heavy-atom method, and was refined by the block-diagonal-matrix least-squares method using anisotropic temperature factors for all the atoms. The final R factor is 8.9%. The stereostructures of the two crystallographically independent molecules are almost identical. The skeleton of the molecule is made up of four fused rings: two of these form a 1,4-naphthoquinone system and the rest are a pyrrole and a cyclohexene ring. A cyano group is bonded to the nitrogen atom of the pyrrole ring, which is rather unusual in an antibiotic.     

漆酚的分子结构

本文扼要回顾了漆酚分子结构确定的进程。     

苦味酸碳酰肼的制备和分子结构的研究

论述了苦味酸碳酰肼的制备和分子结构测定的结果。采用了 X射线衍射、元素分析、红外光谱等对其进行了表征。晶体属于单斜晶系 ,P2 1/ c空间群 ,晶体学参数为 :a=1.184 0 (2 ) nm,b=1.30 96 (2 ) nm,c=0 .82 6 1(1) nm,β=10 9.2 1(1)°,V=1.2 0 96 (3) nm3 ,z=4 ,Dc=1.783g/ cm3 ,μ(Mo Kα) =16 0 m-1,F(0 0 0 ) =6 5 6。晶体结构经全矩阵最小二乘法修正 ,最终偏离因子 R=0 .0 4 5 7,WR=0 .12 4 3。     

对苯二胺类防老剂的色谱分析和分子构型

从胺类分子的立体结构中对映异构体之间的相互转化,使分子极性发生改变,来解释对苯二胺类防老剂在色谱分析时产生双头峰、前伸峰、拖尾峰等异常色谱峰的现象,以便于保证对该类产品纯度的正确分析,以协助生产和市场的正确发展。     

水溶性润滑添加剂的分子结构与性能

讨论了水溶性润滑添加剂的分子结构与性能的关系,认为添加剂的同一分子中包含亲水性,吸附性,疏水性和反应性基团,则可能兼有油性剂,抗磨剂和极压剂多种作用。