Acylation of Benzene over Clay and Mesoporous Si-MCM-41 Supported InCl3, GaCl3 and ZnCl2 Catalysts

Liquid phase acylation of benzene by acyl chloride (e.g., benzoyl chloride, butyryl chloride or phenyl acetyl chloride) over InCl₃, GaCl₃ and ZnCl₂ supported on commercial clays (viz. montmorillonite-K10, montmorillonite-KSF and kaolin) or high silica mesoporous MCM-41 at 80°C has been investigated. The Mont.-K10 and Si-MCM-41 supported InCl₃ and GaCl₃ catalysts showed high activity in the acyation of benzene by benzoyl chloride even in the presence of moisture in the reaction mixture. The redox function of the supported InCl₃, GaCl₃ or ZnCl₂ catalysts seems to play a very important role in the acylation process.     

吐纳麝香的合成

研究了吐纳麝香的合成方法 ,提出了由伞花烃合成中间体 1 ,1 ,3 ,4,4,6六甲基四氢萘和 7乙酰基 1 ,1 ,3 ,4,4,6六甲基四氢萘的合成路线 ,优化了反应条件并讨论了反应机理。     

Acylation and Solubility of Casein Precipitated by Carbon Dioxide

Casein precipitated from milk using carbon dioxide (CO₂-casein) and calcium caseinate were acetylated and succinylated. Aqueous solubility of casein was measured at pH 3, 5, 7, and 9. Acetylation extent was lower for CO₂-casein while both succinylated to similar extents. Solubility between the unmodified caseins was similar except at pH 5 with CO₂-casein being less soluble. Succinylation enhanced solubility for both caseins at pH 5, 7, and 9 with similar solubility between the succinylated caseins at each pH. Acetylation enhanced solubility at pH 5, however CO₂-casein still possessed lower solubility than calcium caseinate. Acylation and solubility behavior indicated structural features in CO₂-casein which were not present in calcium caseinate.     

Acylated Anthocyanins from Red Cabbage and Purple Sweet Potato Can Bind Metal Ions and Produce Stable Blue Colors

Red cabbage (RC) and purple sweet potato (PSP) are naturally rich in acylated cyanidin glycosides that can bind metal ions and develop intramolecular π-stacking interactions between the cyanidin chromophore and the phenolic acyl residues. In this work, a large set of RC and PSP anthocyanins was investigated for its coloring properties in the presence of iron and aluminum ions. Although relatively modest, the structural differences between RC and PSP anthocyanins, i.e., the acylation site at the external glucose of the sophorosyl moiety (C2-OH for RC vs. C6-OH for PSP) and the presence of coordinating acyl groups (caffeoyl) in PSP anthocyanins only, made a large difference in the color expressed by their metal complexes. For instance, the Al³⁺-induced bathochromic shifts for RC anthocyanins reached ca. 50 nm at pH 6 and pH 7, vs. at best ca. 20 nm for PSP anthocyanins. With Fe²⁺ (quickly oxidized to Fe³⁺ in the complexes), the bathochromic shifts for RC anthocyanins were higher, i.e., up to ca. 90 nm at pH 7 and 110 nm at pH 5.7. A kinetic analysis at different metal/ligand molar ratios combined with an investigation by high-resolution mass spectrometry suggested the formation of metal–anthocyanin complexes of 1:1, 1:2, and 1:3 stoichiometries. Contrary to predictions based on steric hindrance, acylation by noncoordinating acyl residues favored metal binding and resulted in complexes having much higher molar absorption coefficients. Moreover, the competition between metal binding and water addition to the free ligands (leading to colorless forms) was less severe, although very dependent on the acylation site(s). Overall, anthocyanins from purple sweet potato, and even more from red cabbage, have a strong potential for development as food colorants expressing red to blue hues depending on pH and metal ion.     

C.I.酸性棕28的合成研究

本文介绍了C.I.酸性棕28的合成工艺.酰化反应使用焦亚硫酸钠作为稳定剂,反应温度控制在80℃左右,反应收率达到95%;用正丁醇作为偶合反应的溶剂,产物的收率明显提高;络合反应控制pH在8～8.5,反应时间短,产品收率高,色光艳.     

负载型铁催化剂的制备及其在2,4,6-三甲基苯甲酸合成中的应用

研究了负载型铁催化剂的制备方法以及催化剂制备条件对2,4,6-三甲基苯甲酸合成中间体α-氯代-2,4,6-三甲基苯乙酮产率的影响.结果表明,适宜的催化剂制备条件为:以Al2O3为载体,铁负载量20％,活化温度400℃.通过正交实验得到使用该催化剂的最适宜酰基化反应条件:均三甲苯和氯乙酰氯的摩尔比1∶2,反应时间4h,反...     

酶法制备葛根素的丙酯衍生物

本文研究了不同种类的水解酶催化非水相葛根素丙酰化反应的催化效率,并研究以Novozym 435脂肪酶催化葛根素丙酰化反应为模型,几个关键反应因素对该模型的影响规律。研究发现固定化脂肪酶Novozym 435、Lipozyme IMTL、Lipozyme IMRM均能高效催化葛根素丙酰化反应,且转化率高达98%以上,但另外几种游离脂肪酶催化葛根素丙酰化反应活性及效率就特别低。相同条件下,猪胰脂肪酶催化葛根素丙酰化反应的转化率为67%左右;胰脂肪酶和CRL脂肪酶表现很低的催化活性,肽酶和蛋白酶没有表现催化活性。以四氢呋喃为反应溶剂,2 mg/m L Novozym 435脂肪酶,底物:酰基供体之比为1:30,水分含量为0的反应条件下,反应6 h,底物转化率达到99.5%。反应产物经分离纯化后进行了结构鉴定,高效液相色谱、质谱、傅里叶红外光谱结果表明,非水相酶催化葛根素酰化反应主要生成单酯,所得产物酯为葛根素丙单酯,区域选择性达98%。     

酰化大米蛋白理化性质及胰蛋白酶酶解性质研究

对酰化大米蛋白的溶解度、表面电荷情况及二级结构等理化特性进行初步探讨,同时研究了酰化大米蛋白胰蛋白酶酶解特性。结果表明,大米蛋白等电点随着酰化程度的增大,越来越向酸性方向迁移,由原来的4.8分别迁移到4.4、3.8、3.3。酰化能够改善大米蛋白的溶解性,从0.4 mg/m L提高到了0.7 mg/m L(中性p H)。酰化能够明显增加蛋白质表面的净负电荷,酰化程度越大,净负电荷增加越多。酰化对大米蛋白的二级结构也有一定的影响,α-螺旋和无规卷曲含量基本不变,β-折叠含量下降,β-转角的含量上升。酰化可以提高大米蛋白胰蛋白酶酶解速率和消化率,相同底物浓度时动力学参数a随着酰化度的增大而增大。酶解物电泳表明,胰蛋白酶酶解120 min后,未改性大米蛋白酶解物在20 k Da、16.9 k Da和14 k Da处仍有清晰可见的条带,改性大米蛋白酶解物则这些条带几乎都完全消失。     

毛纱上浆用丁二酸酐酰化明胶浆料的制备及其性能

针对明胶在室温凝胶且在毛纱上浆时存在浆膜韧性差的问题,采用丁二酸酐(C4 H4 O3)对明胶进行酰化改性,合成了一种毛纱室温上浆用改性明胶蛋白(Gel-C4 H4 O3)浆料.借助红外光谱仪、X射线衍射仪、扫描电子显微镜及差示扫描量热仪对Gel-C4 H4 O3浆料结构及玻璃化转变温度进行测试表征,系统研究了酰化度与G...