没食子酸制备三乙酰基没食子酰氯工艺研究

以没食子酸与乙酸酐合成三乙酰没食子酸(TAGA),进而以N,N-二甲基甲酰胺(DMF)为催化剂,与SOCl2酰氯化反应合成三乙酰没食子酰氯(TAGC),考察了溶剂、反应物配比、催化剂加入量、浴温及反应时间对产率的影响。结果表明,二氯甲烷反应效果最好,优化工艺条件为:TAGA与SOCl2摩尔比为1∶3,催化剂加入量1.2%,浴温60℃,反应时间3 h。在此条件下,TAGC产率可达92.9%。     

没食子酰微晶纤维素酯的制备及稳定性研究

阐述了没食子酰微晶纤维素酯抗氧化剂的制备方法。采用醋酐作为没食子酸的乙酰化试剂,用SOCl2作为酰氯化试剂,制得三乙酰基没食子酰氯;在催化剂的作用下,与微晶纤维素进行酯化反应,制得三乙酰基没食子酰纤维素。最后除去乙酰基即得没食子酰微晶纤维素酯。产物有清除烷基自由基、羟基自由基及超氧阴离子自由基的能力,其DPPH·清除率达到80％以上。分别考察了高温、紫外线照射及不同pH值等因素对DPPH·清除率的影响。结果表明,产物在40℃以下、pH为3．0-9．0时DPPH·的清除率比较稳定,且紫外线照射对产物的DPPH·清除率影响不大。     

对甲基苯磺酸催化合成三乙酰没食子酸

以没食子酸与乙酸酐为原料,对甲基苯磺酸作催化剂,合成三乙酰没食子酸,考察了原料配比、催化剂用量、反应时间、反应温度对产品的影响。结果表明,酰化反应较佳的工艺条件是：n（没食子酸）∶n（乙酸酐）∶n（对甲基苯磺酸）=1∶2∶0.5,反应时间为1.5 h,反应温度为60℃,此时三乙酰没食子酸的收率为77.58%。     

利用寡聚环糊精配基键合介质分离表没食子儿茶素没食子酸酯的新方法

研究了利用寡聚环糊精配基键合的高效凝胶介质分离纯化茶多酚中的表没食子儿茶素没食子酸酯的新方法。考察了不同种类的流动相对分离效果的影响。最终确定采用水／乙醇／乙腈为57／30／13（体积比）进行等梯度洗脱,一次色谱分离的收率和纯度分别为73％、98％,介质经过0．5mol／L的NaOH-水-30％乙酸简单再生后即可重复利用。     

酯化型表没食子儿茶素没食子酸酯对乳腺癌细胞凋亡的影响

目的探讨酯化型表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)对人乳腺癌细胞株MCF-7(Myc依赖性)和MDA-MB-231(Myc非依赖性)凋亡的影响。方法采用脂肪酶催化法对EGCG进行酯化修饰,2次硅胶柱层析纯化后,通过高效液相色谱-质谱(HPLC-MS)进行鉴定,并分析纯化的酯化型EGCG的稳定性。流式细胞术检测纯化的酯化型EGCG对MCF-7和MDA-MB-231细胞凋亡的影响。结果经酶法修饰并纯化后获得了EGCG单棕榈酸酯(EGCG-C16),HPLC中不同保留时间的酯化产物的相对分子质量一致,均为696;EGCG在普通培养基里产生的H2O2量远高于其在酸性培养基里及EGCG-C16在普通培养基里产生的H2O2量(P0.000 1),表明EGCG-C16的稳定性较EGCG好;EGCG-C16对MCF-7细胞具有明确的促进凋亡效应,而对MDA-MB-231细胞则无此效应。结论酯化型EGCG对Myc依赖性乳腺癌细胞具有特异性的促进凋亡效应,为进一步深入研究EGCG的抗肿瘤效应奠定了基础。     

铁催化酰氯化反应制备对苯二甲酰氯

研究了金属催化剂对氯化亚砜与对苯二甲酸发生酰氯化反应制备标题化合物的催化效果,发现铝和锌不能催化该反应,铁、硫酸铁、氯化铁对该反应具有一定催化效果,其收率可达80%左右;乙酰丙酮铁配合物与金属铁的催化效果基本相当;以柠檬酸铁配合物为催化剂,产物收率可达89%。产物通过气相色谱-质谱联用进行定性分析,并通过核磁共振波谱进行确认。气相色谱分析结果表明产物纯度高于99%。     

二乙酰乙二胺合成工艺研究

以乙二胺和乙酸为原料制备二乙酰乙二胺,综合考虑了催化剂、物料配比、反应时间和反应温度等因素对反应收率、产品品质的影响。优化了二乙酰乙二胺的合成工艺,不仅提高了产品收率,而且大大降低了产品中副产物的生成,有利于下游产品低温漂白活化剂四乙酰乙二胺的合成。     

从没食子酸结晶母液中回收没食子酸的萃取工艺

引言没食子酸又名五倍子酸,是一种应用很广泛的化工原料[1],可用作食品抗氧化剂、着色剂、净化剂、防腐剂等[2],且具有抗肿瘤、抗炎、抗突变等多种生物学作用[3]。没食子酸是单宁酸的水解产物,国内厂家大多数以含水解单宁的植物五倍子、塔拉为原料生产没     

二葡糖基没食子酸的合成及其性能研究

以没食子酸甲酯和五乙酰基葡萄糖为原料,经过乙酰化反应、成盐、酸化等过程合成了美白剂二葡糖基没食子酸,并通过IR,MS,¹H NMR和¹³C NMR确认了最终产物的结构。同时考察了美白剂二葡糖基没食子酸对酪氨酸酶活性的影响、酪氨酸二酚酶的抑制作用机制以及抗氧化能力。研究表明:以L-酪氨酸为底物时,二葡糖基没食子酸对酪氨酸单酚酶的半抑制浓度IC₅₀为1.46 mg/mL,以L-多巴为底物时,二葡糖基没食子酸对酪氨酸二酚酶的半抑制浓度IC₅₀为2.68 mg/mL,而且从Lineweaver-Burk图获得的抑制机理表明二葡糖基没食子酸对酪氨酸二酚酶的抑制作用表现为竞争性抑制,抑制常数K_m为2.43 mg/mL。没食子酸相比于同质量浓度下的V_max对DPPH自由基的清除效果更好,而二葡糖基没食子酸相比于同质量浓度下的V_c,其对DPPH自由基仍存在一定的清除作用。     

Development of gallic acid sensors based on polyimide-modified platinum electrode

A series aromatic polyimide (PI) membranes in the form of permselective films was synthesised from different dianhydrides with two diamine monomers for gallic acid (GA) measurement. The obtained PI films were examined by Spectroscopic techniques, Scanning Electron Microscopy (SEM) and thermal analysis techniques and then used to fabricate the selective films on the modified electrode. Because of their excellent film properties, as the permselective polymeric membranes were used for determination of GA in the presence of various interferences and real sample. The PI-1-modified Pt electrode showed a very high R-value (0.9935) and reproducibility for GA determination, as well as high selectivity.     

Reversible adhesive based on gallic acid modified acrylate

An inexpensive adhesive bearing polyphenol groups was synthesized in this work. In order to obtain the desired adhesive, gallic acid (3,4,5-trihydroxybenzoic acid) was chosen as the functional compound to modify hydroxyl acrylate copolymer. The rheology and creep properties of the adhesive expressed that its cohesive strength and fatigue resistance were both increased. The resultant adhesive presented a better bonding strength to different substrates, such as steel, polypropylene (PP) and polytetrafluoroethylene (PTFE). In addition, reversible adhesion could be stimulated by modulating the temperature. Shear strength for PP was not less than 0.5 MPa, furthermore that for steel was no less than 4 MPa and the maximum achieved 6 MPa.     

Photocatalytic ozonation of gallic acid in water

Aqueous solutions of gallic acid have been treated with five different oxidation‐radiation processes: visible and ultraviolet A radiation (VUVA), TiO₂ adsorption, ozonation, VUVA/TiO₂ photocatalysis and VUVA/O₃/TiO₂ photocatalytic ozonation. With the exception of VUVA radiation and TiO₂ adsorption, ozone and photolytic processes allow for the total removal of gallic acid in a period between 50 and 90 min. The time taken to achieve 100% gallic acid conversion depends on the oxidation process applied, photocatalytic ozonation being the most effective technique. Throughout the process, oxalic and formic acids were identified as byproducts. Some other unidentified compounds probably related to pyruvic, malonic and maleic acids were also detected. The appearance of these compounds can be justified from direct reactions of both hydroxyl radical and ozone in water. Only photocatalytic ozonation leads to total mineralisation of the organic matter in less than 90 min. The photocatalyst used, TiO₂, showed good activity and stability (no leaching was observed) after five consecutive photocatalytic ozonation runs with the same semiconductor‐catalyst mass. Copyright © 2006 Society of Chemical Industry     

Chitosan conjugated with deoxycholic acid and gallic acid: A novel biopolymer-based additive antioxidant for polyethylene

Chitosan, as a novel bioadditive antioxidant for commodity polymer, is proposed. Chitosan is successfully conjugated with deoxycholic acid and gallic acid (chitosan-DC-GA) via a simple reaction using the 1-ethyl-3-(3′-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide conjugating agent at room temperature in a heterogeneous system. Chitosan-DC-GA shows a deoxycholic acid (DC) and gallic acid (GA) content of about 40% each. Chitosan-DC-GA exhibits DPPH radical scavenging ability with EC₅₀ 1 mg mL⁻¹ based on the EPR technique evaluation. A model case study of chitosan-DC-GA with low-density polyethylene (LDPE) confirms improvement in compatibility, as seen from the sheet clarity, as well as the good dispersion of chitosan-DC-GA in LDPE matrices, as observed by scanning electron microscope. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

响应面法优化马桑皮没食子酸的酶法提取技术

采用单宁酶法从马桑皮中提取没食子酸,以单因素-响应面实验优化了提取工艺,对得到的没食子酸进行了纯化和结构鉴定,考察了纯化后没食子酸的抗氧化活性,并与传统的酸提取法相对比。实验结果表明,在以马桑皮原料用量为基准,单宁酶的添加量为20 u/g、体系pH 5、提取温度48 ℃、提取时间4 h的条件下,没食子酸提取率可达10.79%±0.65%。经NKA-9大孔树脂纯化后,酶法制备没食子酸的纯度为96.0%,高于酸提取法制备的没食子酸纯度81.3%,其结构经1HNMR、13CNMR及异核单量子关系（HSQC）进行表征。相比于酸提取法,酶法制备的没食子酸具有更强的抗氧化活性,在质量浓度为256 mg/L时,其对1,1-二苯基-2-三硝基苯肼（DPPH）自由基和羟基自由基清除率分别为78.81%和61.99%,对Fe3+还原能力值为0.685。     

响应曲面法优化木薯酒精污泥基活性炭制备及对没食子酸的吸附性能

以木薯酒精厂生产过程中产生的脱水污泥为原料,采用响应曲面法Box-Behnken模型优化了木薯酒精污泥基活性炭的制备工艺,同时对最优成品进行一系列表征分析,并将其应用于没食子酸废水的处理研究.活性炭的最优制备条件为活化温度489℃,浸渍时间14h,活化时间51 min,氯化锌浓度21.53％,该条件下样品的碘吸附值达5...