【作者】 吕丽丽；

【导师】 吕秀阳；

【作者基本信息】 浙江大学 ， 化学工程与技术， 2009， 博士

【摘要】 没食子酸及以其为原料制备的没食子酸酯、多羟基二苯甲酮等多羟基化合物均为重要的化工原料,广泛应用于食品、医药、化工等领域。近年来,美国等发达国家开始使用高纯度没食子酸、没食子酸丙酯等化合物替代邻苯二酚来洗涤大规模集成电路板,从而克服了邻苯二酚在清洗过程中易损害电板的缺点。由于知识产权保护及国际竞争等原因,国外一直未见与电子级没食子酸制备工艺相关的文献报道。尽管国内有少数学者对电子级没食子酸的制备工艺进行了初步研究,但缺乏全面的研究和理论方面的探索。本文对电子没食子酸制备过程中的若干基础问题进行了研究,并对树脂吸附+结晶相结合的制备工艺进行了初步探索,以期能够为电子级没食子酸的制备提供理论依据和实验基础。主要内容概括如下:首先,本文建立了一种同时分析含单宁生物质(五倍子粉和塔拉粉)水解产物中没食子酸和焦性没食子酸的液相色谱新方法。而后,利用高压反应釜首次系统研究了413.15 K-463.15 K范围内高温液态水中五倍子单宁和塔拉单宁及其水解中间产物没食子酸的无催化分解反应动力学。实验结果表明,在没有任何催化剂的情况下,五倍子单宁和塔拉单宁能够顺利水解生成没食子酸,没食子酸可进一步脱羧生成焦性没食子酸,通过控制反应条件可以选择性地得到中间产物没食子酸。采用一级连续反应动力学模型对实验数据进行拟合,得到五倍子单宁和塔拉单宁水解反应的表观活化能。其次,本文采用平衡法首次测定了没食子酸、没食子酸甲酯、没食子酸丙酯、没食子酸辛酯、2,4-二羟基二苯甲酮、2,3,4-三羟基二苯甲酮、2,3,4,4′-四羟基二苯甲酮和2,2′,4,4′-四羟基二苯甲酮等多羟基化合物在水+乙醇混合溶剂中的溶解度。结果表明,溶解度随温度升高、溶剂中乙醇含量的增加而增加;一般情况下,溶解度亦随溶质分子极性的增加而增加。接着,本文利用pH电位滴定法测定了没食子酸与多种金属离子所形成配合物的稳定常数,其中Fe(Ⅱ)、Al(Ⅲ)、Ni(Ⅱ)及Pb(Ⅱ)等金属离子与没食子酸所形成配合物的稳定常数未见其他文献报道。实验结果表明,没食子酸对多种金属离子具有较强的配位作用,主要形成ML型配合物,配合物稳定常数顺序符合经典的Irving-Williams顺序:Ca(Ⅱ)＜Mg(Ⅱ)＜Mn(Ⅱ)＜Fe(Ⅱ)＜Ni(Ⅱ)＜Zn(Ⅱ)＜Cu(Ⅱ)＜Fe(Ⅲ)＜Pb(Ⅱ)＜Al(Ⅲ)。同时,还利用紫外-可见光谱法对没食子酸与Fe(Ⅱ)、Zn(Ⅱ)、Al(Ⅲ)、Mn(Ⅱ)及Pb(Ⅱ)等金属离子在水溶液中的配位现象进行了研究,并着重从动力学和热力学角度对没食子酸和亚铁离子的配位现象进行了探讨。结果表明,没食子酸对这些金属离子有较强的配位作用,其中,没食子酸与Fe(Ⅱ)主要形成ML的配合物,反应为二级反应,根据Arrhenius方程和Absolute-rate理论得到该反应的表观活化能以及自由能,并基于实验现象提出了较为合理的反应机理。最后,本文对树脂吸附+结晶相结合制备电子级没食子酸的工艺过程进行了初步研究。采用超纯水为溶剂结晶提纯工业没食子酸,能够有效提高没食子酸纯度,并降低其中金属离子的含量,三次结晶即可将没食子酸含量从96.05%提高至99.77%,且使铁、钙、钠和钾等金属离子含量均降至1ppm左右,但继续增加结晶次数对提高没食子酸纯度和降低金属离子含量无明显效果。实验所用三种电子级树脂对目标金属离子均有一定的去除效果,其中,ZGC-ER80的效果较佳。部分普通树脂也可以有效地降低没食子酸中目标金属离子中的一种或全部,尤以氨基羧酸螯合树脂XSC-800效果较佳。本课题研究结果能为电子级没食子酸的制备提供大量基础数据和理论依据。更多还原

【Abstract】 Gallic acid(GA,3,4,5-trihydroxybenzoic acid) and several polyhydroxy-compounds synthesized by it are industrially important chemicals widely used in many fields such as organic synthesis, pharmaceutical and food.Recently;ultrahigh-purity gallic acid and propyl gallate have been used in electronics industry for replacing catechol(1,2-dihydroxybenzene) to remove the photoresist,other polymeric material or residue from the substrate.With the development of economics and the enhancement of environmental protection consciousness,gallic acid will certainly replace 1,2-dihydroxybenzene used currently in China.Due to the international competition and the protection of intellectual property rights,literature about the preparation process of ultrahigh-purity gallic acid is quite scarce. Accordingly,systematical exploration and theoretical study are currently unavailable as well.In the present study,several fundamental problems related to the preparation of ultrahigh-purity gallic acid were investigated.In addition,the preparation process combining the resin absorption and crystallization has been studied particularly.The main contents are summarized as follows.Firstly,in the non-catalyzed hydrolysis of gallotannin and tara tannin in high temperature liquid water(HTLW),after establishing a new high-performance liquid chromatography(HPLC) method for the analysis of tannin hydrolysis products,the decomposition reaction kinetics of tannins and their intermediate gallic acid were systematically studied for the first time in the temperature range from 413.15 K to 463.15 K. It was found that gallotannin and tara tannin could be hydrolyzed easily without catalysts and the reaction was indicated to be a typical consecutive first-order one in which gallic acid formed as a main intermediate product and pyrogallol as the final product.Additionally, selective decomposition of tannin in HTLW was proved to be possible by adjusting reaction temperature and time.Based on the assumption of first order kinetics equation,the apparent activation energies were evaluated.Next,the solubilities of several polyhydroxy-compounds,including gallic acid,methyl gallate,propyl gallate,octyl gallate, 2,4-dihydroxybenzophenone,2,3,4-trihydroxybenzophenone, 2,3,4,4’-tetrahydroxybenzophenone and 2,2’,4,4’-tetrahydroxybenzophenone,in ethanol+water mixture were determined by a static analytical method in the temperature range from 273.15 K to 363.15 K.As shown in the results,the solubilities increase as the temperature and the concentration of ethanol in the mixture solvent increase.In addition,the solubilities increase with the increasing molecular polarity generally.The simplifiedλ-h equation and two empirical equations were proposed to correlate the experimental data with good agreement.Then,the complexation of gallic acid with several metal ions was studied by means of acid-base potentiometric titration.The stability constants between gallic acid and Fe(Ⅱ),Al(Ⅲ),Ni(Ⅱ) and Pb(Ⅱ) were determined for the first time.Results showed that gallic acid can form stable complexes with metal ions involved in this study,and the sequence of stability constants is:Ca(Ⅱ)＜Mg(Ⅱ)＜Mn(Ⅱ)＜Fe(Ⅱ)＜Ni(Ⅱ)＜Zn(Ⅱ)＜Cu(Ⅱ)＜Fe(Ⅲ)＜Pb(Ⅱ)＜Al(Ⅲ).Simultaneously,the complexation between gallic acid and several metal ions was investigated by using UV-vis spectroscopy.Also, theoretical and experimental study on the complexation reaction of gallic acid with ferrous ion was performed systematically.The results showed that gallic acid can form stable complexes with metal ions investigated in this study,which makes the red shift of gallic acid in the presence of metal ions.The stoichiometric composition of GA-Fe(Ⅱ) complex was 1:1 under the adopted experimental conditions.The complexation reaction of gallic acid with ferrous ion was found to be a second order reaction. According to the Arrhenius equation and the Absolute-rate theory,the activation energy and free energy of activation of the complexation reaction were calculated.To understand the kinetic results obtained,a three step reaction mechanism was proposed,which can satisfactorily explain the dependence of the rate constant on the temperature,ionic strength and permittivity of the reaction medium.Finally,the preparationprocess of ultrahigh-purity gallic acid combining resin absorbance and crystallization was investigated particularly.As shown in the results,crystallization with ultrahigh-purity water can not only improve the purity of gallic acid but also decrease the concentration of metal ions effectively.After three times of crystallization,the purity of gallic acid increased from 96.05% to 99.77%,while the concentration of calcium,iron,sodium and kalium ions were all reduced to around 1 ppm.Different resins have different effects on the removement of metal ions.The three ultra-cleaning resins with high purity all have good effects,especially ZGC-ER80.Treating with several resins with common purity,such as XSC-800 and 001×10,the concentration of metal ions in gallic acid can also be reduced effectively.The information yielded from this work will provide essential basic data and theoretical instruction for the preparation process of ultrahigh-purity gallic acid.更多还原