煤制乙二醇中间产物草酸二甲酯水解制草酸工艺研究

主要模拟生产流程对草酸二甲酯水解制备草酸进行研究,试验从5个关键因素着手,其中水解反应时间、水解温度、水酯比对水解转化率影响较大,增长反应时间、提高反应温度和增大水酯比均有利于提高草酸二甲酯转化率;搅拌速率对草酸二甲酯水解转化率影响不大,只要能满足传热要求即可;烘干过程即保证游离水蒸发,也尽可能避免草酸升华损失,选取1...     

NaOH冷冻-HCl再生预处理辅助碳基固体酸水解纤维素研究

本研究以提高纤维素转化率和还原糖得率为目标,以玉米秸秆制备的碳基固体酸为催化剂,采用Na OH冷冻-HCl再生为预处理方法,考察了预处理过程中Na OH浓度及纤维素水解过程中水解温度和水解时间对纤维素水解效果的影响。结果表明,在水解温度180℃、水解时间3h、纤维素0.15g、催化剂用量0.45g的条件下,纤维素水解还原糖得率38.78%,纤维素的转化率45.6%,与相同工艺条件下未经预处理的纤维素相比,还原糖得率及纤维素转化率分别提高了30.88%和31.1%,说明Na OH冷冻-HCl再生处理纤维素能够辅助提高碳基固体酸催化水解纤维素的效率。     

制备微粉用均相沉淀剂水解动力学

考察了碳酸二酰胺浓度、水解反应温度以及水解时间等参数对碳酸二酰胺水解反应转化率的影响情况 ,得到了不同浓度、不同水解温度、不同反应时间与其转化率的关系。实验结果表明 ,这些因素对碳酸二酰胺水解转化率都有不同程度的影响 ,但水解反应温度对碳酸二酰胺的水解速率的影响最为突出。同时各影响因素的确立为制备粒径可控的纳米级微粉提供了依据     

反应精馏水解醋酸甲酯中试实验

对反应精馏水解醋酸甲酯过程的研究，在小试的基础上进行了工业性规模试验。试验表明用反应精馏水解醋酸甲酯是可行的，单程水解转化率达到80％。由此设计了聚乙烯醇生产中溶剂回收工段的新工艺过程，该工艺过程醋酸甲酯分解率高、液体循环量小、蒸汽消耗低、循环水用量小。     

制备微粉用均相沉淀剂水解动力学

考察了碳酸二酰胺浓度、水解反应温度以及水解时间等参数对碳酸二酰胺水解反应转化率的影响情况，得到了不同浓度、不同水解温度、不同反应时间与其转化率的关系。实验结果表明，这些因素对碳酸二酰胺水解转化率都有不同程度的影响，但水解反应温度对碳酸二酰胺的水解速率的影响最为突出。同时各影响因素的确立为制备粒径可控的纳米级微粉提供了依据。     

反应精馏水解醋酸甲酯工业化应用总结

通过对反应精馏水解醋酸甲酯过程的研究，在中试基础上进行了工业性规模应用。工业应用表明反应精馏水解醋酸甲酯是成功的，不仅醋酸甲酯水解转化率大幅度提高，而且引起回收工段的工艺更新。新的回收工艺过程具有醋酸甲酯分解率高、液体循环量小、蒸汽消耗低、循环水用量小等优点。     

醋酸甲酯催化反应精馏水解工业化应用

利用催化反应精馏的原理，对醋酸甲酯反应精馏水解过程的研究进行了工业化规模应用。工业应用表明用反应精馏水解醋酸甲酯是成功的，不仅醋酸甲酯水解转化率大幅度提高，而且引起回收工段的工艺更新。新的回收工艺过程具有醋酸甲酯分解率高，液体循环量小，蒸汽消耗低、循环水用量小等优点。     

己内酰胺水解聚合过程的计算机模拟

用文献实验数据验证了己内酰胺水解聚合过程动力学模型,并对不同反应温度下聚合产物组成（己内酰胺单体浓度与转化率、环状二聚体及水的浓度、数均聚合度和多分散性指数）进行了模拟,得到己内酰胺水解聚合过程用先高温后低温的程序控温方法,与其工业生产实际控温方法完全一致。     

催化精馏水解醋酸甲酯研究

建立了一套催化精馏的小试装置 ,对催化精馏工艺在聚乙烯醇 (PVA)生产中取代固定床工艺水解醋酸甲酯(MeOAc)进行了实验研究。对催化精馏过程中影响MeOAc水解效果的 3个主要因素 :进料水酯比Rm,回流进料比Rf 及空速S ,进行了较详细的讨论 ,并与固定床工艺的水解效果进行了对比。结果表明 ,与固定床工艺相比 ,采用催化精馏工艺水解MeOAc可以大幅提高MeOAc转化率 ,并节省大量能量     

树脂环催化剂在乙酸甲酯催化水解精馏中的应用

用压制的离子交换树脂环催化剂在催化精馏塔中进行了乙酸甲酯水解的实验研究,获得了水解转化率及沿塔高浓度分布的稳态结果。采用基于传递理论的非平衡级模型对催化水解精馏过程进行模拟,得到了与实测数据吻合妨好的模拟结果。并与前期工作以均相阳离子交换膜为催化剂所得的测定结果进行了对比,考察了新型催化剂填料－树脂压制环的优越性。     

H酸连续化合成工艺综述

本文简单介绍了H酸的传统合成工艺,并指出了该工艺存在的问题.综述了国内外有关H酸生产的新工艺.认为精萘连续磺化、硝化、催化加氢还原、选择性催化水解制备H酸是未来发展方向.     

催化精馏技术及其模拟计算

叙述了催化精馏技术的原理及其在酯化、水解、烷基化等反应中的应用,介绍了催化精馏过程的模拟模型,重点阐述了催化精馏模拟计算的应用,并对模拟软件在催化精馏模拟计算中的应用进行了阐述,应用Aspen Plus、ChemCAD等软件能较好地模拟催化精馏过程。     

Experimental Studies on the Catalytic Distillation for Hydrolysis of Methyl Acetate

In this paper, the feasibility of applying catalytic distillation for the hydrolysis of methyl acetate is studied experimentally. An optimum technological process for the hydrolysis is determined, based on experimental results and mathematical simulations. The methyl acetate conversion can be greatly increased, and the energy consumption reduced, for certain operation conditions via the catalytic distillation process.     

催化精馏塔通用数学模型及其求解方法

建立了醋酸甲酯水解反应精馏实验流程,并探讨了反应精馏的工艺特点和可行性。建立了催化精馏塔通用数学模型,并给出了求解方法。该模型对于化学反应和精馏分离同时进行及交替进行两种形式的催化精馏塔均能适用,且可用于催化精馏塔的动态分析。     

一种新催化体系的构建及其催化活性研究

用一种配体(5,5,7,12,12,14-六甲基-1,4,8,11-四氮杂环十四烷-N'-乙酸)和镧离子(Ⅲ)构建了一种新的催化体系,并用于催化对硝基苯酚磷酸二酯(BNPP)水解裂解。利用紫外-可见分光光度法研究了BNPP的催化水解的动力学。实验结果表明:这种新催化体系与其他相似的镧离子体系相比表现出更高的活性、水溶性和稳定性,在这一体系作用下,BNPP催化水解的速率比其自水解的速率提高了107倍左右。光谱分析表明,催化体系的活性物种是由镧离子和配体构成的大环配合物。     

催化精馏塔通用数学模型及其求解方法

建立了醋酸甲酯水解反应精馏实验流程,并探讨了反应精馏的工艺特点和可行性。建立了催化精馏塔通用数学模型,并给出了求解方法。该模型对于化学反应和精馏分离同时进行及交替进行两种形式的催化精馏塔均能适用,且可用于催化精馏塔的动态分析。     

Hydrolysis of methyl acetate via catalytic distillation: Simulation and design of new technological process

An equilibrium stage model was developed for the simulation of the catalytic distillation process of methyl acetate (MeOAc) hydrolysis. In the model, the influences of the reactive kinetics, residence-time, liquid holdup, and separation efficiency of the catalytic packing were considered. The model predicted the conversion of MeOAc and the mass ratio of acetic acid to water in the hydrolysis mixture. The predictions were in good agreement with experimental data. A novel process was designed based on the results of theoretic analysis and the simulation research. This new process had a higher conversion of MeOAc compared with the results in previous research and was found to be energy efficient. Optimal effect parameters and design factors of new technology on energy consumption and conversion were also determined and summarized as the following: the position of side draw is 18th to 19th stages, the catalytic distillation (CD) column pressure is at 350 kPa, the volume ratio of reflux to feed is 6–8, mole ratio of feed water to MeOAc is 3.5–4.5, and the mass ratio of side withdrawal to feed is 0.32–0.34.     

The Catalytic Mechanism of Pdx2 Glutaminase Driven by a Cys-His-Glu Triad: A Computational Study

The catalytic mechanism of Pdx2 was studied with atomic detail employing the computational ONIOM hybrid QM/MM methodology. Pdx2 employs a Cys-His-Glu catalytic triad to deaminate glutamine to glutamate and ammonia – the source of the nitrogen of pyridoxal 5’-phosphate (PLP). This enzyme is, therefore, a rate-limiting step in the PLP biosynthetic pathway of Malaria and Tuberculosis pathogens that rely on this mechanism to obtain PLP. For this reason, Pdx2 is considered a novel and promising drug target to treat these diseases. The results obtained show that the catalytic mechanism of Pdx2 occurs in six steps that can be divided into four stages: (i) activation of Cys₈₇, (ii) deamination of glutamine with the formation of the glutamyl-thioester intermediate, (iii) hydrolysis of the formed intermediate, and (iv) enzymatic turnover. The kinetic data available in the literature (19.1–19.5 kcal mol⁻¹) agree very well with the calculated free energy barrier of the hydrolytic step (18.2 kcal.mol⁻¹¹), which is the rate-limiting step of the catalytic process when substrate is readily available in the active site. This catalytic mechanism differs from other known amidases in three main points: i) it requires the activation of the nucleophile Cys₈₇ to a thiolate; ii) the hydrolysis occurs in a single step and therefore does not require the formation of a second tetrahedral reaction intermediate, as it is proposed, and iii) Glu₁₉₈ does not have a direct role in the catalytic process. Together, these results can be used for the synthesis of new transition state analogue inhibitors capable of inhibiting Pdx2 and impair diseases like Malaria and Tuberculosis.     

醋酸甲酯催化精馏水解过程模拟

利用醋酸甲酯水解体系热力学、水解反应动力学以及催化填料的基础数据,采用化工流程模拟与分析的方法,系统地对醋酸甲酯催化精馏水解过程进行了模拟研究。通过与实验数据进行对比,验证了该模拟方法的正确性。通过对工艺条件的灵敏度分析,获得该过程较优的工艺参数。在对现有工艺流程模拟的基础上,结合工业实际操作,提出两种工艺改进方案。