Kinetics and Mechanism of Hydration of Acrylic Acid over Ion-exchanged Resin:Experimental Exploration and DFT Calculation

Liquid-phase acrylic acid hydration over solid-phase catalysts is a key reaction for the industrial productionof 3-hydroxypropionic acid. However, the relevant literature primarily focuses on the experimental aspects of catalystscreening and exploring reaction conditions, with few accurate descriptions of the reaction kinetics and determination ofthe reaction mechanism. Here, we combined kinetics experiments and theoretical calculations to elucidate the kinetics andmechanism of acrylic acid hydration on a resin catalyst. The pseudo-homogeneous model, and Langmuir-Hinshelwood-Haugen-Watson and Elie-Riedel (ER) heterogeneous models were used to explain the experimental kinetics data. TheER model can explain the experimental data very well, suggesting strong adsorption of acrylic acid on the surface of theresin catalyst. Furthermore, density functional theory calculations show that the hydration follows a stepwise, rather than aconcerted, reaction pathway. The present study provides theoretical insights into the reaction mechanism and kinetics, fillingthe gap in our understanding of the reaction on a fundamental level.

Optimizing the Synthesis of Ethyl tert-Butyl Ether in Continuous Catalytic Distillation Column Using New Ion Exchange Resin Catalyst

Liquid phase synthesis of one of the important fuel oxygenate, ethyl tert-butyl ether （ETBE）, from etha-nol and tert-butyl alcohol （TBA） has been studied in catalytic distillation column （CDC） using ion exchange resin catalyst CT-145H. A packed CDC of 1.2 m height and 50 mm diameter with indigenously developed reactive sec-tion packing was used to generate experimental data. Effect of different key variables on product purity in distillate, was investigated to find the optimum operating conditions for ETBE synthesis. The optimum conditions for 0.2 kg·s-1 of ethanol feed were found：reboiler duty of 375 W, molar feed ratio of 1︰1.3 of reactants, and reflux ratio of 7. Concentration profiles for each component along each column section at optimum conditions were also drawn. Neither output nor input multiplicity was observed at experimental conditions.

Preparation of Low Cost Activated Carbon from Deactivated Resin Catalyst for Methyl Tert-Butyl Ether Synthesis and Its Application in Dimethyl Sulfide Adsorption with Transition Metal Impregnation

In this paper, a low-cost activated carbon(AC) was prepared from deactivated resin catalyst(DRC) for methyl tert-butyl ether(MTBE) synthesis through carbonization and subsequent steam activation treatment. The activated carbon was characterized in detail. After loading various transition metals, including Cu^(2+), Ag+, Co^(2+), Ni^(2+), Zn^(2+), and Fe^(3+) via the ultrasonic-assisted impregnation method, a series of metal-loaded adsorbents(xM-AC) were obtained and their dimethyl sulfide(DMS) adsorption performance was investigated in a batch system. Among these adsorbents, 15Cu-AC presented a superior DMS adsorption capacity equating to 58.986 mg/g due to the formation of S-M(σ) bonds between Cu^(2+) and sulfur atoms of DMS as confirmed by the Raman spectra and kinetic study.

THE EFFECT OF THE ACID CATALYST ON THE PREPARATION OF MQ SILICONE RESINS

MQ silicone resins were prepared through hydrolytic condensation of ethyl polysilicate or tetraethoxysilane and hexamethyl disiloxane. The unit ratio of the MQ resins was determined by Si-29-NMR. The relationship of the unit ratio of the product resins with that in the feed was studied. When the reaction was catalyzed by aqueous hydrochloric acid, and the unit ratio of M to Q in the feed was more than 1, the unit ratio of the product was usually lower than that of the feed. The MQ silicon with an unit ratio of M/Q > 2 could not be obtained. However, if the reaction was catalyzed by concentrated sulfuric acid and the reverse hydrolysis process was employed, MQ silicone resin with very high M/Q ratio was successfully prepared.

EFFECT OF CATALYST ON THE REACTION BETWEEN ACTIVE ESTER AND EPOXY RESIN

In this study the third amine and phosphine were selected as the catalysts of epoxy resin, the influence of these catalysts on curing reaction was observed in comparison with the former selected quadrupole onium salt and the influence of them on physical properties of solidified matter was also studied. (Author abstract) 10 Refs.

Investigating the Effect of Catalyst Type and Concentration on the functional Group Conversion in Castor Seed Oil Alkyd Resin Production

Significant scientific and economic benefits may be derived from investigating the best choice of catalyst in the alkyd resin synthesis. The effect of catalyst type and concentration on the production of alkyd resin using castor seed oil (CSO) was evaluated. Lithium hydroxide, lead (II) oxide, calcium carbonate, sodium hydroxide and calcium oxide were investigated. The fatty acid profile of the raw CSO was determined using GC-MS while structural elucidation of the CSO based alkyd resins was determined using FTIR spectrometry. The CSO modified alkyd resin produced has acid values of 5.0, 5.61, 7.0 8.24 and 11 for lithium hydroxide, lead (II) oxide, calcium carbonate, sodium hydroxide and calcium oxide respectively. The extent of reaction was 95%, 95%, 91%, 89% and 88% for lithium hydroxide, lead (II) oxide, calcium carbonate, sodium hydroxide and calcium oxide respectively at the reaction time of 150 minutes. The alcoholysis reaction completion time was fastest in LiOH followed by PbO, CaCO3, NaOH and CaO catalyst. Physico-chemical parameters of the oil and performance evaluation of the alkyd films suggest that they are sustainable materials for surface coating. LiOH shows excellent robustness to expanded process parameters.

一种耐酸耐碱高强树脂的合成及性能

小套管二次固井是一种新型的固井工艺,针对目前由于水泥自身脆性大易气窜和水窜且为碱性固化体、易受压产生裂缝、易受酸性介质破坏的问题,以D-33二元醇和顺丁烯二酸为原料,苯乙烯作为活性稀释剂合成了一种不饱和型聚酯树脂。在树脂体系中引入填料,提高产品韧性及抗压强度。采用傅里叶变换红外光谱仪对树脂进行表征;通过万能试验机对树脂体系进行性能评价。结果表明,目标产物包含羰基、碳碳双键和苯环对位取代结构的特征峰,固化体系为过氧化二苯甲酰/N,N-二甲基苯胺,其在50℃、60℃和70℃条件下的添加量分别为0.2%/0.02%、0.1%/0.02%、0.1%/0.01%,万能试验机测试结果显示,在50℃、60℃和70℃下养护24h后的抗压强度分别约为50MPa、70MPa、90MPa。实验获得了一种聚合时间可调、黏度小、抗压强度高且耐酸耐碱的固井材料,有望在水平井重复压裂改造中大规模使用。

树脂载钯双功能催化剂的制备及其催化碳四烯烃临氢叠合反应

基于碳四烯烃叠合反应工艺,设计并制备了酸性树脂(KC110、Amberlyst35)载钯双功能催化剂,用于一步法催化1,3-丁二烯选择性加氢和异丁烯叠合反应。借助电子微区探针分析(EPMA)、N 2物理吸附-脱附(BET)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)等手段对其物化性质进行表征,并进一步考察了双功能催化剂在碳四烯烃临氢叠合反应过程中的催化性能。结果表明:0.10%Pd/KC110双功能催化剂负载的钯纳米颗粒主要分布在树脂大孔表层结构,平均粒径为3~10 nm,且树脂载体本身的酸性和孔结构保存完好;在反应温度为25℃、压力为1.4~1.6 MPa、质量空速为2.7 h-1、氢气/丁二烯摩尔比为1.5的条件下进行0.10%Pd/KC110催化碳四烯烃临氢叠合反应,1,3-丁二烯可以完全脱除,异丁烯转化率高于81.5%,叠合产物中碳八选择性为75.1%。

催化剂对基于动态酯交换Vitrimers材料性能的影响

传统环氧树脂作为干式变压器、电压互感器和复合绝缘子等电工装备的主要原材料,有着良好的力学性能和电学性能,但是其固化后形成的交联网络难溶难熔。随着环氧树脂基电工装备运行年限的增长,大量退役设备的处理面临巨大的挑战。该文制备了基于酯交换的酸酐固化类玻璃化环氧树脂材料(Vitrimers),系统地研究了催化剂对树脂力学、电学、热学以及动态交换性能的影响规律,并使用醇类溶液探索其降解性能。研究结果显示,与传统环氧树脂相比,Vitrimers体系的断裂伸长率较高,表现出良好的韧性。在Vitrimers体系中以1,5,7-三叠氮双环(4.4.0)癸-5-烯(TBD)为催化剂的Vitrimers具有较佳的综合特性,在高温下表现出良好的应力弛豫特性,且能够在7h(190℃)全部溶解于乙二醇(EG)溶液中。该文研究结果表明,类玻璃化环氧树脂有较综合的力-热-电特性,能够快速溶解于降解溶液,有望用作电工装备的新型环保树脂基体。

甲醇制乙酸工艺中降低杂质离子浓度的研究进展

乙酸是合成乙酸乙烯、乙酸酯、乙酸酐和氯乙酸等有机化合物的关键原料。甲醇羰基化制备乙酸是目前的主流工艺,然而在反应液中微量的杂质离子对催化剂的活性和稳定性产生重大的影响。以当前主流的Cativa工艺(铱基均相催化体系)为例,分析了杂质离子的来源及其对催化剂性能的负面影响。综述了当前采用的杂质离子处理策略,并着重介绍了离子交换树脂技术在杂质离子去除中的应用。从而为甲醇羰基化制备乙酸的正常生产提供一定的参考。

C9PR加氢催化剂孔道要求及其制备的研究进展

综述了适合于C9石油树脂(C9PR)加氢催化剂孔道结构的要求、孔道结构的制备及调节方法,并提出需加快对C9PR加氢催化剂孔道结构的研究。

催化剂BCE-H 200在高密度聚乙烯装置上的应用

在中韩(武汉)石油化工有限公司Hostalen ACP高密度聚乙烯装置上,采用国产催化剂BCE-H 200分别替代进口催化剂Z 501和Z 509生产了高密度聚乙烯注塑料和薄膜料。分析对比了3种催化剂的活性及粉料粒径分布、堆积密度,并对生产的注塑料和薄膜料进行了表征分析。结果表明:BCE-H 200的活性较Z 501低13.8%,较Z 509高49.2%,其氢调敏感性较Z 501和Z 509低;BCE-H 200生产注塑料和薄膜料时,粉料的粒径分布比进口催化剂Z 501和Z 509更集中,细粉更少,但堆积密度低;采用催化剂BCE-H 200替代催化剂Z 501生产的注塑料刚性较高,韧性较低,相对分子质量分布更宽;采用催化剂BCE-H 200替代催化剂Z 509生产的薄膜料,力学性能变化不大,相对分子质量分布更宽。

预涂彩板棕色面漆冲击性能提升研究

通过对基料树脂种类、交联树脂种类、颜基比和催化剂种类的实验,研究各因素对棕色面漆的冲击性能的影响。实验结果表明,当基料树脂为C-19聚酯树脂、交联树脂为高甲醚化三聚氰胺树脂(Cymel303)、颜基比控制在(0.2~0.3)∶1、催化剂为封闭型酸催化剂A时,棕色面漆耐冲击性能达到最佳且综合性能不受影响。

Change of asphaltene and resin properties after catalytic aquathermolysis

Resin and asphaltene were separated from Liaohe heavy oil. Catalytic aquathermolysis of asphaltene and resin was investigated by using water soluble catalysts （NiSO4 and FeSO4） and oil soluble catalysts （nickel naphthenate and iron naphthenate）. Before and after aquathermolysis, the properties of the resin and asphaltene was compared by means of ultimate analysis, vapor pressure osmometer （VPO） average molecular weight, X-ray diffraction （XRD）,^13C and ^1H nuclear magnetic resonance （NMR）. The conversion sequence was as follows： No-catalyst〈NiSO4〈FeSO4〈nickel naphthenate〈iron naphthenate. In the presence of catalysts, the amount of H2 and CO increased significantly, while H2S in the gas product decreased. The molecular weight of asphaltene and resin increased after reaction without catalyst. But the catalysts restrained this trend. The H/C ratio of asphaltene and resin decreased after reaction. From the results of average structural parameters and molecular weight, it was found that asphaltene and resin were partly aggregated after aquathermolysis.

Factor Affecting Gel Time/Process-Ability of Urea Formaldehyde Resin Based Wood Adhesives

Urea-formaldehyde (UF) resin presents the most utilized adhesive system in the manufacture of plywood, particleboard and fiberboard. At the temperatures above 100°C in the presence of hardener, this resin undergoes cross-linking reaction and the formation of three dimensional cross linked structures takes place and bonding of wood particles in a hot press [1]. UF powder resins show high reactivity and good performance in the production and by their low price;however they lack in water resistance of the hardened resin [2]. Urea-formaldehyde (UF) resins are the most important type of adhesive resins for the production of wood based panels but process-ability and curing behavior of urea formaldehyde resin depended on various factors related to resin properties, types of wood and their properties, amount & type of catalyst, types and amount of polymers addition and environmental conditions [3]. This factor decides the process-ability of UF resin based composite during manufacturing of plywood, particle board and fiberboard. In this review paper, various factors affecting gel time and process-ability of UF resin based wood composite are reviewed.

D301 resin as a solid base for phosphine-free Heck reactions with heteroaryl halides

A new and practical method of the D301 resin,a weak basic anion exchange resin with secondary amine functionality（Grade Matrix Structure：Styrene-DVB D301R）,used as base to Heck reactions catalyzed by palladium reagent without phosphine compound as ligand is described.It was found that the D301 resin used as base is an efficient and reusable base and can be regenerated and recycled in the reaction.The olefmation of heteroaryl halides prepared the corresponding products in good yields using D301 resin as base.

Immobilized Ruthenium Catalyst for Carbon Dioxide Hydrogenation

Three kinds of cross linked polystyrene resin （PS） supported ruthenium complexes were developed as catalysts for the synthesis of formic acid from carbon dioxide hydrogenation. Many factors, such as the functionalized supports, solvents and ligands, could influence their activities and reuse performances greatly. These immobilized catalysts also offer the industrial advantages such as easy separation.

阳离子交换树脂催化合成乳酸甲酯动力学研究

工业化生产乳酸甲酯需要特定催化剂的动力学数据进行模拟计算.本文研究了在大孔阳离子交换树脂DA330的催化作用下,乳酸和甲醇生成乳酸甲酯的反应动力学.乳酸甲酯是一种重要的化工生产基础原料,多用来作为合成香料和农药的原料.随着化石能源紧缺和环保要求提高,具有可降解和可再生特性的乳酸甲酯及其高聚物的需求也在与日俱增.乳酸甲酯的连续化生产是提高乳酸甲酯产量的关键,具有广阔的研究前景.采用固体大孔阳离子交换树脂代替传统浓硫酸作为催化剂,需要对动力学方程进行重新测定.本文针对乳酸甲酯反应体系外扩散影响、内扩散影响、酯化反应动力学、水解反应动力学分别进行了实验.采用气相色谱对反应体系中的乳酸甲酯含量进行测定.研究发现内、外扩散在实验条件范围内对反应速率无明显影响:以酯化反应为例,搅拌转速达400 r/min以上时体系内催化剂颗粒悬浮程度达到峰值,外扩散不影响酯化反应速率;在催化剂颗粒悬浮程度达到峰值之后,催化剂粒径大小不影响酯化反应速率.反应温度在实验范围内对反应速率呈现显著的正相关影响,酯化和水解实验数据拟合均符合Quasi-Homogeneous模型,最终得到DA330催化条件下的反应动力学.

醛酮树脂基非金属催化剂催化氧气氧化苯制备苯酚

苯酚是一种具有广泛应用价值的化工原料,氧气直接氧化苯制备苯酚是一条绿色的路径。本文设计并制备了一种新型醛酮树脂基非金属催化剂用于氧气直接氧化苯制备苯酚。通过X射线衍射仪、傅里叶变换红外光谱仪、扫描电镜、X射线光电子能谱和N_(2)吸附-脱附等技术对催化剂的形貌、结构进行了表征。结果表明,制备的催化剂是具有大量羟基和羰基官能团的无定形碳材料,不同的酮对催化剂官能团的含量有影响。考察了所制备的催化剂催化氧气直接氧化苯制备苯酚反应的性能,优化了反应条件。在最佳反应条件下,苯酚的产率达到16.3%,其催化性能可与金属催化剂相媲美。此外,通过动力学研究表明该反应为一级反应并计算了各步骤的反应速率常数。结合表征、动力学实验和对照实验得出催化剂表面丰富的酮羰基是反应的活性位点,并据此提出了反应机理。

异辛烯与苯酚烷基化反应催化剂的制备及性能

以树脂为催化剂,进行异辛烯与苯酚烷基化制备对特辛基酚的研究。考察酚烯比、催化剂用量、反应温度和反应时间等对烷基化反应的影响,确定烷基化反应的最佳工艺条件。在苯酚与异辛烯物质的量比4∶1、催化剂用量2%、反应温度80℃和反应时间5 h条件下,异辛烯转化率为99.7%,对特辛基酚选择性为90.3%。重复性试验表明,该树脂催化剂具有较好的反应稳定性。