反应条件对甲基氯硅烷合成的影响

以硅粉、氯甲烷为原料,借助搅拌床反应器模拟工业装置合成甲基氯硅烷,研究了反应温度、硅粉平均粒径、氯甲烷质量流量3个因素对甲基氯硅烷合成的影响。结果表明:反应温度对合成的影响最显著。以二甲选择性为评价指标时的最佳工艺条件为反应温度300℃、硅粉平均粒径110μm,氯甲烷质量流量为625 g/h;以触体产率为评价指标时的最佳工艺条件为反应温度320℃、硅粉平均粒径60μm,氯甲烷质量流量为625 g/h。     

压力对甲基氯硅烷合成系统的影响

以两套80 kt/a甲基氯硅烷合成装置为研究对象,探讨了反应压力对氯甲烷空床线速度、硅-铜触体转化率、氯甲烷单级转化率及二甲选择性的影响。结果表明,压力为0.23 MPa时,氯甲烷空床线速度较高,反应温度更易实现平稳控制,同时可获得更高的硅-铜触体转化率及氯甲烷单级转化率,但二甲选择性却较0.30 MPa时低。     

铜基催化剂在甲基氯硅烷直接合成过程中的工艺特性

在搅拌床反应器中使用铜基催化剂(辅以少量Zn, Sn, P助剂)催化硅粉与氯甲烷反应合成甲基氯硅烷,考察了温度、压力和催化剂用量对反应速率和产物选择性的影响. 结果表明,在温度320℃、压力0.1 MPa条件下,平稳期的催化反应速率可达210 g/(kg×h),二甲基二氯硅烷的选择性可达87.7%;升高温度可大幅提高反应速率,但超过330℃会显著降低反应选择性;压力在0.3 MPa以下反应速率对氯甲烷近似为一级反应,选择性受压力影响较小;一定范围内增加催化剂用量可提高速率,但会缩短反应平稳期,造成硅粉利用效率下降.     

单体合成中影响甲基氯硅烷产品质量的因素分析

分析了甲基氯硅烷合成反应中硅粉、氯甲烷、催化剂及助剂、温度、压力等因素对二甲基二氯硅烷质量的影响,给出了提高二甲基二氯硅烷产品质量一些建议。     

微型固定床反应器合成甲基氯硅烷工艺条件的研究

利用微型固定床反应器研究了直接法合成甲基氯硅烷过程中温度、压力对二甲基二氯硅烷的收率和硅粉转化率的影响。结果发现:升高反应温度、增加反应压力可以缩短诱导期,增大反应速率,硅粉转化率和二甲基二氯硅烷收率也得到提高,但过高的温度和压力会使二甲基二氯硅烷的选择性下降。此反应体系的较佳温度为320℃,压力为0.4 MPa。     

环体Cl－含量不合格原因分析

环体Ｃｌ－含量不合格原因分析温峻（吉化电石厂有机硅车间１３２０２２）１前言我车间主要产品是以甲醇和氯化氢为原料，在氯化锌催化剂作用下生成氯甲烷；氯甲烷再与硅粉在催化剂存在下反应生成甲基氯硅烷混合单体；混合单体经分馏分离出甲基三氯硅烷（以下简写Ｍ１），...     

反应物料对微型固定床反应器合成二甲基二氯硅烷的影响

利用微型固定床反应器,研究了直接法合成二甲基二氯硅烷的反应过程中硅粉质量、硅粉粒径及一氯甲烷流量对二甲基二氯硅烷的影响。结果表明,硅粉中杂质含量升高,反应出口气体中二甲基二氯硅烷的含量随之降低,硅粉中的Fe含量是影响二甲基二氯硅烷的主要因素;较小的硅粉粒径有助于反应初期缩短诱导期,但随反应的进行,硅粉的转化率和二甲基二氯硅烷的含量会下降;增加一氯甲烷流量,反应诱导期增长,硅粉转化率和二甲基二氯硅烷的含量均减小,但较小的流量在反应后期会出现二甲基二氯硅烷的含量严重下降的现象。     

直接法合成甲基氯硅烷反应启动的研究

阐述了在流化床反应器中,氯甲烷气体和硅粉颗粒进行气固相反应,直接合成甲基氯硅烷的生产原理,及反应过程中反应诱导期(推料升温催化剂还原期)的工艺过程和反应机理。详细描述了反应诱导期的4个工艺过程:原料硅粉的准备;反应系统的确认;赶潮、推料、升温及流化床的改通,最后提出了发展建议。     

有机硅单体合成用复合铜粉催化剂的研究

采用硅粉与氯甲烷,于直管式固定搅拌床反应器中合成甲基氯硅烷,通过计算二甲基二氯硅烷(M2)的选择性和硅转化率,评价3种复合铜催化剂的催化性能。结果表明,自产复合铜粉C的催化性能相对较佳,采用复合铜粉C的体系在整个反应期间的M2选择性均值为91.89%,硅转化率为59.24%。复合铜粉C具有更薄、更细、比表面积更高、松装密度更低、粒度更细的特点,有利于其在甲基氯硅烷合成反应中与硅粉形成更多的活性中心。     

提高单质硅生产硅溶胶硅粉转化率的研究

优化由单质硅制备硅溶胶的工艺条件,探讨了原料硅的组成对硅粉转化率的影响。反应的最佳条件为:选择硅含量≥98%,碳、氧、氮等元素含量≤0.5%的工业等外硅粉,常压,反应温度95℃,回流反应5 h,原料质量比为mH2O∶mS i∶mNaOH=100∶16.6∶0.63时,硅粉转化率最高,可达95%以上。     

无皂乳液制备PMMA动力学及其模型

以甲基丙烯酸甲酯(MMA)为单体、过硫酸钾(KPS)为引发剂进行无皂乳液聚合反应,考察了单体MMA浓度、引发剂KPS用量及聚合温度对其动力学行为的影响。建立了转化率-时间关系曲线的模型函数———Gamm a积分函数,用它拟合了转化率-时间关系曲线,获得了聚合过程的重要特征参数,如平均成核速率,聚合最大速率和平稳期平均聚合速率及成核结束和聚合进入完成期对应的转化率。同时对聚合速率与以上各聚合参数的关系数据进行了非线性拟合,得到了它们之间的关系式。拟合相关系数非常接近于1,平均拟合误差很小,成核结束时转化率在15%以内,聚合速率随以上参数增大而增大,反应温度在聚合过程中起决定作用。     

Acetic Acid from the Carbonylation of Chloride Methane Over Rhodium Based Catalysts

A new route for the indirect conversion of methane that makes use of the latest advance in methyl chloride production is reported. Acetic acid was produced from the carbonylation of methyl chloride by carbon monoxide over a variety of catalysts. The presence of promoters was crucial for the carbonylation reaction. The yield of acetic acid reached 84.7% with RhCl₃ as catalyst and PPh₃/KI as promoters. The effects of reaction temperature, carbon monoxide pressure, and reaction time were investigated. The possible reaction mechanism was discussed.     

[BMIM]Cl-nAlCl3 ionic liquid-catalyzed redistribution reaction between methyltrichlorosilane and low-boiling residue to dimethyldichlorosilane

Methyltrichlorosilane and low-boiling residue from the synthesis of methylchlorosilanes via the direct reaction of silicon and methyl chloride were effectively converted to high-valued dimethyldichlorosilane catalyzed by 1-butyl-3-methylimidazolium chloroaluminate, [BMIM]Cl-nAlCl₃, ionic liquid catalysts. The yield of dimethyldichlorosilane reached 69.1% when the redistribution reaction between methyltrichlorosilane and low-boiling residue was catalyzed by [BMIM]Cl-6AlCl₃ at a reaction temperature of 150 °C for 300 min. The conversion of methyltrichlorosilane was 87.8%. And the conversions of tetramethylsilane, methylhydrodichlorosilane, and dimethylhydrochlorosilane present in low-boiling residue were ca. 100%, respectively. The ionic liquids could be recycled efficiently. This research provided an eco-friendly and economical route for the treatment of methyltrichlorosilane and low-boiling residue, which were the by-products in the direct synthesis of methylchlorosilanes. The possible reaction route was also discussed.     

Catalytic pyrolysis of methyl chloride for ethylene and propylene production

Ethylene and propylene production via the catalytic pyrolysis of methyl chloride was studied over zeolite catalyst TsVM (the Russian analogue of ZSM-5) and silicoaluminophosphate catalyst SAPO-34. SAPO-34 is more efficient in light olefin (in particular, ethylene and propylene) formation; this catalyst provides 55–60% methyl chloride conversion at 400 and 450°C and a contact time of 3 s with the 80–85% ethylene + propylene selectivity. The ethylene selectivity at 450°C is 15% higher than at 400°C. The reaction rate for methyl chloride conversion over SAPO-34 is described by a first-order equation. The catalyst gradually loses activity during methyl chloride conversion as a result of carbonization but recovers it completely after regeneration in air at 500°C. The catalyst can be recommended for further pilot-scale testing.     

Conversion prediction in high conversion free-radical polymerizations

The objective of this article is to introduce anew general approach For conversion prediction in high-conversion free-radical polymerizations–“The Method of Kinetic Similarity.” Using a single homopolymer reference curve of methyl meth-acrylate (MMA) and one to two time-scaling parameters, the conversion vs. time curves for MM A, ethyl methacrylate (EMA), vinyl chloride (VC), acrylonitrile (AN), styrene methyl methacrylate (SMMA), and styrene acrylonitrile (SAN) could be well-described. For MMA and VC, these parameters are shown to obey expected Arrhenius relationships over 45 to 90°CC and 30 to 70°C, respectively. The method is simple to apply, continuous over the whole conversion range, utilizes existing knowledge at low and limiting conversions, and avoids application of usual low conversion assumptions into the diffusion-controlled region.     

Production of biodiesel fuel from tall oil fatty acids via high temperature methanol reaction

Tall oil fatty acids are a byproduct of the paper industry and consist predominantly of free-fatty acids (FFAs). Although this feedstock is ideal for biodiesel production, there has been relatively little study of its conversion to biodiesel. Thus, the purpose of this study was to investigate the high temperature reaction of methanol with tall oil at subcritical and supercritical pressures to produce fatty acid methyl esters. This study investigates the effects of mixing, pressure, temperature, and methanol to oil molecular ratio in order to determine the potential use of tall oil as a biodiesel feedstock. In this work, tall oil fatty acids were successfully reacted with supercritical and subcritical methanol in a continuous tubular reactor, resulting in a reaction that is primarily temperature dependent. Conversions at subcritical pressures of 4.2 MPa and 6.6 MPa were 81% and 75%, respectively. Pressure seemed to have little correlation to conversion in both regimes, and conversions were comparable between the two. Additionally, it was found that tall oil fatty acids react well with methanol to give comparable conversions at the relatively low molecular flow ratio of 5:1 methanol to tall oil. Both of these observations suggest that hydrolyzed triglycerides or free fatty acid feedstocks would make the primary high temperature biodiesel reaction and the subsequent separation and purification operations less expensive than was previously believed.     

On the gel effect in the presence of a chain transfer agent in methyl methacrylate polymerization and its copolymerization with various acrylates

The kinetics of methyl methacrylate (MMA) polymerization, and of its copolymerization with various acrylates, at high conversions in the presence of a chain transfer agent, are investigated with a dilatometer over the entire course of reaction. The displacement to higher conversions of the onset of the gel effect in the MMA homopolymerization, in the presence of a chain transfer agent, was determined. Similar information is also provided for the MMA-acrylate copolymerization systems. An increase in polymerization temperature slightly delays the onset of the gel effect in the MMA-acrylate copolymerization, but considerably increases the final conversion. The final conversion in copolymerization for a constant concentration of the chain transfer agent is independent of the initiator concentration, but is a function of the polymerization temperature. The reaction time for reaching the limiting conversion in copolymerization is increased with an increasing amount of the second monomer, as well as with an increasing number of carbon atoms in the acrylate used as the second monomer. © 1993 John Wiley & Sons, Inc.     

Synthesis of methoxysilanes by the reaction of metallic silicon with methanol using copper(II) acetate as the catalyst

The reaction of methanol with silicon was studied using various copper compounds other than the halides. Copper(II) acetate and copper(I) oxide gave high silicon conversions (82%) though the selectivities for trimethoxysilane were low (<19%). The selectivity was appreciably improved by addition of a small amount of thiophene or propyl chloride to the methanol feed.     

甲基碳酸酯季铵盐的合成与表征

研究了碳酸二甲酯与长链烷基叔胺的季铵化反应。考察了反应温度、反应时间、物料摩尔比和溶剂用量等反应条件对十二烷基二甲基叔胺季铵化反应的影响,确定了优化条件:反应温度130℃、反应时间5h、n(碳酸二甲酯)/n(烷基叔胺)=5、甲醇质量分数(相对于反应原料的质量)10%。在该条件下,不同碳链长度的单烷基叔胺的季铵化率均达到98%以上,而双碳十和双碳十八叔胺的转化率较低,分别为88.09%和68.77%。说明空间位阻是影响季铵化反应进程的重要因素,与分子空间结构模拟的结果一致。通过增加反应时间,双碳十叔胺反应7h季铵化率为98.85%,双十八烷基甲基叔胺反应12h季铵化率为95.68%。采用1HNMR与IR对合成季铵盐的结构进行了表征,结果表明,成功合成了甲基碳酸酯季铵盐。