A kinetic model for glycerol chlorination in the presence of acetic acid catalyst

A kinetic model for the chlorination of glycerol with hydrochloric acid in the use of acetic acid as catalyst is presented in this study. The model is based on a comprehensive chlorination mechanism, taking the formation of 1,3-dichloro-2-propanol and 2,3-dichloro-1-propanol into account while ignoring the formation of any intermediate in the chlorination system. Simulations were carried out under different chlorination conditions to calculate the concentrations of the main chemical species in the reaction system. The validity of the model was examined via a comparison of the calculated data with the experimental data on the chlorination of glycerol with hydrochloric acid at 363–393 K. The results show the model is capable of describing the chlorination performance with good agreement with experimental data.     

In situ chlorination of poly(vinyl chloride) in aqueous hydrochloric acid

Based on environmental, safety, corrosion and technological considerations a new method has been developed for chlorination of PVC in aqueous hydrochloric acid solvent by controlled electrolytic in situ generation of chlorine using graphite and chlorine-selective Ti-RuO₂ electrodes. The byproduct, HCl gas, is dissolved at the moment of its formation and acts as starting material of further chlorination. This way, the application of corrosive chlorine gas is avoided. The chlorination conditions have been optimized. The highest chlorine content was found at 5.5 h reaction time using a graphite electrode. The obtained chlorinated PVC did not contain any CCl₂ units.     

盐酸水解玉米秸秆木聚糖的动力学研究

对稀盐酸水解秸秆半纤维素生成木糖水解液过程进行动力学研究。分别测定了不同温度下,不同水解时间水解液中木糖质量浓度以及其降解产物糠醛的质量浓度。利用Saeman模型拟合木糖生成过程。实验表明,该模型能够较好地描述木糖生成过程以及其降解产物糠醛的产生过程。通过曲线拟和确定了不同水解温度下木糖的生成速率以及分解速率常数,同时利用Arrhenius方程确定木糖生成活化能Ea为116 kJ/mol。综合比较不同温度下水解液中的木糖以及糠醛质量浓度,确定使用质量分数为2%的稀盐酸于120℃下水解60 min为最佳水解条件。其水解液中木糖质量浓度可达20.99 g/L,糠醛质量浓度可维持在1.46 g/L以下。     

由氯乙酸副产盐酸精制高纯盐酸

开发研究了氯乙酸副产盐酸的精制工艺及盐酸中有机杂质的紫外分光光度分析方法。副产盐酸经酸洗、吸收、蒸馏得高纯盐酸。中试结果表明 ,工艺合理 ,精制盐酸达到GB 32 0 - 93规定的工业用合成盐酸标准     

硅灰石与盐酸反应模式研究

硅灰石与盐酸在pH＜7条件下有两种反应模式反应体系pH≥3时为慢速反应,形成包覆式反应模式;反应体系pH≤1.5时为快速反应模式.并从反应产物颗粒形态、粒径分布、比表面积及反应动力学规律证实了这两种模式.     

采用盐酸解吸工艺处理副产盐酸

阐述了盐酸解吸的原理、工艺、设备、操作及开车过程中出现的问题及所采取的措施。     

废盐酸替代工业盐酸用于飞灰处置线的试验研究

北京市废酸年产量3万～5万t左右,主要有浓硫酸与氢氟酸混合液、盐酸与有机四氯化钛混酸、醋酸有机废酸、氢氟酸与硝酸混酸等,这些废酸处理困难。本文介绍了将废盐酸用于中和飞灰处置线碱性废水,进行了实验室小试和处置线中试,试验结果证实废盐酸可以替代工业盐酸。废酸资源综合利用于飞灰处置技术中,在降低飞灰处置线成本的同时,可以实现固体废物的综合利用,减少高浓度废酸和飞灰堆存带来的环境和安全问题,完全符合国家政策导向和社会发展的需求。     

气相色谱法测定甘油氯化反应中产品及中间体含量

使用气相色谱进行甘油制备环氧氯丙烷过程中产品以及中间体的定量分析。色谱柱为Dexsil-300填充柱,色谱分离在程序升温条件下进行。分别采用了面积归一化法、校正因子法与内标法对甘油、二氯丙醇以及一氯丙二醇进行了定量,并进行了比较。结果表明,使用Dexsil-300填充柱与毛细柱相比,分析时间短;内标法与其它两种方法相比,不受其它副产物影响,准确性高,重现性好。甘油、二氯丙醇及一氯丙二醇含量测定的相对标准偏差分别为1.06%,1.17%以及1.18%,回收率分别在98.70%～101.11%,98.17%～102.56%以及97.61%～102.88%之间,能够准确的反映反应进行的程度。     

Interaction of khibins titanomagnetite concentrate with hydrochloric acid

The interaction of Khibins titanomagnetite concentrate (TMC) with hydrochloric acid solutions has been investigated. The decomposition of TMC in the HCl solutions has been optimized using factorial experimental design. The main factors in the efficiency of TMC decomposition with hydrochloric acid and in metal extraction into the filtrate are the HCl concentration, HCl input, processing temperature, and reaction mixture stirring time. By varying the decomposition conditions, it is possible to control the selectivity of the process: in TMC decomposition at a high temperature and a high acid concentration and input (t = 95°C, C _HCl = 320?340 g/L, TMC (S): HCl (L) = 1: 10, τ = 4 h), the metals pass collectively into the solution with a large recovery factor (93–95%); at smaller values of the above parameters (t = 50?80°C, C _HCl = 200–220 g/L, S: L = 1: 6–7, τ = 2 h), TMC decomposition proceeds more selectively towards iron and vanadium leaching into the solution with the minimum possible leaching of titanium (<15%).     

臭氧氧化对甲基苯磺酸的动力学模型

选用典型制药中间体对甲基苯磺酸(p-TSA)作为模型污染物,研究了臭氧氧化技术对p-TSA的直接氧化和间接氧化效果。结果表明,在pH为2～13、臭氧流量16～64 mg·min^-1和污染物浓度100～5000 mg·L^-1条件下,臭氧氧化p-TSA均符合拟一级动力学降解规律,且pH、臭氧投加量的增大都有利于拟一级动力学常数的提高,而初始污染物浓度的提高则抑制拟一级动力学常数的增大。建立了表征臭氧氧化过程中直接反应和间接反应各相对贡献率的动力学模型,定量研究了臭氧流量、相似文献   

甲氧胺盐酸盐的含量测定方法

提出了以酚酞为指示剂，氢氧化钠为滴定剂测定甲氧胺盐酸盐含量的方法。测定了甲氧胺盐酸盐的离解常数Ka，考察了干扰因素对测定的影响。结果表明，干扰物质NH4Cl在样品中的含量小于5％不影响测定。该方法具有简便、快速，准确等特点,测定了数批样品结果较满意。     

动态扩散渗析法回收盐酸的实验与模型分析

近些年来,工业废酸的处理和回收逐渐成为困扰研究者的难题,膜分离技术以诸多优势成为研究重点.扩散渗析作为一种低能环保的膜分离技术,在废酸回收领域运用广泛,酸回收率一直是扩散渗析过程的重要指标.本工作以0.5～5mol/L盐酸为原料进行动态扩散渗析实验,考察进料酸浓度、进料流量(6～20mL/min)、水酸流量比(0.6～...     

盐酸尾气的治理经验

介绍了大连染料化工有限公司治理盐酸尾气的经验.     

盐酸浸出钛石膏实验研究

钛石膏是钛白粉生产过程中利用石灰中和钛白废酸而形成的一种工业固体废弃物。同时由于钛石膏含有多种有价金属元素,也是重要的二次资源,必须加以回收利用。利用盐酸浸出钛石膏,回收有价金属元素,实现钛石膏的综合利用。研究了盐酸浓度、浸出温度、浸出时间以及液固质量比等因素对浸出效果的影响。实验结果表明,在盐酸质量分数为15%、浸出时间为60 min、浸出温度为90 ℃、液固质量比为6∶1时,金属铁的浸出率>90%。该处理工艺流程简单,处理成本低,为钛石膏的利用提供一种新途径。     

盐酸体系汽液平衡及稀盐酸处理方法的研究进展

国内化工及相关行业每年产生数千万吨稀盐酸需要处理并循环使用,因此,稀盐酸处理方法的研究近年来一直受到高度的重视。盐酸体系的汽液平衡及其盐效应下的汽液平衡对于研究稀盐酸处理方法具有重要意义。文中总结了HCl-H_2O二元体系、HCl-H_2O-盐三元体系的汽液平衡以及汽液平衡数据的关联计算。阐述了常规解吸法、压差法、萃取精馏法、组合法和多效膜蒸馏过程等稀盐酸处理方法的研究现状和进展。针对目前稀盐酸处理方法,提出了基于组合法处理稀盐酸的新方法,对研究废稀盐酸处理方法具有一定的指导意义。     

副产稀盐酸吸收含氯化氢尾气制取工业盐酸

ADC发泡剂副产稀盐酸经喷射泵吸收氯乙酸尾气(主要含氯化氢)制得工业盐酸.该方法既减少废水排放,又充分利用资源,值得在氯碱行业推广.     

Direct preparation of dichloropropanol from glycerol and hydrochloric acid gas in a solvent-free batch reactor: Effect of experimental conditions

Solvent-free direct preparation of dichloropropanol (DCP) from glycerol and hydrochloric acid gas was carried out in a batch reactor with a variation of reaction conditions (agitation speed, reaction time, reaction temperature, and reaction pressure), amount of H₃PW₁₂O₄₀ catalyst, and amount of water absorbent (silica gel blue). The reaction was conducted at high agitation speed in order to avoid mass transfer limitation between glycerol and hydrochloric acid gas. In the direct preparation of DCP from glycerol and hydrochloric acid gas, DCP formation was increased with increasing reaction time, reaction temperature, and reaction pressure. Chlorination of glycerol occurred via the following consecutive reaction steps: glycerol→monochloropropanediol (MCPD)→dichloropropanol (DCP)→trichloropropane (TCP). Reaction rate decreased in the order of first-step reaction>second-step reaction>third-step reaction. The presence of H₃PW₁₂O₄₀ catalyst and water absorbent (silica gel blue) enhanced the formation of DCP. DCP formation was increased with increasing the amount of H₃PW₁₂O₄₀ catalyst and water absorbent (silica gel blue). Strong Brönsted acid site of H₃PW₁₂O₄₀ catalyst and water removal from the reaction system favorably served in improving DCP formation.     

盐酸生产总结

针对盐酸生产中出现的问题实施整改措施,实现了稳定生产。     

Determination of glycerol by oxidation with periodic acid

Summary An acidimetric procedure for the determination of glycerol following oxidation with periodic acid has been described. This procedure has been successfully applied to C. P. grade glycerin, spent soap lyes, soap lye crudes, half crudes, saponification crudes, evaporator salt, and mixtures of glycerol with trimethylene glycol and polyglycerols. Factors that influence the determination, such as size of sample, presence of salt and the presence of organic compounds containing hydroxyl groups, have been discussed.