电解法制备高纯四甲基氢氧化铵的研究

用电解 电渗析法 ,以四甲基氯化铵为原料 ,石墨为阳极 ,不锈钢为阴极 ,采用 8A/dm2 的电流密度 ,制得高纯度的四甲基氢氧化铵 ,电流效率为 79.4% ,同时研究了影响制备四甲基氢氧化铵纯度和电流效率的因素。     

长链烷基季铵碱的制备工艺及性能

以烷基叔胺和碳酸二甲酯为原料制备烷基碳酸甲酯铵,再经水解得到烷基碳酸氢铵,通过离子膜连续电解法合成长链烷基季铵碱。以十四烷基三甲基氢氧化铵为例,考察了电解反应温度、电流密度、阳极液浓度、阴极出料液浓度对电流效率的影响,得出其优化工艺条件为:反应温度65℃、电流密度450 A/m2、阳极液浓度1.40 mol/L、阴极液出料浓度为0.15 mol/L,在该条件下电解反应的电流效率可达67%以上;通过1HNMR、IR对产品结构进行了表征,结果表明,合成的产品为长链烷基季铵碱;对得到的长链烷基季铵碱的表面活性、p H值、润湿性、泡沫性等性能进行了研究。     

长链烷基季铵碱的制备工艺及性能研究

以烷基叔胺和碳酸二甲酯为原料制备烷基碳酸甲酯铵,烷基碳酸甲酯铵水解得到烷基碳酸氢铵,再通过离子膜连续电解法合成长链烷基季铵碱。以十四烷基三甲基氢氧化铵为例,考察了电解反应温度、电流密度、阳极液浓度、阴极出料液浓度对电流效率的影响,得出其最优工艺条件为：反应温度65 ℃、电流密度450 A/m2、阳极液浓度1.40 mol/L、阴极液出料浓度为0.15 mol/L,在此条件下电解反应的电流效率可达67%以上;通过1H-NMR、IR对产品结构进行了鉴定,结果表明合成的产品为长链烷基季铵碱;对得到的长链烷基季铵碱的表面活性、pH值、润湿性、泡沫稳定性等性能进行了研究。     

4-甲基吡啶直接电氧化合成异烟酸工艺条件的研究

以Ti/PbO2为阳极,Pb为阴极,硫酸溶液为电解质,在阳离子交换膜为隔膜的H型电解槽中,直接电氧化4-甲基吡啶合成异烟酸,并考察了阳极电解液中4-甲基吡啶及硫酸浓度,通电量,电流密度和温度对异烟酸收率和电流效率的影响,得到的工艺条件为阳极电解液中4-甲基吡啶和硫酸的质量分数分别为10%和25%,通电量18.65(A.h),电解电流密度60 mA/cm2,60℃,在此条件下重复试验,异烟酸平均收率达到92.2%,平均电流效率50.9%。     

双极膜电去离子过程制备四甲基氢氧化铵

采用酸室填充离子交换树脂的双极膜电去离子(BMEDI)装置,以四甲基氯化铵(TMAC)为原料制备四甲基氢氧化铵(TMAH).研究了树脂体积比、电流密度和原料浓度对TMAH制备过程的影响,并对2种不同的均相阴膜进行了对比考察.结果表明,在电流密度40 mA·cm-2,原料TMAC浓度0.1 mol·L-1的条件下,TMAH转化率可达91.2%.电流密度提高,TMAH转化率和过程能耗随之增大,在更高的原料浓度下可获得更高的电流效率,酸室填充100%阴树脂效果较好.此外,与JAM-10膜相比,UTX-UIF-A膜的面电阻较小,取得了更佳的试验效果.     

双极膜电渗析法制备高纯度四甲基氢氧化铵

为解决传统上采用电解法制备四甲基氢氧化铵(TMAH)存在着高能耗、设备腐蚀及纯度低等问题,而采用绿色环保、低能耗的双极膜电渗析装置处理四甲基碳酸氢铵(TMAHC)溶液制备四甲基氢氧化铵,以避免卤素离子对产品碱纯度的影响。采用双极膜电渗析装置进行实验,在单因素实验的基础上,设计正交实验,考察电流密度、料液TMAHC含量等对实验的影响,并进行极差分析、方差分析以及层次分析。结果表明,对电流效率的影响程度:料液TMAHC含量电流密度流量比,当料液TMAHC浓度为1.5 mol/L、电流密度为140 A/m~2、流量体积比为1:2时,电流效率可达到80.3%,收率为96.8%。     

电子级四丁基氢氧化铵的离子膜电解法制备

讨论了以四丁基溴化铵为原料,离子膜电解法制备电子级四丁基氢氧化铵的条件。实验结果表明,在电解前金属离子的脱除中,WU-64树脂具有最好的提纯效果;在电解处理单元中,当电流密度为1000A·m-2、原料浓度为0.7mol·L-1时电流效率最高;在产品的后处理过程中,可采用两室一膜电解法对产品中阴离子进行去除,可得到溴含量为0.138mg·kg-1、氯含量为0.784mg·kg-1的质量分数为15%的四丁基氢氧化铵溶液。研究结果对于微电子工业有着重要的参考价值。     

草酸电解还原制备乙醛酸的研究

研究连续草酸电解还原制备乙醛酸的过程和工艺。采用一膜两室电解面积为10cm×10cm的离子膜电解槽进行连续电解实验,比较了电极材料、阳离子交换膜材料、研究了电解液流量对电流效率的影响以及电流密度、电解温度和电解时间对电解过程的影响。结果表明以铅极板作阴极、钽-铱作阳极板、NF-1型含氟磺酸阳离子交换膜时电解的效果较好,得到的优化电解条件为:电流密度1000A.m-2,电解温度25℃,电解时间4.5h,阴极液和阳极液流量均为2L.min-1。在此条件下的电耗为3038.9kWh.t-1产品,研究结果可为工业化设计提供参考数据。     

甲基三乙基碳酸氢铵的合成工艺研究

甲基三乙基氢氧化铵是电子、催化等领域应用广泛的精细化工产品,可以由甲基三乙基碳酸氢铵经电解制得。以三乙胺和碳酸二甲酯为原料,采用两步法合成甲基三乙基氢氧化铵的原料甲基三乙基碳酸氢铵。从物料比、反应温度、氮气初始压力、反应时间、水解温度5个方面对合成工艺进行了优化。结果表明,在n(碳酸二甲酯)∶n(三乙胺)=1.5∶1、反应温度150℃、反应压力1.5 MPa、反应时间6 h,中间体甲基三乙基铵碳酸单甲酯的收率达90%。水解温度为70℃时,标题化合物的收率接近100%。     

四甲基氢氧化铵的制备与检测

介绍了四甲基氢氧化铵的制备与检测方法.四甲基氢氧化铵的制备主要采用电解的方法,电解的原料有四甲基氯化铵和四甲基碳酸氢铵,两种原料在制备四甲基氢氧化铵的过程中各有优缺点,提纯原料的过程中也采用了不同的理念.四甲基氢氧化铵的检测项目主要是根据四甲基氢氧化铵的应用场合并结合具体的应用工艺,对所确定的检测指标及确认的数值范围进...     

浅议影响离子膜电解槽电流效率的因素

保持最佳的离子膜电解工艺操作条件是离子膜电解槽的操作关键,它能使离子膜长期稳定地保持较高的电流效率和较低的槽电压,进而稳定直流电耗,延长离子膜的使用寿命。本文详细分析了影响离子膜电解槽电流效率的因素,认为电解槽在运行过程中,要保持高的电流效率应做到:高质量的入槽盐水;适宜的阴极液浓度、阳极液浓度和适宜的电流密度;严格控制阳极液PH值;保持适宜的电解槽温度、电解液流量和稳定的高质量的无离子水供应。     

双极膜成对电合成L-磺基丙氨酸和L-半胱氨酸

利用自制的CuTsPc-SA/CuTAPc-CS双极膜（CuTsPc：四磺酸基铜酞菁;SA：海藻酸钠;CuTAPc：四氨基铜酞菁;CS：壳聚糖）作为电解槽隔膜,成对电解L-胱氨酸合成L-磺基丙氨酸和L-半胱氨酸,提高了电流效率,降低了生产成本。研究表明,电解时电流密度以35mA/cm^2为宜,阴极室L-胱氨酸的初始浓度以0.65mol/L为宜。当氢溴酸浓度为3 mol/L时,阳极室电流效率达到最大值,为85.1%。     

Dispersion and rheological properties of concentrated silicon aqueous suspension

This work focuses on the optimization of the rheological properties of silicon suspensions by changing the concentration of a dispersant and the pH value of the dispersing medium. The zeta potential and rheological properties of silicon suspensions as a function of tetramethyl ammonium hydroxide (TMAH) concentration were carried out. The results show that the isoelectric point of the silicon particles was at pH 1.6. A silicon suspension with 46 vol.% particles displayed a minimum viscosity at pH 9.6. The results also show that TMAH is an efficient dispersant by enhancing the absolute value of the zeta potential of silicon particles. The optimum dosage of the dispersant was 0.4 wt.% of silicon particles.     

Hybrid treatment of tetramethyl ammonium Hydroxide occurring from Electronic materials industry

TMAH (tetramethyl ammonium hydroxide) originating from etching and photo-developing processes was treated with Fenton oxidation followed by an activated sludge. Additionally, a Microtox test was performed to address any potential toxicity of TMAH against mixed cultures of microorganisms in the activated sludge. The Microtox test revealed that toxicity of TMAH againstPhotobacterium phosphoreum was highly effective showing 5% of EC₅₀, but its toxicity was completely dissipated showing 100% of EC₅₀ being recovered after being treated with Fenton reagents. BOD₅ test showed that acclimated cultures to TMAH could readily decompose TMAH in an order of magnitude higher than that of not-acclimated culture. Feasibility tests showed that TMAH was readily biodegraded after being oxidized by the Fenton process, while TMAH fed directly into the activated sludge was laggardly decomposed during longer adaptation period. In the presence of acetic acid, activity of acclimated mixed cultures to TMAH was considerably reduced by dominant presence of predators competitively utilizing acetic acid.     

燃料电池用碱性阴离子交换膜的研究进展

碱性阴离子交换膜(AAEM)是碱性阴离子交换膜燃料电池(AAEMFC)的核心部件,起到阻隔阴阳两极和传导OH-的双重作用,其性能好坏直接影响到AAEMFC的性能和使用寿命。从膜的结构和制备方法分类,综述了碱性阴离子交换膜燃料电池用有机-无机杂化膜、掺杂型膜及均相膜的特性和研究现状。     

分散剂用量对碳化硅浆料流变性能的影响

使用四甲基氢氧化铵(TMAH)作为分散剂,研究了分散剂用量对SiC浆料流变性能的影响,并分析了其原因。结果表明：TMAH能够显著提高SiC粉体的zeta电位,降低浆料粘度,从而显著优化浆料的流变性能。在pH为10左右,加入质量分数为0．3％和o．6％NTMAH后zeta电位分别提高了11.7mV和21mV。实验中,在不同体积分数SiC浆料中,加入0．6%TMAH时能够达到最优性能,浆料粘度都达到最低。过量的分散剂则会增加浆料中的离子浓度而导致双电层厚度减小,从而恶化浆料的流变性。     

Preparation and use of a mesoporous silicate material for the removal of tetramethyl ammonium hydroxide (TMAH) from aqueous solution

A cubic mesoporous silicate (CMS) was prepared, characterised, and assessed as an adsorbent for tetramethyl ammonium hydroxide (TMAH) from aqueous solution. The adsorption process was studied as a function of temperature and time. Sorption closely followed the Langmuir model. The adsorption of TMAH on CMS was endothermic and kinetic studies suggest that the overall rate of adsorption was pseudo‐second‐order. Pore diffusion effects contribute to limiting the overall rate of adsorption while at lower initial TMAH concentrations, film diffusion becomes more important. Desorption studies were carried out using water and methanol. Methanol was the superior desorbing agent. © 2001 Society of Chemical Industry     

年产10万吨烧碱车间化盐工段模拟工艺设计

离子膜法制碱是当今氯碱工业中崛起的新技术,膜电解生产的氢氧化钠浓度可达30%-50%(质量)。此外,离子膜电解制碱还有投资省、生产成本低、能耗低、无污染、氢氧化钠质量好等优点。因此在国内外无论是新建、改造和扩建生产装置都会首先考虑这一技术。生产满足离子膜电解槽运行要求的精制盐水必须进行精制操作除去盐水中的大量杂质,本设计按照经济合理、技术先进、系统最优、工艺可靠的原则完成。包括化盐工段的工艺方案(一次精制盐水、二次精制盐水)、工艺流程图以及初步物料衡算与经济预算。     

Effects of interface hydrophilicity and metallic compounds on water-splitting efficiency in bipolar membranes

Bipolar membranes (BPMs) were prepared by using commercial ion exchange membranes and hydrophilic polymer as a binder to investigate the effects of the interface hydrophilicity on water-splitting capacity. In this study, polyHEMA/MPD cross-linked with TMC was used as a binding material to enhance the BPM interface hydrophilicity. The enhanced hydrophilicity of the BPM interface accelerated the water-splitting reaction because the hydrophilic polymer layer increases the water activity by attracting water from the ion exchange layers to the space charge region. In addition, a mechanism of the metal catalytic reaction was proposed. Metal species were immobilized in the BPM in a hydroxide form and possibly react with water molecules and the quaternary ammonium groups reversibly. It was also observed that metal species immobilized in the membrane improved the water-splitting efficiency by increment of the membrane wetness and enhancement of the membrane conductivity, with an apparent optimum metal concentration for the water-splitting reaction.