TS-1微球的制备及其甲基氯丙烯环氧化催化性能的研究
发布时间：2018-10-09 07:23
【摘要】：以钛硅分子筛为催化剂,催化甲基氯丙烯与双氧水直接环氧化生产甲基环氧氯丙烷的方法是一种工艺流程短,对环境无污染的绿色化学过程。本文开展合成高活性、易分离、适合淤浆床反应器的整体式TS-1微球分子筛,及其催化甲基氯丙烯环氧化生成甲基环氧氯丙烷性能的研究。探讨TS-1微球的形成过程和液相氧化催化活性,进一步研究其催化甲基氯丙烯生成环氧甲基氯丙烷反应的最优条件和再生过程。我们在常规合成TS-1的体系中加入三嵌段共聚物F127,通过分步晶化后实现TS-1纳米粒子的聚集成球。通过调节F127加入量控制微球分子筛的大小,进一步添加微量CTAB表面活性剂使得微球形貌更加均匀。在物料摩尔比为TEOS:TPAOH:TBOT:H2O:F127:CTAB= 1:0.18:0.033:13.2:0.0027:0.0032时,合成的TS-1分子筛微球直径为15 μm左右,形貌均匀。通过氮气吸脱附表征,发现TS-1微球与常规TS-1相比,比表面积增加,并形成了晶粒间介孔。在淤浆床中以TS-1微球催化H2O2氧化甲基氯丙烯生成甲基环氧氯丙烷,从工业化角度,考察了各个因素对双氧水转换率、甲基环氧氯丙烷选择性和催化剂使用寿命的影响。在最佳反应条件,即反应温度从313 K间断升温到343 K、MAC/H2O2摩尔比例为3、TBA/MAC质量比为2、TS-1微球催化剂浓度为35 g L-1、NH3·H2O浓度为17 ppm、滞留时间为4 h时,催化剂寿命可以达到257 h,且此过程中甲基环氧氯丙烷选择性高于95%,双氧水利用率高于97%。在反应过程中TS-1微球分子筛显示出催化活性高和容易固液分离的特点。对TS-1微球催化H2O2氧化甲基氯丙烯生成甲基环氧氯丙烷的失活机理进行了研究,发现失活主要是由于分子筛孔道内积炭所致,伴随着长时间反应过程中分子筛内部分骨架Ti的流失也是催化剂失活的原因。双氧水洗涤与高温焙烧都是催化剂再生的有效方法,随着再生次数的增加,催化剂活性逐渐降低。
[Abstract]:The method of direct epoxidation of methoxypropylene and hydrogen peroxide to produce methyl epichlorohydrin using titanium-silicon molecular sieve as catalyst is a green chemical process with short technological process and no pollution to the environment. In this paper, the synthesis of monolithic TS-1 microsphere molecular sieve with high activity, easy separation and suitable for slurry reactor, and its catalytic properties of epoxidation of methyl chloropropene to methyl epichlorohydrin were studied. The formation process and the catalytic activity of liquid phase oxidation of TS-1 microspheres were discussed. The optimum conditions and regeneration process for the reaction of methylene to epichlorohydrin were studied. A triblock copolymer F127 was added to the system of conventional synthesis of TS-1, and the TS-1 nanoparticles were assembled into spheres by stepwise crystallization. By adjusting the amount of F127 to control the size of the microsphere molecular sieve, further adding a small amount of CTAB surfactants to make the morphology of the microspheres more uniform. At the molar ratio of TEOS:TPAOH:TBOT:H2O:F127:CTAB= 1: 0.18: 0.033: 13.2: 0.0027: 0.0032, the synthesized TS-1 molecular sieve microspheres are about 15 渭 m in diameter and uniform in morphology. It was found that the specific surface area of TS-1 microspheres was higher than that of conventional TS-1, and mesoporous grains formed. TS-1 microspheres were used to catalyze the oxidation of H2O2 to methoxychloropropane in slurry bed. From the point of view of industrialization, the effects of various factors on hydrogen peroxide conversion rate, selectivity of methyl epichlorohydrin and service life of catalyst were investigated. The optimum reaction conditions were as follows: the reaction temperature was increased from 313K to 343K / H _ 2O _ 2 molar ratio of 3o TBA / MAC was 2% TS-1 catalyst concentration was 35 g / L ~ (-1) NH _ 3H _ 2O concentration was 17 ppm, and the retention time was 4 h, when the catalyst concentration was 35 g / L ~ (-1) NH _ 3H _ 2O. The catalyst has a lifetime of 257 h, and the selectivity of methyl epichlorohydrin is higher than 95%, and the hydrogen peroxide utilization ratio is higher than 97%. TS-1 microsphere molecular sieves showed high catalytic activity and easy solid-liquid separation during the reaction. The deactivation mechanism of H2O2 oxidation of methoxypropylene to methoxychloropropane catalyzed by TS-1 microspheres was studied. It was found that the deactivation was mainly caused by carbon deposition in the pore channels of molecular sieve. The loss of part of skeleton Ti in molecular sieve was also the reason of catalyst deactivation. Hydrogen peroxide washing and high temperature roasting are effective methods for catalyst regeneration. With the increase of regeneration times, the activity of catalyst decreases gradually.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ223.26
本文编号：2258464
[Abstract]:The method of direct epoxidation of methoxypropylene and hydrogen peroxide to produce methyl epichlorohydrin using titanium-silicon molecular sieve as catalyst is a green chemical process with short technological process and no pollution to the environment. In this paper, the synthesis of monolithic TS-1 microsphere molecular sieve with high activity, easy separation and suitable for slurry reactor, and its catalytic properties of epoxidation of methyl chloropropene to methyl epichlorohydrin were studied. The formation process and the catalytic activity of liquid phase oxidation of TS-1 microspheres were discussed. The optimum conditions and regeneration process for the reaction of methylene to epichlorohydrin were studied. A triblock copolymer F127 was added to the system of conventional synthesis of TS-1, and the TS-1 nanoparticles were assembled into spheres by stepwise crystallization. By adjusting the amount of F127 to control the size of the microsphere molecular sieve, further adding a small amount of CTAB surfactants to make the morphology of the microspheres more uniform. At the molar ratio of TEOS:TPAOH:TBOT:H2O:F127:CTAB= 1: 0.18: 0.033: 13.2: 0.0027: 0.0032, the synthesized TS-1 molecular sieve microspheres are about 15 渭 m in diameter and uniform in morphology. It was found that the specific surface area of TS-1 microspheres was higher than that of conventional TS-1, and mesoporous grains formed. TS-1 microspheres were used to catalyze the oxidation of H2O2 to methoxychloropropane in slurry bed. From the point of view of industrialization, the effects of various factors on hydrogen peroxide conversion rate, selectivity of methyl epichlorohydrin and service life of catalyst were investigated. The optimum reaction conditions were as follows: the reaction temperature was increased from 313K to 343K / H _ 2O _ 2 molar ratio of 3o TBA / MAC was 2% TS-1 catalyst concentration was 35 g / L ~ (-1) NH _ 3H _ 2O concentration was 17 ppm, and the retention time was 4 h, when the catalyst concentration was 35 g / L ~ (-1) NH _ 3H _ 2O. The catalyst has a lifetime of 257 h, and the selectivity of methyl epichlorohydrin is higher than 95%, and the hydrogen peroxide utilization ratio is higher than 97%. TS-1 microsphere molecular sieves showed high catalytic activity and easy solid-liquid separation during the reaction. The deactivation mechanism of H2O2 oxidation of methoxypropylene to methoxychloropropane catalyzed by TS-1 microspheres was studied. It was found that the deactivation was mainly caused by carbon deposition in the pore channels of molecular sieve. The loss of part of skeleton Ti in molecular sieve was also the reason of catalyst deactivation. Hydrogen peroxide washing and high temperature roasting are effective methods for catalyst regeneration. With the increase of regeneration times, the activity of catalyst decreases gradually.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ223.26
【参考文献】
相关博士学位论文 前1条
1 张海娇;TS-1分子筛合成新方法及其催化性能的研究[D];华东师范大学;2007年
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