河北工业大学硕士学位论文环己酮氨肟化及贝克曼重排反应研究姓名:姬亚宁申请学位级别:硕士专业:化学工艺指导教师:程庆彦20100501河北工业大学硕士学位论文i 环己酮氨肟化及贝克曼重排反应研究摘要环己酮氨肟化一步法合成己内酰胺是重要的新型绿色化学反应。
柱撑蒙脱土是一种人工合成的新颖催化材料,在催化领域有较广阔的应用前景。
本文研究了钛柱撑蒙脱土、硅钛柱撑蒙脱土和掺杂稀土金属的硅钛柱撑蒙脱土的制备,对其进行了物化性质表征,在环己酮氨肟化反应中测试了其催化性能;以P2O5为催化剂,使用迅速简单的微波技术,通过液相贝克曼重排法高收率的制得己内酰胺;将这两种工艺过程集成,研究环己酮氨氧化一锅合成己内酰胺的反应。
采用溶胶凝胶法制备钛柱撑剂、硅钛柱撑剂及掺杂稀土金属的硅钛柱撑剂,离子交换法制备柱撑型蒙脱土催化剂,进行了XRD、FT-IR、TG-DSC、SEM-EDX、BET等表征分析,通过环己酮氨肟化反应进行催化性能评价。
结果表明,Ti:MMT为6mmol:1g,柱撑剂的OH-:H+摩尔比为3:1、Si:Ti摩尔比为1:2、水热法交联、450℃焙烧,硅钛柱撑蒙脱土的层间距由原钠基蒙脱土的0.98nm增大到1.02nm,比表面积由原钠基蒙脱土的35.9m2/g变为138.3m2/g,热稳定性较好,当温度升到900℃时,失重率为2.27%。
铕掺杂的硅钛柱撑蒙脱土有较好的荧光性能。
活性评价结果表明:反应时间为5h,反应温度为75℃,催化剂Eu3+掺杂硅钛柱撑蒙脱土用量为0.5g,n(环己酮):n(H2O2):n(NH3)为1.0: 1.5:2.0,环己酮肟的收率为24.93%。
以P2O5为催化剂,研究了环己酮肟液相贝克曼重排反应,发现微波辐射对此反应有促进作用,考察了重排反应中的影响因素,优化的工艺条件为:催化剂P2O5的质量分数为14%,10mL N,N-二甲基甲酰胺为反应介质,1.153g环己酮肟,微波辐射强度为280W,辐射时间5min,环己酮肟的转化率达到99.89%,己内酰胺的收率达到了95.48%、选择性为97.45%。
在环己酮氨肟化反应与贝克曼重排反应集成中,环己酮肟化反应步骤中水、环己酮和催化剂对液相贝克曼重排反应的影响较大,使得一锅法合成己内酰胺过程较为复杂。
关键词:环己酮,氨肟化,柱撑蒙脱土,P2O5,液相贝克曼重排,微波促进环己酮氨肟化及贝克曼重排反应研究iiSTUDY ON THE REACTION OF CYCLOHEXANONE AMMOXIDATION AND B ECKMANN REARRANGEMENTABSTRACTThe one-step synthesis ofε-caprolactam(CPL)from cyclohexanone ammoxidation is one ofthe novel routes in green chemistry.The pillared montmorillonite is a novel synthetic catalytic material,which have application prospect in the catalytic field.In this thesis,titanium pillared montmorillonite,silicon titanium pillared montmorillonite and earth metal doped silicon-titanium pillared montmorillonite were synthesized and their physicochemical properties were characterized thoroughly,the catalytic performance for cyclohexanone ammoximation was investigated.ε-caprolactam was synthesized by microwave assisted to improve the catalytic performance of P2O5catalyst towards cyclohexanone oxime liquid phase Beckmann rearrang-ement.Then,the one-pot synthesis ofε-caprolactam from cyclohexanone ammoxidation was studied.Titanium pillared-reagent,silicon-titanium pillared-reagent and rare metal doped silicon–titanium pillared-reagent were prepared by sol-gel method,and pillared montmorillonite catalysts were prepared by ion exchange method.The prepared pillared montmorillonite were determined by XRD,FT-IR,TG-DSC,SEM-EDX and BET.The catalytic performance of the catalysts for cyclohexanone ammoximation was investigated.The results show that when Ti: MMT ratio is6:1(mmol/g),OH-:H+for pillared-reagent molar ratio is3:1,Si:Ti molar ratio is 1:2,hydrothermal cross-linking method,calcinations temperature is450℃,the spacing of layers of silicon-titanium pillared montmorillonite increase from0.98nm of the sodium montmori-llomite to1.02nm,the specific surface area of silicon-titanium pillared montmorillonite increase from35.9m2/g of the sodium montmorillomite to138.3m2/g.The silicon-titanium pillared montmorillonite show good thermal stability,when the temperature arrives at about900℃,the weight loss is only2.27%.Eu3+doped silicon–titanium pillared montmorillonite show good fluorescence properties.The result of activity evaluation for cyclohexanone ammoximation show that when reaction time is5h,the reaction temperature is75℃,the amount of catalyst Eu3+ doped silicon–titanium pillared montmorillonite is0.5g,n(cyclohexanone):n(H2O2):n(NH3) is1.0:1.5:2.0,the yield of cyclohexanone oxime is24.93%.The catalytic performance of P2O5catalyst towards cyclohexanone oxime liquid phase河北工业大学硕士学位论文Beckmann rearrangement was studied.The result show that microwave assisted synthesis could improve the catalytic performance of P2O5,the yield and selectivity of CPL reached95.48%and 97.45%,respectively,under the optimum reaction conditions of the amount of catalyst P2O5of 14%,10mL DMF as reaction medium,cyclohexanone oxime of1.153g,microwave radiation intensity of280W,microwave radiation time of5min.The one-pot synthesis ofε-caprolactam from cyclohexanone ammoxidation is complex,the water,cyclohexanone and catalyst which come from the reaction of cyclohexanone ammoxima-tion have obvious influence on the reaction of Beckmann rearrangement.K EY WORDS:cyclohexanone,ammoximation,pillared montmorillonite,P2O5,liquid phase Beckmann rearrangement,microwave promotediii河北工业大学硕士学位论文1第一章文献综述随着工业上对尼龙-6需求量的不断增加,开发由环己酮合成ε-己内酰胺环境友好的工艺具有十分重要的意义。
目前,在ε-己内酰胺大规模的工业生产中,主要采用两种两步法工艺。
两种工艺均以环己酮为原料,第一种工艺采用硫酸羟胺氧化环己酮生成中间产物环己酮肟,反应过程中需要NH3来中和硫酸,使用发烟硫酸催化环己酮肟重排生成己内酰胺;第二种工艺采用对环境较为友好的H2O2为氧化剂,钛硅分子筛TS-1催化剂催化环己酮氨氧化,也使用发烟硫酸催化环己酮肟重排生成己内酰胺。
这两种工艺均使用高污染的试剂及副产大量低值硫酸铵,对环境不友好[1]。