炭磺酸结构和酸性官能团的稳定性研究
发布时间：2018-12-19 11:34
【摘要】：生物质固体炭磺酸自2004年出现开始已然成为固体酸催化剂中的研究热点。炭磺酸的催化稳定性主要依赖于其炭骨架结构以及活性中心的稳定性。提高炭磺酸的机械性能,研究活性中心稳定性降低的原因可以为进一步改进催化剂稳定性提供新方法,为实现炭磺酸的工业化生产提供基础研究。以废弃樟树枝原料制备了樟木炭磺酸,并通过官能团屏蔽的方法对其酸性官能团在环氧环己烷的甲醇解反应中的作用进行了探究。炭磺酸上磺酸基团是本反应的主要催化活性中心,羧酸官能团具有较弱的催化活性,而酚羟基没有活性,但酚羟基的存在能提高炭磺酸的催化性能。根据反应动力学结果,弱酸性官能团对反应的促进作用是通过促进反应底物在催化剂表面的吸、脱附过程来实现的。以竹屑为原料制备了竹炭磺酸,分别以环己酮缩乙二醇的合成和环氧环己烷的甲醇解考察了竹炭磺酸在有水参与的反应体系和无水反应体系中催化活性降低的原因。炭磺酸催化活性降低是因为其活性中心磺酸官能团的丧失:在合成环己酮缩乙二醇的反应中磺酸根水解和成酯是磺酸量下降的原因,在环氧环己烷的甲醇解反应中则主要是因为磺酸根的成酯反应。采用氢离子交换和再次磺化的方法可恢复催化剂活性。以竹材加工过程中产生的废弃竹块为原料,通过减压炭化-甲醛处理-磺化的方法制备了抗磨损强度较大的炭磺酸催化剂。建立了磨损强度测试的方法,对甲醛处理提高竹炭磺酸磨损强度的制备条件进行了优化。磨损强度相比于未经甲醛处理制备的炭磺酸的磨损强度得到了很大的提高。炭化产物与甲醛溶液和40 wt%硫酸比(m:V:V)为4:20:1,处理温度40℃,处理时间8 h,竹炭磺酸的磨损率可降低至4.03%。而同条件下未用甲醛处理的竹炭磺酸磨损率为25.28%。
[Abstract]:Biomass solid carbon sulfonic acid has been a hot research topic in solid acid catalysts since its appearance in 2004. The catalytic stability of carbon sulfonic acid mainly depends on the structure of carbon skeleton and the stability of active center. Improving the mechanical properties of carbon sulfonic acid and studying the reason of decreasing the stability of active center can provide a new method for further improving the stability of catalyst and provide basic research for realizing the industrial production of carbon sulfonic acid. Cinnamomum camphora charcoal sulfonic acid was prepared from the waste camphor branch and the role of acid functional group in methanol hydrolysis of cyclohexane was investigated by functional group shielding method. The sulfonic group on the carbon sulfonic acid group is the main catalytic active center in this reaction. The carboxylic acid functional group has weak catalytic activity, but the phenolic hydroxyl group has no activity. However, the presence of phenol hydroxyl group can improve the catalytic activity of carbon sulfonic acid. According to the results of reaction kinetics, the promotion of weakly acidic functional groups to the reaction is achieved by promoting the adsorption and desorption of the substrate on the surface of the catalyst. Bamboo charcoal sulfonic acid was prepared from bamboo chips. The reasons for the decrease of catalytic activity of bamboo charcoal sulfonic acid in aqueous and anhydrous reaction systems were investigated by synthesis of cyclohexanone glycol and methanol hydrolysis of cyclohexane respectively. The decrease in catalytic activity of carbon sulfonic acid is due to the loss of the sulfonic functional group of its active center: the hydrolysis and esterification of sulfonic acid in the synthesis of cyclohexanone ethylene glycol are the reasons for the decrease in sulfonic acid content. The methanol hydrolysis of cyclohexane is mainly due to the esterification of sulfonic acid. The catalyst activity can be restored by hydrogen ion exchange and re-sulfonation. The carbon sulfonic acid catalysts with high wear resistance were prepared by decompression carbonization formaldehyde treatment and sulfonation from the waste bamboo blocks produced in the process of bamboo processing. The wear strength test method was established and the preparation conditions of formaldehyde treatment to improve the wear strength of bamboo charcoal sulfonic acid were optimized. Compared with the carbon sulfonic acid prepared without formaldehyde treatment, the wear strength of carbon sulfonic acid was greatly improved. The ratio of carbonized product to formaldehyde solution and 40 wt% sulfuric acid (m:V:V) was 4: 20: 1, treatment temperature was 40 鈩，
本文编号：2386865
[Abstract]:Biomass solid carbon sulfonic acid has been a hot research topic in solid acid catalysts since its appearance in 2004. The catalytic stability of carbon sulfonic acid mainly depends on the structure of carbon skeleton and the stability of active center. Improving the mechanical properties of carbon sulfonic acid and studying the reason of decreasing the stability of active center can provide a new method for further improving the stability of catalyst and provide basic research for realizing the industrial production of carbon sulfonic acid. Cinnamomum camphora charcoal sulfonic acid was prepared from the waste camphor branch and the role of acid functional group in methanol hydrolysis of cyclohexane was investigated by functional group shielding method. The sulfonic group on the carbon sulfonic acid group is the main catalytic active center in this reaction. The carboxylic acid functional group has weak catalytic activity, but the phenolic hydroxyl group has no activity. However, the presence of phenol hydroxyl group can improve the catalytic activity of carbon sulfonic acid. According to the results of reaction kinetics, the promotion of weakly acidic functional groups to the reaction is achieved by promoting the adsorption and desorption of the substrate on the surface of the catalyst. Bamboo charcoal sulfonic acid was prepared from bamboo chips. The reasons for the decrease of catalytic activity of bamboo charcoal sulfonic acid in aqueous and anhydrous reaction systems were investigated by synthesis of cyclohexanone glycol and methanol hydrolysis of cyclohexane respectively. The decrease in catalytic activity of carbon sulfonic acid is due to the loss of the sulfonic functional group of its active center: the hydrolysis and esterification of sulfonic acid in the synthesis of cyclohexanone ethylene glycol are the reasons for the decrease in sulfonic acid content. The methanol hydrolysis of cyclohexane is mainly due to the esterification of sulfonic acid. The catalyst activity can be restored by hydrogen ion exchange and re-sulfonation. The carbon sulfonic acid catalysts with high wear resistance were prepared by decompression carbonization formaldehyde treatment and sulfonation from the waste bamboo blocks produced in the process of bamboo processing. The wear strength test method was established and the preparation conditions of formaldehyde treatment to improve the wear strength of bamboo charcoal sulfonic acid were optimized. Compared with the carbon sulfonic acid prepared without formaldehyde treatment, the wear strength of carbon sulfonic acid was greatly improved. The ratio of carbonized product to formaldehyde solution and 40 wt% sulfuric acid (m:V:V) was 4: 20: 1, treatment temperature was 40 鈩，
本文编号：2386865
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