【作者】 魏晓丽；

【导师】 李占双；

【作者基本信息】 哈尔滨工程大学 ， 应用化学， 2007， 硕士

【摘要】 甲基萘（MN）和1，2，4，5-四甲苯（TeMB）转移烷基化合成2，6-二甲基萘（2，6-DMN）是最具研究价值和开发潜力的方法之一。在转移烷基化反应中，由于产物的复杂性，研制出新型高效的环境友好酸催化剂是高选择性地合成2，6-DMN的关键。本文合成了不同酸强度的烷基咪唑、烷基吡啶和季铵盐系列氯铝酸盐类离子液体（分别表示为[C_nmim]X-xAlCl₃、[C_nPy]X-xAlCl₃和Et₃NHCl-xAlCl₃），分别用吡啶和乙腈吸附的FT-IR、²⁷Al NMR对离子液体的酸性和存在形式进行了表征，确定离子液体分别具有Lewis酸和Br（?）nsted酸中心，离子液体的酸性和阴离子物种的存在形式主要由无水三氯化铝在离子液体中的摩尔分数决定，阳离子的结构对离子液体的酸性也有一定程度的影响。本文主要研究了以下内容：分别考察了不同阳离子结构的氯铝酸盐类离子液体的酸强度、反应温度、反应时间等因素对MN和TeMB转移烷基化的催化反应活性和2，6-DMN选择性的影响，优化得到适宜的反应条件为：以[C_nmim]X-xAlCl₃和[C_nPy]X-xAlCl₃为催化剂时，AlCl₃的摩尔分数x=0.71，2-MN和TeMB摩尔比为1∶1，离子液体用量为32wt％，反应温度为20℃，反应时间为8h；以Et₃NHCl-xAlCl₃为催化剂时，反应时间缩短到6h。在相同反应条件下，Et₃NHCl-xAlCl₃作用下的2-MN具有最高催化活性，2-MN的转化率和2，6-DMN的选择性分别达到48.7％和48.1％，但2，6-DMN/2，7-DMN偏低，只达到2.3；以[C₄Py]Cl-xAlCl₃离子液体为催化剂时，产物中2，6-DMN具有最高的选择性和2，6-DMN/2，7-DMN，分别为80.5％和4.1。[C₄mim]Cl-xAlCl₃的催化反应活性和2，6-DMN的选择性介于Et₃NHCl-xAlCl₃和[C₄Py]Cl-xAlCl₃之间。在以上离子液体催化下以混合MN为原料的转移烷基化反应仍然可以得到高选择性的2，6-DMN。考察了离子液体的循环使用情况，分析确定了离子液体的失活原因，认为反应体系中的微量水使离子液体水解是造成离子液体失活的主要原因。提出了氯铝酸盐类离子液体催化甲基萘和1，2，4，5-四甲苯转移烷基化的反应机理，认为离子液体催化是质子酸催化历程，产生适宜活性和空间障碍大的过渡态C⁺是提高2，6-DMN选择性的主要原因。更多还原

【Abstract】 Preparation of 2,6-dimethylnaphthalene（2,6-DMN） through transalkylation reaction of methylnaphthalene（MN） and 1,2,4,5-tetramethylbenzene（TeMB） is one of methods with excellent exploitation value and potentiality. Searching high effectively and environmental benign catalysts for synthesis of 2,6-DMN with high selectivity in the transalkylation reaction is the key technology due to products complexity.In this paper, Alkylimidazolium Chlorine-aluminate Ionic Liquids, Alkylpyridinium Chlorine-aluminate Ionic Liquids, triethylamine hydrochlorine-aluminium（Ⅲ） Chloride Ionic Liquids（denoted:[C_nmim]X-xAlCl₃, [C_nPy]X-xAlCl₃ and Et₃NHCl-xAlCl₃, respectively） were preparation. Forms of the existence and acidic properties of ionic liquids were characterized by Py-IR, acetonitrile-IR and ²⁷Al NMR. The results showed that ionic liquids had both Lewis and Bronsted acid sites; the molar fraction of AlCl₃ determined the acidic properties and forms of inorganic anions species of ionic liquids, on the other hand the structure of cation have affect on the acidic properties to some extent. The main content of this paper as follows:The acidic strength, reaction temperature, reaction time of Chlorine-aluminate Ionic Liquids with different structure of cation on the activity of transalkylation of MN with TeMB and the selectivity of 2,6-DMN were studied. The optimum reaction condition was obtained: the molar fraction of AlCl₃ is 0.71, molar ratio of 2-MN and TeMB is 1, the amount of ionic liquid is 32wt%, reaction temperature is 20℃and reaction time is 8h using [C_nmim]X-xAlCl₃ and [C_nPy]X-xAlCl₃ as catalysts; the optimum reaction time is shortened 6h using Et₃NHCl-xAlCl₃ as catalyst. Under the same reaction condition, 48.7% conversion of 2-MN, 48.1% selectivity of 2,6-DMN but lower ratio of 2,6-DMN to 2,7-DMN（2.3） were obtained when the Et₃NHCl-xAlCl₃ used as catalyst. On contrast, the highest selectivity of 2,6-DMN and 2,6-DMN /2,7-DMN（80.5% and 4.1, respectively） were obtained when the[C₄Py]Cl-xAlCl₃ used as catalyst. The catalysts activity and selectivity of 2,6-DMN of [C₄mim]Cl-xAlCl₃ were between two above catalysts. The high selectivity of 2,6-DMN also can be obtained by transalkylation reaction using a mixture of MNs.Under the optimal reaction condition, the deactivation of multiple reaction were researched, then we analysed the causes for ionic liquids deactivation. It was found that moisture in the system of reaction is main reason that lead to deactivation of ionic liquids.The reaction mechanism of transalkylation reaction of methylnaphthalene and 1,2,4,5-tetramethylbenzene catalyzed by chlorine-aluminate ionic liquids has been proposed. It was found that the course of ionic liquids catalytic reaction is proton acid catalytic reaction as well as the main reason of high selectivity of 2,6-DMN is the formation of transition state of C⁺ with the feasible acidic properties and steric hindrance.更多还原