Development of highly effective catalyst for Beckmann rearrangement

贝克曼重排高效催化剂的开发

• 批准号: 06453101
• 负责人: YASHIMA Tatsuaki
• 金额: $ 4.54万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06453101/
• 关键词: Cyclohexanone oxime; Beckmann rearrangement; epsilon-caprolactam; Zeolite; Silicalite; Ferrierite; Silica gel; Hydroxyl group; シリカゲル; ゼオライト触媒; 固体酸性

Vapor phase Beckmann rearrangement of cyclohexanone oxime was carried out with continuous flow system. Various zeolites were examined to clarify the effect of zeolite pore on the selectivity. High selectivity to epsilon-caprolactam was obtained on Ca-A and borosilicate with template molecules remaining in the pore. The pore sizes of these zeolites are too small for the molecules of cyclohexanone oxime to enter. Therefore, it was revealed that the reaction to produce bulky epsilon-caprolactam proceeds selectively on the external surface of these zeolite and that the side reaction to produce smaller molecules dominates inside the pore. Catalytic performances of various oxides were examined to clarify the nature of the active site. Strong acid zeolites, H-ZSM-5, H-mordenite, H-Y,etc., gave low selectivity to epsilon-caprolactam (30-60 mol%) mainly because of the formation of by-products having high boiling point. Basic zeolites, K-ZSM-5, K-ferrierite, etc., also exhibited the low selectiv … More ity (30-60 mol%). Amorphous oxides, gamma-alumina, titania, zirconia, etc., gave the selectivity lower than 40 mol%. Higher selectivity (>80 mol%) was obtained when crystalline oxides, such as H-ferrierite, Ca-A zeolite, H-SAPO-5 and silicalite-1, were used. These catalysts do not have strong acid and base sites, which also results in the higher stability due to much less accumulation of the by-products. These results indicate that neutral and weakly acidic hydroxyl groups are also active for the formation of epsilon-caprolactam and that these hydroxyls are more effective for the selective and stable formation of epsilon-caprolactam than strong acid or base sites. However, silica gel, which has also neutral hydroxyl groups, exhibited low selectivity. Treatment with aluminum chloride on silica gel, which eliminated part of surface hydroxyls, enhanced the selectivity. The surface concentration of neutral hydroxyl group may have an important role on the selective formation of epsilon-caprolactam. Less

采用连续流动体系进行了环己酮肟的气相Beckmann重排反应。考察了各种沸石分子筛的孔结构对选择性的影响。在模板分子滞留在孔内的情况下，Ca-A和硼硅酸盐催化剂对己内酰胺有较高的选择性。这些沸石的孔径太小，环己酮肟分子无法进入。结果表明，生成大体积己内酰胺的反应是选择性地在沸石的外表面进行的，而生成小分子的副反应主要发生在孔内。考察了各种氧化物的催化性能，以明确活性中心的性质。强酸性分子筛H-ZSM-5、H-丝光沸石、H-Y等对己内酰胺选择性较低，主要原因是生成了高沸点的副产物。K-ZSM-5、K-铁氧体等碱性沸石也表现出较低的选择性…更多的量(30-60摩尔%)。无定形氧化物，如γ-氧化铝、二氧化钛、氧化锆等，选择性低于40mol%。当使用H-铁氧体、Ca-A沸石、H-SAPO-5和Silicalite-1等晶态氧化物时，可获得较高的选择性(&gt；80mol%)。这些催化剂没有很强的酸碱中心，这也导致了更高的稳定性，因为副产物的积累要少得多。这些结果表明，中性和弱酸性羟基对己内酰胺的生成也具有活性，并且这些羟基对己内酰胺的选择性和稳定性的形成比强酸或强碱中心更有效。然而，同样具有中性羟基的硅胶表现出较低的选择性。用三氯化铝在硅胶上处理，消除了部分表面羟基，提高了选择性。中性羟基的表面浓度可能对己内酰胺的选择性形成起重要作用。较少

项目成果

Tatsuaki Yashima: "Beckmann rearrangement of cyclohexanone oxime on the external surface of zeolite crystals." Stud.Surf.Sci.Catal.84. 1897-1904 (1994)

Tatsuaki Yashima：“环己酮肟在沸石晶体外表面的贝克曼重排。”

Tatsuaki Yashima: "Beckmann rearrangement of cyclohexanone oxime on the external surface of zeolite crystals" Stud.Surf.Sci.Catal.84. 1897-1904 (1994)

Tatsuaki Yashima：“环己酮肟在沸石晶体外表面上的贝克曼重排”Stud.Surf.Sci.Catal.84。

T. Yashima et al.: "Beckmann rearrangement of cyclohexanone oxime on the external surface of zeolite crystals" Stud. Surf. Sci. Catal.84. 1897-1904 (1994)

T. Yashima 等人：“环己酮肟在沸石晶体外表面上的贝克曼重排”螺柱。