Development of Direct Synthesis of Alkoxysilanes from Silica by Gas-Solid Reactions

二氧化硅气固反应直接合成烷氧基硅烷的研究进展

• 批准号: 05555216
• 负责人: ONO Yoshio
• 金额: $ 4.35万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Developmental Scientific Research (B)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-05555216/
• 关键词: Silica; Dialkylcarbonates; Alkoxysilanes; アルコキシシラン

In the reaction of silica with dimethyl carbonate to give tetramethoxysilane, the effect of physical properties of silica on the reaction rate of the silica was examined. The silica, which was obtained by drying colloidal silica at 150ﾟC,Was calcined at various temperatures. The silica sample, on which potassium hydroxide as a catalyst was supported by 5wt.%, was loaded in a fixed-bed flow reactor. After heated at 260ﾟC for 1 h under a helium stream, the sample was subjected to contact with dimethyl carbonate vapor at 260ﾟC.For the calcination temperatures of 400-600ﾟC,the rate was greater at the higher calcination temperatures, while it was smaller for the 700-900ﾟC calcinations. The reaction rate was not controlled by the pore distribution or surface area of silica sample. Generation of new reactive silica surface with the reaction proceeding was a determining factor of the rate. Silica was found to react also with diethyl carbonate to give tetraethoxysilane. The effect of reaction variables on the rate of silica consumption was examined.Hydrous titanium oxide was found to react with diethyl carbonate to yield tetraethoxytitanium. thus, using potassium hydroxide (5wt.%) as a catalyst, a 93% yield of tetraethoxytitanium was obtained at 230ﾟC in an autoclave.The effect of reaction temperature and the temperature of calcining the hydrous titanium oxide on the tetraethoxytitanium yield was examined.

在二氧化硅与碳酸二甲酯反应生成四甲氧基硅烷的过程中，考察了二氧化硅的物理性质对二氧化硅反应速率的影响。将硅胶在150 ℃下干燥得到的二氧化硅在不同温度下煅烧。在其上负载有5 wt.%氢氧化钾作为催化剂的二氧化硅样品，装载在固定床流动反应器中。在260 ° C下在氦气流下加热1小时后，使样品在260 ° C下与碳酸二甲酯蒸气接触。对于400-600 ° C的煅烧温度，在较高煅烧温度下的速率较大，而对于700-900 ° C煅烧的速率较小。反应速率不受二氧化硅样品的孔分布或表面积的控制。随着反应的进行，新的活性二氧化硅表面的生成是反应速率的决定因素。发现二氧化硅也与碳酸二乙酯反应得到四乙氧基硅烷。考察了反应条件对二氧化硅消耗速率的影响，发现水合氧化钛与碳酸二乙酯反应生成四乙氧基钛。因此，使用氢氧化钾（5重量%），以水合氧化钛为催化剂，在230 ℃下反应，四乙氧基钛的产率可达93%，考察了反应温度和煅烧温度对四乙氧基钛产率的影响。