摘要
针对直接合成法合成甲基氯硅烷单体,系统考察了添加微量Al粉对该反应的影响及其作用机理。分别在4%和10%铜浓度下,通过在线色谱分析的方法研究了添加Al粉对反应速率和M2选择性的影响。实验结果表明,添加Al粉可以很大程度上增加反应速率,缩短反应诱导期,但是Al粉的添加量超过一定量后会急剧降低反应选择性。建议工业中添加Al粉的量不应超过0.25%。通过SEM观察反应触体,发现添加铝粉可以改变触体反应活性中心的形貌,推测Al粉的作用主要是去除Si颗粒表面的氧化层,形成更多的缺陷,有利于催化剂与Si颗粒更好地结合。通过XRD对触体进行分析,发现添加Al粉后形成了更多的活性组分η相,从而加速了反应的进行。
The effects of A1 addition on the reaction rate of the direct synthesis reaction of methylchlorosilane monomer and the M2 （dimethyldichdorosilane）selectivity were studied by on-line chromatogram method at the copper concentration 4% and 10% respectively. The experimental results show that the introduction of A1 powder is able to increase reaction activity evidently and reduce the induction time previous to the reaction. However, if the A1 added dosage is beyond certain amount, it could drastically lower the M2 selectivity. It is therefore suggested that in the industry production the addition of A1 should be lower than 0.25%. The SEM micrograph shows that the morphology of contact mass is changed and more irregularly reaction centers are formed after adding A1. This implies that the main function of A1 added is to dismantle the thin SiO2 layer around the Si particle and create more defects on the surface of Si, both of these are in favor of better combination between catalyst and fresh Si surface. Simultaneously, more η-phase is found by the XRD pattern and therefore the reaction is accelerated.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2005年第6期803-807,共5页
Journal of Chemical Engineering of Chinese Universities
关键词
直接反应
甲基氯硅烷
Al粉
反应速率
选择性
η-相
direct reaction
methyldichlorosilane
A1 powder
reaction rate
selectivity
η-phase
