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首页> 外文会议>Conference on Silicon for the Chemical Industry VI; 20020617-20020621; Loen; NO >Direct production of silicones from sand
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Direct production of silicones from sand

机译：从沙子直接生产有机硅

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We describe the optimised reaction between SiO_2, base and dimethylcarbonate (DMC) to make tetramethoxysilane (Q'). Diatomaceous earth, a natural SiO_2 source, was very active for the Q'-forming reaction; silicon dioxide utilization > 60% was achieved. High throughput screening was employed to find other SiO_2 sources useful for formation of Q'. A 32-column, fixed bed reactor was constructed and used to screen the reactivity of over 200 silicate minerals with base and DMC at 300℃. Other active silicates for formation of Q' include opal and Li, Co and ca silicates. The reaction of Q' with NaH was explored in a fixed bed reactor. When Q' was passed through a bed of NaH up to 200℃, (MeO)_3SiH (T'H) formed and at 325℃ MeSi(OMe)_3 (T') was produced as well. T'H reacts with base generated in the reaction to form T; significant amounts of disproportionation occurs as well to form Q' and SiH_4. Deuterium labelling studies were performed and these data suggested a mechanism whereby NaH reacts with T'H to form a silyl species. The silyl species in turn acts as a nucleophile, attacking a methoxy at a second Q' leading to transfer of an intact methyl group and formation of the Si-C bond. The use of Q' was explored as a source of SiH_4 by reaction with NaH under different conditions man above. Finally the use of Q' was investigated as a source of SiO_2 under flame conditions.
机译：我们描述了SiO_2，碱和碳酸二甲酯（DMC）之间的最佳反应，以制备四甲氧基硅烷（Q'）。硅藻土是一种天然的SiO_2来源，对于形成Q'的反应非常活跃。二氧化硅利用率达到60％以上。采用高通量筛选来发现其他可用于形成Q'的SiO_2源。建造了一个32柱的固定床反应器，用于筛选300℃以上200多种硅酸盐矿物与碱和DMC的反应性。用于形成Q′的其他活性硅酸盐包括蛋白石和Li，Co和Ca硅酸盐。在固定床反应器中研究了Q'与NaH的反应。当Q'经过高达200℃的NaH床时，会形成（MeO）_3SiH（T'H），在325℃时也会生成MeSi（OMe）_3（T'）。 T'H与反应中生成的碱反应形成T;大量的歧化也会发生，形成Q'和SiH_4。进行了氘标记研究，这些数据表明了NaH与T'H反应形成甲硅烷基的机理。甲硅烷基又起亲核试剂的作用，在第二个Q'上攻击甲氧基，导致完整的甲基转移并形成Si-C键。通过在上述不同条件下与NaH反应，探索了Q'的使用作为SiH_4的来源。最后，研究了在火焰条件下使用Q'作为SiO_2的来源。

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