Synthesis of ethylene, methanol and formaldehyde by partial oxidation of methane.

1987年，我们研究了甲烷氧化偶联生成乙烷和乙烯。我们的代表性结果和结论如下：1. 氧化钐是甲烷和氧气生成c_2 -碳氢化合物（乙烷和乙烯）最活跃的催化剂。750℃时，c_2 -烃的时空产率可达3 mol/g.h，对c_2 -烃的选择性较高（64%）。2. LiCl加入NiO制得乙烯，具有良好的选择性。LiCl的加入抑制了载体NiO对甲烷和c_2烃深度氧化的催化活性，促进了CH_4 C_2H_6 C_2H_4的连续反应。3. 用上述催化剂观察到的动力学结果可以用反应机理很好地解释，反应速率决定步骤是催化剂表面吸附的分子氧从CH_4中提取H。4. 在LiNiO_2催化剂的情况下，通过催化剂的氧化还原生成c_2 -碳氢化合物。LiNiO_2的晶格氧原子对c_2 -碳氢化合物的形成具有特别的活性和选择性。CH_4分子在Ni^<3+>- o ^<2->位点上容易解离，其速率决定步骤是CH_3基团在这些位点上偶联生成乙烷。1988年，我们研究了甲烷部分氧化生成甲醛和甲醇。1. B_2O_3和FeNbO_4是甲烷和氧气生成甲醛的活性和选择性最高的催化剂。FeNbO_4提供破坏C-H键和生成甲醛所必需的活性晶格氧原子。B_2O_3通过减少甲醛的分解和深度氧化，提高了对甲醛的选择性。2. 动力学结果表明，CH_4分子在60 ~ 600℃高温下撞击催化剂表面时被振动激发，活性氧从这些CH_4分子中提取H。CH_4活化模型也适用于除LiNiO_2以外的各种催化剂上的甲烷氧化偶联反应。少

In 1987 we studied on oxidative coupling of methane into ethane and ethylene. Our representative results and conclusions are as follows; 1. Samarium oxide was the most active catalyst for the formation of C_2-hydrocarbons (ethane and ethylene) from methane and oxygen. At 750 C, the space time yield of C_2-hydrocarbons reached to 3 mol/g.h, when the selectivity to C_2-hydrocarbons was fairly high (64%). 2. LiCl added NiO produced ethylene with excellent selectivity. The roles of the added LiCl are to inhibit the catalytic activity of the host NiO for deep oxidations of both methane and C_2-hydrocarbons and to enhance the successive reaction CH_4 C_2H_6 C_2H_4. 3. The kinetic results observed with above catalysts can be explained well in terms of the reaction mechanism that the rate determining step is the abstraction of H from CH_4 by molecular oxygen species adsorbed of the catalyst surface. 4. In the case of LiNiO_2 catalyst, C_2-hydrocarbons were formed through the redox of the catal … More yst. The lattice oxygen atoms of LiNiO_2 are especially active and selective for the formation of C_2-hydrocarbons. CH_4 molecules disociate easily on Ni^<3+>-O^<2-> sites and the rate determining step was the coupling of CH_3 groups on these sites to form ethane.In 1988 we studied on partial oxidation of methane into formaldehyde and methanol. 1. B_2O_3 added FeNbO_4 was the most active and selective catalyst for the formation of formaldehyde from methane and oxygen. FeNbO_4 supplies reactive lattice oxygen atoms which are necessary for breaking C-H bond and producing formaldehyde. B_2O_3 improves the selectivity to formaldehyde by reducing both the decomposition and deep oxidation of the formed formaldehyde. 2. The kinetic results suggest that the CH_4 molecules are vibrationally excited upon their impact onto the catalyst surface at high temperatures >600 C and that the active oxygen species abstract H from these CH_4 molecules. This model for CH_4 activation can also be applicable to oxidative coupling of methane over various catalysts except for LiNiO_2. Less