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

1987年我们研究了甲烷氧化偶联制乙烷和乙烯。我们的代表性结果和结论如下：1。氧化钐是甲烷和氧气反应生成C_2烃类（乙烷和乙烯）的活性最高的催化剂。在750 ℃时，C_2烃的时空产率可达3mol/g·h，此时C_2烃的选择性较高（64%）。2. LiCl添加NiO后，乙烯的选择性很好。LiCl的加入抑制了主体NiO对甲烷和C_2烃深度氧化的催化活性，并促进了后续反应CH_4C_2H_6C_2H_4。3.上述催化剂的动力学结果可以用反应机理来解释，即反应的速率控制步骤是吸附在催化剂表面的分子氧从CH_4中夺取H。4.在LiNiO_2催化剂上，C_2-烃是通过催化剂的氧化还原反应生成的 ...更多信息 yst. LiNiO_2的晶格氧原子对C_2烃的生成具有特别的活性和选择性。CH_4分子在Ni ^（3+）-O ^（3+）上容易解离，速率控制步骤是CH_3基团在Ni ^（3+）-O ^（3+）上偶联生成乙烷。<2->1. B_2O_3加FeNbO_4的催化剂对甲烷和氧气生成甲醛的反应具有最高的活性和选择性。FeNbO_4提供了活泼的晶格氧原子，这些氧原子是破坏C-H键和产生甲醛所必需的。B_2O_3通过减少甲醛的分解和深度氧化而提高了甲醛的选择性。2.动力学结果表明，在&gt; 600 ℃的高温下，CH_4分子撞击催化剂表面时受到振动激发，活性氧从CH_4分子中夺取H。该模型也适用于除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