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(2021·海门模拟)
甲醛中木材加工、医药等方面有重要用途。甲醇利用脱氢法可制备甲醛,主要反应为:CH3OH(g)
HCHO(g)+H2(g) ∆H=+85.2kJ∙mol-1。Na2CO3是甲醇脱氢制甲醛的催化剂,有研究指出,催化反应的部分机理如下:
历程ⅰ:![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmtext%3EC%3C%2Fmtext%3E%3Cmsub%3E%3Cmrow%3E%3Cmtext%3EH%3C%2Fmtext%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmtext%3E3%3C%2Fmtext%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3Cmtext%3EO%3C%2Fmtext%3E%3Cmtext%3EH%3C%2Fmtext%3E%3Cmo%3E%E2%86%92%3C%2Fmo%3E%3Cmo%3E%E2%8B%85%3C%2Fmo%3E%3Cmtext%3EH%3C%2Fmtext%3E%3Cmo%3E%2B%3C%2Fmo%3E%3Cmo%3E%E2%8B%85%3C%2Fmo%3E%3Cmtext%3EC%3C%2Fmtext%3E%3Cmsub%3E%3Cmrow%3E%3Cmtext%3EH%3C%2Fmtext%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmtext%3E2%3C%2Fmtext%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3Cmtext%3EO%3C%2Fmtext%3E%3Cmtext%3EH%3C%2Fmtext%3E%3C%2Fmath%3E)
历程ⅱ:![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmo%3E%E2%8B%85%3C%2Fmo%3E%3Cmtext%3EC%3C%2Fmtext%3E%3Cmsub%3E%3Cmrow%3E%3Cmtext%3EH%3C%2Fmtext%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmtext%3E2%3C%2Fmtext%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3Cmtext%3EO%3C%2Fmtext%3E%3Cmtext%3EH%3C%2Fmtext%3E%3Cmo%3E%E2%86%92%3C%2Fmo%3E%3Cmo%3E%E2%8B%85%3C%2Fmo%3E%3Cmtext%3EH%3C%2Fmtext%3E%3Cmo%3E%2B%3C%2Fmo%3E%3Cmtext%3EH%3C%2Fmtext%3E%3Cmtext%3EC%3C%2Fmtext%3E%3Cmtext%3EH%3C%2Fmtext%3E%3Cmtext%3EO%3C%2Fmtext%3E%3C%2Fmath%3E)
历程ⅲ:![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmo%3E%E2%8B%85%3C%2Fmo%3E%3Cmtext%3EC%3C%2Fmtext%3E%3Cmsub%3E%3Cmrow%3E%3Cmtext%3EH%3C%2Fmtext%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmtext%3E2%3C%2Fmtext%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3Cmtext%3EO%3C%2Fmtext%3E%3Cmtext%3EH%3C%2Fmtext%3E%3Cmo%3E%E2%86%92%3C%2Fmo%3E%3Cmn%3E3%3C%2Fmn%3E%3Cmo%3E%E2%8B%85%3C%2Fmo%3E%3Cmtext%3EH%3C%2Fmtext%3E%3Cmo%3E%2B%3C%2Fmo%3E%3Cmtext%3EC%3C%2Fmtext%3E%3Cmtext%3EO%3C%2Fmtext%3E%3C%2Fmath%3E)
历程ⅳ:![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmo%3E%E2%8B%85%3C%2Fmo%3E%3Cmtext%3EH%3C%2Fmtext%3E%3Cmo%3E%2B%3C%2Fmo%3E%3Cmo%3E%E2%8B%85%3C%2Fmo%3E%3Cmtext%3EH%3C%2Fmtext%3E%3Cmo%3E%E2%86%92%3C%2Fmo%3E%3Cmsub%3E%3Cmrow%3E%3Cmtext%3EH%3C%2Fmtext%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmtext%3E2%3C%2Fmtext%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3C%2Fmath%3E)
![](//tikupic.21cnjy.com/2022/01/17/a4/6b/a46b3ee65b238c89884906d58bf8af06.png)
如图所示为在体积2L的恒容容器中,投入1molCH3OH,在碳酸钠催化剂作用下,经过5min反应,测得甲醇转化率与甲醛的选择性与温度的关系(甲醛的选择性:转化的CH3OH中生成HCHO的百分比),下列有关说法正确的是( )
A . 600℃时,前5min内生成甲醛的平均速率v(HCHO)=0.055mol·L-1·min-1
B . 700℃时,反应历程ⅱ的速率小于反应历程ⅲ的速率
C . 脱氢法制甲醛中,在高温高压条件下更有利于提高平衡产率
D . 反应历程ⅰ的活化能大于CH3OH(g)
HCHO(g)+H2(g)的活化能