CAJ | 학술논문

采用脉冲微反装置,在反应温度为550~650℃,低转化率(小于15%)下,研究了正辛烷在石英砂和ZRP分子筛上的热裂化和催化裂化反应,分析了甲烷的生成机理。结果表明,正辛烷热裂化时,乙烯、丙烯和正丁烯是初始产物,甲烷由4种反应路径生成。当反应温度为600℃时,甲基自由基攻击碳链端部C-H键生成甲烷。中部C-H键脱氢形成的辛基自由基在端部C-C键断裂的活化能较高,仅在高温下生成甲烷。正辛烷在ZRP分子筛上主要发生质子化裂化反应,正构烷烃占有相当比重,甲烷由质子化裂化步骤生成。热裂化与质子化裂化对甲烷贡献的对比可知,当反应温度低于600℃时,甲烷由质子化裂化反应生成；在高温下,热裂化反应决定甲烷选择性。
채용맥충미반장치,재반응온도위550~650℃,저전화솔(소우15%)하,연구료정신완재석영사화ZRP분자사상적열열화화최화열화반응,분석료갑완적생성궤리。결과표명,정신완열열화시,을희、병희화정정희시초시산물,갑완유4충반응로경생성。당반응온도위600℃시,갑기자유기공격탄련단부C-H건생성갑완。중부C-H건탈경형성적신기자유기재단부C-C건단렬적활화능교고,부재고온하생성갑완。정신완재ZRP분자사상주요발생질자화열화반응,정구완경점유상당비중,갑완유질자화열화보취생성。열열화여질자화열화대갑완공헌적대비가지,당반응온도저우600℃시,갑완유질자화열화반응생성；재고온하,열열화반응결정갑완선택성。
The thermal and catalytic cracking reactions of n-octane were carried out in a temperature range of 550~650℃ with low conversions ( x<15%) in a pulse micro-reactor over quartz and ZRP zeolite. Reaction mechanism of methane formation was analyzed. The results showed that ethylene, propylene and n-butylene were primary products and four paths contributed to methane formation in thermal cracking of n-octane. At 600 ℃, dehydrogenation of terminal C-H bond in the chain attacked by methyl radical led to methane production. Due to higher activation energy of cleavage of terminal C-C bond in octyl radical formed via dehydrogenation of central C-C bond, only methane can form at higher temperature. Protolytic cracking was predominant with relatively remarkable yield of normal paraffin in catalytic cracking of n-octane over ZRP zeolite. Methane was produced by protolytic cracking route as well. By comparison of methane formation between thermal and protolytic cracking, it revealed that methane formed through protolytic cracking below 600℃ while thermal cracking dominated the selectivity of methane at higher reaction temperatures.