Department of Chemical Engineering and Center for Combustion Studies, Yale University, New Haven, Connecticut 06520-8286, United States.
Environ Sci Technol. 2011 Mar 15;45(6):2498-503. doi: 10.1021/es103733q. Epub 2011 Feb 17.
Sooting tendencies have been measured for 186 oxygenated and 89 regular hydrocarbons under controlled laboratory conditions. The test compounds include alcohols, ethers, aldehydes, ketones, esters, alkanes, alkenes, and cycloalkanes ranging in size from methanol to isododecane. Sooting tendency was characterized with a new method based on measuring particle concentrations in methane/air nonpremixed flames when 1000 ppm of each test compound was added to the fuel. This method offers high precision and high sensitivity to the direct chemical effects of the additive. The results provide a wide-ranging yet detailed quantitative picture of how fuel oxygen affects soot formation, which will be useful for optimizing the soot-reducing benefits of oxygenated renewable fuels. The measured sooting tendencies of 1-alcohols are similar to those of n-alkanes with the same number of carbon atoms, while those of secondary alcohols are slightly higher. Aldehydes and ketones soot the same as n-alkanes with one less carbon atom. The sooting tendencies of esters depend strongly on molecular structure and increase in this order: methyl and ethyl esters < carboxylic acids, propyl esters, and n-alkanes < butyl and pentyl esters. The high sooting tendencies of the secondary alcohols and higher esters suggest that four-center and six-center reaction pathways are important.
在受控的实验室条件下，已经测量了 186 种含氧和 89 种普通烃的结炭倾向。测试化合物包括醇、醚、醛、酮、酯、烷烃、烯烃和环烷烃，大小从甲醇到异十二烷。通过在甲烷/空气无预混火焰中测量当燃料中加入 1000ppm 的每种测试化合物时的颗粒浓度，用一种新的方法来描述结炭倾向。该方法对添加剂的直接化学效应具有高精度和高灵敏度。研究结果提供了一个广泛而详细的定量图片，说明燃料氧如何影响炭黑的形成，这对于优化含氧可再生燃料的减少炭黑的益处将是有用的。1-醇的结炭倾向与具有相同碳原子数的正构烷烃相似，而仲醇的结炭倾向略高。醛和酮与少一个碳原子的正构烷烃结炭程度相同。酯的结炭倾向强烈依赖于分子结构，并按以下顺序增加：甲基和乙基酯 < 羧酸、丙基酯和正构烷烃 < 丁基和戊基酯。仲醇和高酯的高结炭倾向表明，四中心和六中心反应途径很重要。
