Effect of pH on ether, ester, and carbonate hydrolysis in high-temperature water
Effect of pH on ether, ester, and carbonate hydrolysis in high-temperature water
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DOI：
10.1021/ie0702882
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发表时间：
2008-02-06
影响因子：
4.2
通讯作者：
Savage, Phillip E.
中科院分区：
文献类型：
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作者：
Comisar, Craig M.;Hunter, Shawn E.;Savage, Phillip E.
我们研究了在高温液态水中二苯醚、苄基叔丁基醚、甲基叔丁基醚、苯甲酸甲酯和二苯碳酸酯的水解，无论是否添加酸或碱。在所研究的化合物中，H+的表观反应级数均不超过0.2。这一结果表明，这些化合物在高温水中（HTW）的水解并不遵循特定酸催化（H+反应级数= 1.0）的动力学，而在环境温度下的水解则是如此。在接近中性的条件下，HTW系统中较大的热能使得水分子的质子化速度比HI的质子化速度更快。由于水催化的路径更快，在没有添加酸的HTW中，这些酸催化反应的发生并不是因为离子产物K-w值的升高。这一发现与这一领域的传统观点相矛盾。
We examined the hydrolysis of dibenzyl ether, benzyl t-butyl ether, methyl t-butyl ether, methylbenzoate, and diphenylcarbonate in high-temperature liquid water, both with and without added acid or base. The apparent reaction order for H+ did not exceed 0.2 for any of the compounds investigated. This result indicates that hydrolysis of these compounds in high-temperature water (HTW) does not follow the kinetics expected for specific acid catalysis (H+ reaction order = 1.0), as does the hydrolysis at ambient temperatures. Rather, the greater thermal energy in the HTW system allows protonation by water molecules to become faster than protonation by HI at near-neutral conditions. Because the water-catalyzed path is faster, the occurrence of these acid-catalyzed reactions in HTW with no added acid is not due to the elevated value of K-w, the ion product. This finding contradicts the conventional wisdom in this field.