| Summary: | 碩士 === 國立成功大學 === 化學學系 === 86 ===
Dimethyl carbonate (DMC) reacts with phenol (Ph) to give methyl phenyl carbonate and diphenyl carbonate(DPC) under catalytic condition. Without catalyst, refluxing of DMC and Ph do not give transesterification product in 48 hours. Meanwhile diphenyl carbonate can be heating up to 242℃ without decomposition.
Through preliminary test of 20 samples of compounds there showed that dibutyltin oxide (Bu2SnO) as well as titanium isopropoxide (Ti(0(i)Pr)4) give catalytic effect on this transesterification reaction.Poassium hydroxide (KOH) and potassium iodide (KI), on the other hand, promoted the formation ofaniole (CH3OC6H5), the remained 16 compounds showed no clear sign of assistance for the previous reactions.
The reaction is well affected by both the order of mixing of substance and the control of temperature. In the first process; mixing all substances together followed by refluxing would give poor result. In the second process; dissolving catalyst in phenol followed by addition of dimethyl carbonate would give better result. In comparison of the resultsof the two different process by their DPC: Ph value, the 1st process gives 0.83:1.00 while the 2nd process gives 6.29:1.00. The larger the value of DPC:Ph showes the better result of this transesterification reaction.
The using of toluene in this reaction showed some assistance, but not so much help as in using of excess dimethyl carbonate.
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