6.3 Synthesis of Metyltrifenylmetyleter (Tritylmetyleter) [11/02/2016]
Introduction: The purpose of this lab was to attempt a full synthesis of Methyl Trityl Ether from Triphenylmethanol and Methanol using Sulfuric acid (H2SO4) as a catalyst.
The reaction between triphenylmethanol and methanol is a Sn1 reaction which starts due to the acidity of the solution. An -OH group is a poor leaving group, however and -H2O group is not. The oxygen on the -OH group of the triphenylmethanol can commence a nucleophilic attack on the H+ found in the solution thanks to the H2SO4, this results in an -OH2 group forming at the triphenyl, which as stated before is a good leaving group, hence it leaves the now positively charged triphenyl. The slight negative charge of the oxygen in the methanol allows it to bind to the positively charged triphenyl making a positively charged transition state. The single hydrogen bound to the oxygen is then returned to the
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Regarding the reaction, Scheme 2-3, one of the free electron pairs of the Oxygen is the HOMO and the empty sp3 orbital of the Carbon is the LUMO. In Scheme 3-4 the oxygen of the water (or perhaps some of the remaining methanol) is the HOMO and the antibinding sp3O-H is the LUMO. 1
During the heating of the solution in which the reaction, Scheme 1-4 takes place, thin-layer chromatography is used to see whether the reaction has been fully, or near fully completed or not. Using a reference of triphenylmethanol to compare. The triphenylmethanol should move slower along the plate of silicon as it has a higher chance of binding to the plate compared to the methyl trityl ether (as alcohols bind stronger to silicon plates than ethers). When the reaction is complete, the process of filtration is to begin.
Experimental/Result:
Chemical
Mass (g)
Mole (mmol)
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