Alpha-polyoxymethylene, formaldehyde

Preparation. Alplia-polyosymethylene cannot )o obtained by dehydrating formaldehyde. solutions at loiv temperatures (below 100°C) b> purely physical methods. Alore sti cmioiis procedures involving the use of alkaline and acidic catalysts or dehydrating agents are required,. Alpha polyoxymethylene can also be obtained by the action of heat on para formaldehyde . ... 

Bdhme prepared chloromethyl ethyl thioether (or chloromethyl ethyl sulfide) in 60 i>e.r cent yield Iry saturating an ice-cold mixture of alpha-polyoxymethylene and ethyl mercaptan with hydrogen chloride until a clear liquid was obtained. After treatment with calcium chloride, the product separated as a separate phase with loss of unreacted hydrogen chloride, and was purified by dtstillation. It is a colorless liquid with an unpleasant odor which boils at 128-131°C. It is quite stable when pure. On treatment with water, it- forms methylene diethyl mercaptal mth liberation of formaldehyde and hydrogen chloride. 

The. peciric utility of the ariou.s methods which we have listed will be further discussed in the sep.arate sections of this chapter. Those not chosen by Biichi have been included because of their utility in the presence of inipuritiei- which do not noraialh occur in commercial formaldehyde, but which are. sometimes encountei ed in connection with its utilisation. In general, these methods are also applicable to paraformaldeh -de and alpha-polyoxymethylene, making it possible to determine the formaldehyde content of these polymers. This Is definitely the case for methods (l)r (2) and (3). 

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