Method for preparing a dialkyl carbonate, and its use in the preparation of diaryl carbonates and polycarbonates
AssigneeGeneral Electric Company
InventorsEugene Pauling Boden, Ignacio Vic Fernandez
Life of this patent
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Abstract
Unexpected corrosion of downstream sections of a dialkyl carbonate manufacturing apparatus has been traced to alkyl chloroformate impurities, which slowly decompose to yield hydrochloric acid. An improved process and apparatus for dialkyl carbonate synthesis reduce corrosion by physically removing or chemically decomposing the alkyl chloroformate impurities within the corrosion-resistant upstream sections of the apparatus.
Claims44
A method of preparing a dialkyl carbonate, comprising:
- reacting an alkanol, oxygen, carbon monoxide, and a catalyst to form a mixture comprising a dialkyl carbonate, an alkyl chloroformate, hydrochloric acid, water, carbon dioxide, and carbon monoxide;
- and
- removing alkyl chloroformate from said mixture.
A method of preparing a dialkyl carbonate, comprising:
- reacting an alkanol, oxygen, carbon monoxide, and a catalyst to form a mixture comprising a dialkyl carbonate, an alkyl chloroformate, hydrochloric acid, water, carbon dioxide, and carbon monoxide;
- reducing the concentration of said alkyl chloroformate in said mixture to less than about 500 parts per million by weight, based on the total weight of said mixture, while removing less than about 10 weight % of said dialkyl carbonate;
- and
- removing hydrochloric acid from said mixture.
A method of preparing a dialkyl carbonate, comprising:
- reacting an alkanol, oxygen, carbon monoxide, and a catalyst to form a first mixture comprising a dialkyl carbonate, an alkyl chloroformate, hydrochloric acid, water, carbon dioxide, and carbon monoxide;
- removing alkyl chloroformate from said first mixture to form a second mixture;
- and removing hydrochloric acid from said second mixture.
A method of preparing a dialkyl carbonate, comprising:
- reacting an alkanol, oxygen, carbon monoxide, and a catalyst to form a first mixture comprising a dialkyl carbonate, an alkyl chloroformate, hydrochloric acid, water, carbon dioxide, and carbon monoxide;
- removing hydrochloric acid from said first mixture to form a second mixture;
- and
- removing alkyl chloroformate from said second mixture.
A method of preparing dimethyl carbonate, comprising:
- combining methanol, oxygen, carbon monoxide, and a copper catalyst to form a first mixture comprising a vapor of dimethyl carbonate, a vapor of methyl chloroformate, hydrochloric acid, water, carbon dioxide, and carbon monoxide;
- removing a portion of said carbon dioxide and a portion of said carbon monoxide from said first mixture to form a second mixture;
- at least partially condensing said vapor of dimethyl carbonate and said vapor of methyl chloroformate to form a third mixture;
- removing at least about 90weights % of said methyl chloroformate and less than about 1 weight% of said dimethyl carbonate from said third mixture to form a fourth mixture;
- and
- removing hydrochloric acid from said fourth mixture.
A method of perparing dialkyl carbonate comprising:
- reacting alkanol, oxygen, carbon monoxide and a catalyst to form a first mixture comprising a vapor of alkyl carbonate, a vapor of alkyl chloroformate, hydrochloric acid, water, carbon dioxide and carbon monoxide;
- condensing the vapor of alkyl carbonate and the vapor of alkyl chloroformate and removing a portion of the carbon dioxide and a portion of the carbon monoxide from the first mixture to form a fully condensed second mixture;
- and
- removing alkyl chloroformate from the fully condensed second mixture.
Dependencies are inferred from the claim text.