No abstract

Distilled spirits are subject to post-distillation ethyl carbamate formation in the presence of appropriate precursors. Freshly distilled grain whisky, produced by the continuous distillation Coffey still process, normally contains ethyl carbamate concentrations not exceeding 20 ppb (normalized to 43% v/v alcoholic strength). Further ethyl carbamate formation, dependent upon the presence of trace anionic precursors such as cyanate, cyanide, and copper cyanide complexes, may take place during normal maturation in oak casks. Related but different mechanisms may induce ethyl carbamate formation under normal daylight and artificial light in the laboratory. Ethyl carbamate precursors convert into ethyl carbamate during the Initial three months of maturation and are not detectable in the final bottled product. Thus the final ethyl carbamate concentration in spirit is dependent upon the initial ethyl carbamate level measured after distillation plus ethyl carbamate formed from precursors. It is important during process control to monitor not only the ethyl carbamate level in freshly distilled spirit but also the spirit*s potential to form ethyl carbamate from precursors with the objective of minimizing these components in the freshly distilled and maturing spirit. A scheme for predicting final ethyl carbamate concentrations from precursor concentrations in freshly distilled spirit is presented.Key Words: Ethyl carbamate, ethyl carbamate precursors, distilled spirits, Scotch whisky, post-distillation formation, maturation. INTRODUCTONEthyl carbamate (CjHjOCONHj), otherwise known as urethane, is a naturally occurring compound present in most fermented foods and beverages20. However, it is a chemical carcinogen13 and this has led to concern in recent years about its presence at trace levels in alcoholic beverages.Canada introduced regulatory limits for various types of alcoholic beverage in 1985s and the United States agreed voluntary limits for whiskey and wines in 1987 which were applicable to new production from 1st January 1989". These actions have resulted in considerable attention being given to the development of methods for ethyl carbamate analysis and to investigations into mechanisms for its formation. This paper deals with aspects of its formation in Scotch whisky. Ough suggested in 1976 that an obvious source of natural ethyl carbamate was the hydrolysis of yeast carbamyl phos phate with ethanol, yielding phosphoric acid and ethyl car bamate20. Recent work has identified a range of N-carbamyl compounds including allantoin and citrulline and the closely related arginine which can react with ethanol to form ethyl carbamate9-21'22. Such pathways are important in alcoholic beverages such as beer and wine, where the final product remains associated with the solution from which it was fer mented, or distilled spirits where the ethyl carbamate formed during fermentation is subject to distillation into the spirit.Workers studying ethyl carbamate formation in stone fruit spirits associated its formation with yeast produ...

This contribution describes the operation of a pilot plant for the production of 3-exomethylene-7(R)-glutaroylaminocepham-4-carboxylic acid 1(S)-oxide (4a) by the electrochemical reduction of 3-acetoxymethyl-7(R)-glutaroylaminoceph-3-em-4-carboxylic acid 1(S)-oxide (3a). This conversion is a key step in a new process for the production of Ceftibuten (1). The scale-up of the electrochemical reduction was demonstrated using a commercial flow-cell. The use of a novel type of extended-area tin cathode, which had been shown on a laboratory scale to produce significant improvements in the process, was successfully implemented in an ICI FM21-SP commercial-scale electrochemical reactor. † Ceftibuten was discovered by Shionogi and Co. Ltd., Osaka, Japan, and licensed to Schering Plough Corporation, Kenilworth, New Jersey. The drug is manufactured by Shionogi.

Gas chromatographic methods are described for the determination of naturally occurring ethyl carbamate in distilled spirits at levels as low as 5 ppb. Bottled products, such as whisky, gin and brandy, are extracted in the presence of n-propyl carbamate as internal standard and analysed by capillary column gas chromatography with either nitrogen specific or mass spectrometric detection. A shorter extrac tion procedure is satisfactory when the more sensitive and selective mass spectrometric detection is used.Direct sample injection without extraction may be used for higher alcoholic strength cask and new-make samples. Analysis of 181 blended Scotch whisky samples indicated ethyl carbamate con centrations ranging from 20 to 75 ppb. Concentrations in 48 malt whiskies ranged from 15-100 ppb. Ethyl carbamate was not detected in gin, vodka and rectified neutral alcohol. All concentrations in bottled product fell below the Canadian limit of 150 ppb in distilled spirits.