Sugar industry, continuous large-scale

The sugar-containing feedstock is next inoculated with yeast. Continuous operation is usually done for small-scale production of high-quality spirits such as beverages and discontinuous (batch) operations are used in large-scale systems for production of ethanol as a raw material for the chemical industry. After the fermentation, the yeast is removed from the slurry and recycled. 

The syntheses of some C-labelled key intermediates from CO are illustrated In Scheme 1.1. These compounds are prepared on a relatively large-scale by manufacturers. Yields are high as the methods are frequently scaled-down versions of industrial processes or utilise specialised equipment, they are not always suitable for use in the majority of chemical laboratories. For example, [ Cjmethanol is prepared by catalytic reduction of with hydrogen under pressure [59]. The method can be automated and used for the continuous preparation of large batches. In the majority of cases, the user may well find that he is unable to prepare intermediates of this type as cheaply as they can be purchased. Scheme 2.2 illustrates the preparation of widely used N-labelled compounds. More detailed reviews of the basic synthetic processes have been published [15, 26,60—63] and many of the preparations have been described in individual publications. Some more specialised labelled compounds such as amino acids, fatty acids, organic heterocycles, and sugars are also available commercially. 

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