Simultaneous Crystallization

Although hand-sorting of the d and l crystals (as originally performed by Pasteur on sodium ammonium tartrate) can occasionally be a useful technique, the localization of the crystallization of each enantiomer on suitably disposed d and l seeds represents an improvement of greater practical interest. In small-scale preparations, one can utilize a small number of d and l seeds sufficiently separated from one another in the same crystallizer, and the large crystals which are eventually formed are collected manually. Large-scale applications utilize pairs of crystallization chambers, each one being loaded with a large amount of seeds of one enantiomer. The system is then continuously fed with a circulating, slightly supersaturated, racemic solution. Such processes have been proven to be valuable for continuous large-scale productions such as those developed by Haarmann & Reimer for (— )-menthol (resolved as its benzoate), and Merck for l-a-methyldopa (resolved as its nitrile precursor).

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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