Staudinger hydration

In the first microreactor, the azide intermediate is formed by nucleophilic substitution. The azide intermediate is submitted to Staudinger hydration with triphenylphosphine in a subsequent second microreactor [35]. A phase-transfer catalyst moderates the initial reaction with efficient mixing by the microreactor. Production capacity of o-xylylenediamine in two subsequent glass microreactors exceeds 1 kg/day with an overall yield of 60%. Workup and isolation of the potentially hazardous intermediate are completely avoided between reaction steps, saving time and money and offering scale-independent safety levels. 

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The experimental techniques available to determine AWPCs and their limitations have been discussed by Staudinger and Roberts [2]. These authors also evaluated the effects of pH, compound hydration, compound concentration, cosolvent, cosolute, and salt effects, suspended solids, dissolved organic matter, and surfactants. The experimental data have been compiled by a number of different authors [2-11]. 

The reaction of hydrazine with chloroform and base to yield diazomethane was reported by Staudinger some sixty years ago but remained of limited utility. The application of 18-crown-6 mediated phase transfer catalysis to this reaction has made it a preparatively useful method. By this method, hydrazine hydrate can be conveniently converted to diazomethane in almost 50% yield (see Eq. 3.11) [16]. 

Dry injection of limestone and hydrated lime particles in desulfurization processes is currently under active development (Stouffer et al, 1986 Weinstein, 1989 Yoon et al, 1986). Furnace dry sorbent injection for SO2 control consists of injecting a dry pulverized calcium based material directly into furnace cavity of a coal fired boiler. The product CaS04 and unreacted sorbent particles are removed from the furnace together with fly ash. Fan and Satija (1984), Milne et al (1990b) Krammer and Staudinger (1991) reported kinetic data and model expressions which are applicable to dry injection systems. 

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