Miscellaneous Intermediates

Recent estimates of the atmospheric loading rate of acrolein from sources in the United States were not located. Anderson (1983) estimated the total loading rate of acrolein in 1978 to be 91,450 pounds from facilities involved in its production and use as a chemical intermediate. Loading rates from various industrial sources were as follows acrylic acid manufacturers, 15,175 pounds refined acrolein and glycerin manufacturers, 55,660 pounds methionine manufacturers, 18,150 pounds and miscellaneous intermediate uses, 2420 pounds. These loading rates were based on a total production volume of 350 million pounds for acrolein in 1978, with 87% of this volume consumed in the production of acrylic acid and its derivatives. 

C. Miscellaneous Intermediates of Solution Reactions of Organophosphorus Species... 

There are many other kinds of reactive intermediates, which do not fit into the previous classifications. Some are simply compounds that are unstable for various possible reasons, such as structural strain or an unusual oxidation state, and are discussed in Chapter 7. This book is concerned with the chemistry of carbocations, carbanions, radicals, carbenes, nitrenes (the nitrogen analogs of carbenes), and miscellaneous intermediates such as arynes, ortho-quinone methides, zwitterions and dipoles, anti-aromatic systems, and tetrahedral intermediates. This is not the place to describe in detail the experimental basis on which the involvement of reactive intermediates in specific reactions has been estabhshed but it is appropriate to mention briefly the sort of evidence that has been found useful in this respect. Transition states have no real hfetime, and there are no physical techniques by which they can be directly characterized. Probably one of the most direct ways in which reactive intermediates can be inferred in a particular reaction is by a kinetic study. Trapping the intermediate with an appropriate reagent can also be very valuable, particularly if it can be shown that the same products are produced in the same ratios when the same postulated intermediate is formed from different precursors. 

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