Phenylacetic acid can be easily prepared from alkaline salts by acidification etc. according to widely conventional techniques.
Phenylacetic acid is known compound having many applicative possibilities in the industry.
Phenylacetic acid may be considered as an important intermediate for the preparation of perfumes (phenyl-ethyl phenyl acetate, benzyl phenylacetate, etc.) and in the field of pesticides, such as the ethyl ester of the dimethyl-dithiophosphoryl-phenylacetic acid known under the trade name Cidial, etc.
Several methods of synthetising phenylacetic acid are therefore known. For example, phenylacetic acid may be prepared by reacting benzyl chloride with alkaline cyanides and by successively saponifying the obtained nitrile to phenylacetic acid. Such method comprises more than one step, further complicated by the use of reagents such as cyanides difficult to handle, and involving operative risks and possible environmental pollutions, also because of the simultaneous formation of ammonium sulphate as by-product. The industry's interest in the aforesaid method is therefore rather sparing.
Phenylacetic acid is also obtainable, according to other methods described in the literature, by carbonylation of benzyl halides in an alkaline medium in the presence of catalyst systems based on metal-carbonyl complexes of Ni, Co.
Finally, it is also known how to prepare esters of phenylacetic acid by carbonylation of benzyl chloride in the presence of a catalyst system based on salts of cobalt hydrocarbonyl in hydroalcoholic solvents.
These methods, however, exhibit various drawbacks residing predominantly in the use of high pressures, in the necessity of preparing the catalyst separately, in the unsatisfactory reaction yields and rates, in the use of special solvents, and so on. These drawbacks, substantially, badly affect such methods for the purposes of the industrial applications thereof.
USPTO Backgrounds
USPTO Backgrounds