4- Hydroxy-benzoic acid distribution

Not all polyoxyethylene association complexes form by one-to-one complexation. The polyoxyethylene/p-hydroxy-benzoic acid-formaldehyde copolymer complex in methanol has been reported to form by stepwise complexation (120,121). Uncertainty regarding the type of complexation may be due to changes in molecular weight distribution via partial fractionation that occurs during the complexation process (122). 

Addnl Refs (Limited Distribution) A) A.T. Camp, Research, Development and Large-Scale Application of Temperature-Independent Double-Base Propellants A Brief Survey and History , IHSP 68-14 (1968) B) R.M. Abbott N.S. Gelber, Analysis of Lead and Copper Salts of Hydroxy-Substituted Benzoic Acids , PATR 4376 (1972)... 

Phenolic compounds are widely distributed in plant parts from the roots to the seeds and include phenolic acids, flavo-noids and tannins. The tannins may reduce protein digestibility (Ford and Hewitt, 1979) and perhaps the bioavailability of other nutrients. The flavonoids have been reported to have a number of nutritional and pharmacological activities (Kuhnau, 1976). Phenolic acids include benzoic and cinnamic acid derivatives. The benzoic acid derivatives include p-hydroxy-benzoic, protochate-chuic, vanillic, gallic and syringic acids. The cinnamic acids, p-coumaric, caffeic, ferulic and sinapic are found in most oilseeds used to prepare protein concentrates and frequently occur in the form of esters with quinic acid or sugars. Chlorogenic acid for example is an ester of caffeic acid and quinic acid and is found in several isomeric and derivatized forms. 

Phenolic acids and coumarins Two families of phenolic acids are widely distributed in plants - a range of substituted benzoic (Cg-Ci) acid derivatives and those derived from cinnamic (C -C ) acid. Both types of phenolic acids usually occur in conjugated or esterified form. The simpler types of benzoic acid derivatives include p-hydroxybenzoic, protocatechuic, vannilic, gallic and syringic acids, and the o-hydroxy salicylic and gentisic acids (Fig. 1). The cinnamic acids p-coumaric, caffeic, ferulic, and sinapic, are found in most oilseeds and occur frequently in the form of esters with quinic acid or sugars (Fig. 1). Chlorogenic... 

Several of the simple phenolic acids, including p-hydroxy-benzoic, vanillic, syringic and protocatechuic,are widely distributed amongst the angiosperms. The first three are also present widely in gymnosperms and ferns. In addition,... 

Table 5. Distribution of C from COOH-labelled p-hydroxy-benzoic, vanillic and syringic acids after uptake by v heat seedlings over six days (from Flaig ).

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