Parahydroxy-benzoic acid

In 1973, the Federal Trade Commission modified the generic definition of polyester to include in the polyester category materials that previously were polyester ethers or benzoate polyesters. As a result, the fiber known as poly (ethylene oxybenzoate) or PEB and manufactured under the trade name A-Tell in Japan came to be known as polyester. This material is made by reacting parahydroxy-benzoic acid and ethylene oxide to give... 

Reduction of the melting point by copolymerization is illustrated by the two systems shown in Figure 3, in which symmetrical polyesters are modified by copolymerization with parahydroxy-benzoic acid (PHB). In the case of poly(hydroquinone naphthalene-2, 6-dicarboxylate), its melting point is reduced from 580 C to about 325 C by copolymerization with 70% PHB. More PHB increases the melting point until it reaches 600 C for pure poly-PHB. ... 

The study of LC copolyesters started with the polyester of poly(ethylene tere-phthalate) (PET) and parahydroxy benzoic acid (PHB) by Jackson and Kuhfuss, 1974 (Jackson Jr. and Kuhfuss, 1996). It turned out that the copolyesters are heterogeneous consisting of flexible (ET-rich) and rigid (HB-rich) blocks. Thus, the copolyester itself, with a composition of 0.6 mole fraction of HB, segregates into... 

Membrane Active—Protonophores Weak organics acids, parabens (parahydroxybenzoates and esters of parahydroxy-benzoic acid). 

Given the table of data below for the reaction of o-diphenol oxidase with catechol in the presence of parahydroxy benzoic acid (a competitive inhibitor), draw the Lineweaver-Burk plot and find the slope of the graph and use the value of the y-intercept (1/Vmax) to obtain the modified Am value. Calculate the value of Am from the slope and compare it with the reciprocal... 

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See also in sourсe #XX -- [ ]

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