Results 181 to 190 of about 36,585 (232)

3-Ethoxy-4-hydroxybenzoic Acid in Human Urine

Nature, 1958
IN a recent communication1 an increased excretion of vanillic acid during the stress of motor-rally driving was reported. The 1958 Royal Automobile Club rally offered an opportunity to confirm this finding, and three samples of urine were collected from each of two subjects during the third and fourth days.
G A, HILL, J, RATCLIFFE, P, SMITH
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Thermotropic copolyesters of 4‐hydroxybenzoic acid

Makromolekulare Chemie. Macromolecular Symposia, 1989
AbstractCopolyesters of 4‐hydroxybenzoic acid were prepared by thermal polycondensation of 4‐acetoxybenzoic acid with various acetylated comonomers, such as 4‐mercaptobenzoic acid, 3‐hydroxybenzoic acid, N‐(4‐carboxyphenyl)4‐hydroxyphthalimide or hydroquinone in combination with 1,12‐dodecane bistrimellitimide.
Hans R. Kricheldorf, Arnd Conradi, Ralf Pakull, Gert Schwarz   +3 more
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Grouping of esters of 4-hydroxybenzoic acid for hazard assessment

Archives of Toxicology, 2023
Hazardous properties of a large number of esters of 4-hydroxybenzoic acid (parabens) have been proposed by ECHA to be assessed as a group. We recommend to restrict the grouping approach to short chain esters, i.e. methyl, ethyl, propyl and butyl paraben which are very similar in chemical structures, physicochemical properties, toxicokinetics, and ...
Thomas Colnot, Wolfgang Dekant, Helmut Greim   +2 more
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Antimicrobial effect of 4-hydroxybenzoic acid ester with glycerol

Journal of Clinical Pharmacy and Therapeutics, 2015
Parabens have been commonly used as preservatives in pharmaceutical and cosmetics industries for almost 50 years. These compounds are thermostable, pH-stable and inexpensive and have a wide antimicrobial effect. The antimicrobial activity of parabens in emulsion system is limited by their poor solubility in water phase, which is increasing with the ...
M, Kosová, I, Hrádková, V, Mátlová, D, Kadlec, J, Šmidrkal, V, Filip   +5 more
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Selective Synthesis of 4-Hydroxybenzoic Acid using Immobilized Cyclodextrin

Journal of Inclusion Phenomena, 1984
β-cyclodextrin immobilized with epichlorohydrin was used for the selective syntheses of 4-hydroxybenzoic acids from phenols and carbon tetrachloride in aqueous sodium hydroxide solutions. The selectivities were 100%, and the yields were larger than 80 mole%.
M. Komiyama, I. Sugiura, H. Hirai
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Synthesis of 4-Hydroxybenzoic Acid Derivatives in Escherichia coli

Journal of Agricultural and Food Chemistry, 2020
Hydroxybenzoic acids (HBAs) such as 4-hydroxybenzoic acid (4-HBA) and 3,4-dihydroxybenzoic acid (DHB; protocatechuic acid) and its ester with methanol (methylparaben [MP]) are known to have various functional biological properties, including antibacterial, anticancer, antidiabetic, antiaging, antiviral, and anti-inflammatory activities.
Han Kim, Song Yi Kim, Geun Young Sim, Joong-Hoon Ahn   +3 more
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Biodegradation of 4-hydroxybenzoic acid by Phomopsis liquidambari

Applied Soil Ecology, 2011
Abstract Phenolic acid allelochemicals released by decomposing foliage can have negative impacts on growth of plants and microbes in soil. However, these chemicals can potentially be degraded by broad-spectrum endophytic fungi such as, Phomopsis liquidambari (strain B3), which is capable of growing on phenolic 4-hydroxybenzoic acid (4-HBA) as the ...
Yan Chen, Yao Peng, Chuan-Chao Dai, Qun Ju   +3 more
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Dielectric relaxation studies of poly(4-hydroxybenzoic acid) and copolyesters based on 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid

Macromolecules, 1991
The PHBA homopolymer displays a shallow relaxation at low temperature and a stepwise increase in dielectric constant for all frequencies at the high-temperature crystal-to-smectic E transition, while the copolyesters display two solid-phase relaxations with increasing temperature that appear to correlate with localized rotations of the HBA units and ...
Douglass S. Kalika, Do Y. Yoon
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Excited-state proton transfer of 3-hydroxybenzoic acid and 4-hydroxybenzoic acid

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2010
The excited-state proton transfer of 3-hydroxybenzoic acid and 4-hydroxybenzoic acid was studied by time-resolved laser-induced fluorescence spectroscopy with ultra-short laser pulses. The excited-state reactions were identified in aqueous media as a function of the pH value.
Vulpius, D., Geipel, G., Bernhard, G.
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