P-Hydroxybenzoic acid methyl ester

Fig. 5 Comparison between the release constants of p-hydroxybenzoic acid methyl ester from porous and non-porous silica support in an acidic dissolution fluid. (From Ref...

Srcic, S. Rupprecht, H. Mrhar, A. Karba, R. Chemiadsor-bates of p-hydroxybenzoic acid methyl ester on silica as a new type of pro-drug. III. Modelling and simulation of drug release from chemiadsorbates to acid aqueous solution. Int. J. Pharm. 1991, 73, 221-229. 

SYNS ABIOL ASEPTOFORM MASEPTOL METHYLBEN METHYL CHEMOSEPT METHYL ESTER of p-HYDROXYBENZOIC ACID METHYL p-HYDROXYBENZOATE METHYL p-OXYBENZOATE... 

CAS 99-76-3 EINECS/ELINCS 202-785-7 FEMA 2710 INS218 E218 Synonyms 4-Hydroxybenzoic acid, methyl ester Methyl 4-hydroxybenzoate Methyl p-hydroxybenzoate Methyl p-oxybenzoate ... 

Phenoxyethyl 2-methyl propanoate. See Phenoxyethyl isobutyrate 2-Phenoxyethyl 2-methyl-2-propenoate. See 2-Phenoxyethyl methacrylate 2-Phenoxyethyl 2-methylpropionate. See Phenoxyethyl isobutyrate Phenoxyethylparaben CAS 55468-88-7 EINECS/ELINCS 259-654-2 Synonyms p-Hydroxybenzoic acid, phenoxyethyl ester 2-Phenoxyethyl p-hydroxybenzoate... 

Synonyms 4-Hydroxybenzoic acid, methyl ester, sodium salt Methylparaben sodium Methylparaben sodium salt Sodium 4-(methoxycarbonyl) phenolate Sodium methyl 4-hydro xybenzoate Sodium methyl p-hydroxybenzoate Definition Sodium salt of methylparaben Empiricai CsHyNaOs Properties Wh. powd. freely sol. in water sparingly sol. in alcohol insol. in fixed oils m.w. 174.14 pH 9.5-10.5 (1 in 1000)... 

C12 to C20, primarily Ci6 to ( is), used as surface lubricants in the manufacture of food-contact articles. The method, which uses ethyl palmitate (Eastman Chemicals No. 1575 Red Label) as an internal standard, has been validated at 200 ppm total FAME [185]. Other FAME standards (methyl palmitate, methyl stearate, methyl oleate, methyl linoleate and methyl linolenate) are available (Applied Science Laboratories) [116], Worked out examples of additive determinations are given in the Food Additives Analytical Manual [116], which also describes a great many of indirect food additives, such as BHA, BHT, TBHQ, l-chloro-2-propanol, DLTDP, fatty acid methyl esters, w-heptyl-p-hydroxybenzoate, propyl-gallate, sodium benzoate, sodium stearoyl-2-lactylate, sorbitol and phenolic antioxidants. EPA methods 606 and 8060 describe the CGC separation of phthalate esters (direct injection) (cf. Figure 4.2). 

These esters of p-hydroxybenzoic acid have been used primarily to prevent growth of molds but in higher concentrations possess some weak antibacterial activity. Their effective use is limited by low aqueous solubility and by reports of stinging and burning sensations related to their use in the eye. They bind to a number of nonionic surfactants and polymers, thereby reducing their bioactivity. They are used in combination, with the methyl ester at 0.03-0.1% and the propyl ester at 0.01-0.02%. Parabens have also been shown to promote corneal absorption [140]. 

Methyl 4-hydroxy benzoate 4-hydroxy benzoic acid, methyl ester methyl p-hydroxybenzoate... 

More compounds have been identified in the neutral oxygen methyl ester fraction, shown in Figure 9, than in either the alkaline or acidic oxygen reactions. In addition to the products found in the alkaline oxygen reaction, the methyl ether ester of p-hydroxybenzoic acid and the methyl ester of mellitic acid are present. The acidic oxygen methyl ester fraction, also shown in Figure 9, qualitatively resembles the alkaline oxygen reaction. All the acids found in this latter reaction, except benzoic, are found in this fraction. The methyl ether ester of dehydrodivanillic acid or the methyl... 

Among the derivates of HBAs, further compounds have been identified. GUntert et al. (1986) identified ethyl esters of vanillic acid and p-hydroxybenzoic acid, and methyl esters of vanillic acid and protocatechuic acid. Ethyl esters of protocatechuic acid and vanillic acid, as well as the glucose ester of vanillic acid, were isolated from a German Riesling wine (Baderschneider and Winterhalter 2001). Analytically, HBA are mostly determined as trimethylsilane derivatives by using... 

METHYLENIUM CERULEUM see BJI250 METHYL-18-EPIRESERPATE METHYL ETHER HYDROCHLORIDE see MQR200 METHYL ESTER of p-HYDROXYBENZOIC ACID see... 

Acidic preservatives are the most widely used for oral preparations, such as the p-Hydroxybenzoic acid esters and salts of benzoic acid. These are adequately soluble in aqueous systems and possess both antifungal and antibacterial properties. Methyl and propyl p-hydroxybenzoic acid are often used together in a 10 1 ratio. Concomitant use of multiple esters makes possible a higher total preservative concentration owing to the independent solubilities of each and, according to some researchers, maximizes the antimicrobial effect. 

Main components During fermentation, vanillin (up to app. 2.5%) is formed from the odourless glucovanillin by enzymatic hydrolysis. Its aroma is rounded-off and modified by p-hydroxybenzoic acid, p-hydroxybenzaldehyde, p-hydroxybenzyl methyl ether, vanillyl alcohol, vanillic acid, cinnamic acid ester and various other trace constituents [291, 292], Also the resins, gums, amino acids and other organic acids contribute to the typical flavour of the cured beans [293[. For further constituents and characterisations of fruits from different growing areas see [294[. 

Parabens [Napp]. TM for the methyl, propyl, butyl, and ethyl esters of p-hydroxybenzoic acid. Antimicrobial agents for foods and pharmaceuticals. Approved by FDA as GRAS. 

The alkyl esters (methyl, ethyl, and propyl) of p-hydroxybenzoic acid (the parabens) are widely used for their antifungal properties. The preservative effect of parabens tends to increase with increasing molecular mass. The methyl ester appears to be more effective against molds, whereas the propyl ester is more effective against yeasts (favored for oils and fats, for solubility reasons) (Gonzalez, Gallego, and Valcarcel, 1998). 

CAS 94-18-8 EINECS/ELINCS 202-311-9 Synonyms Benzoic acid, 4-hydroxy-, phenyl methyl ester Benzyl 4-hydroxybenzoate Benzyl p-hydroxybenzoate Phenylmethyl 4-hydroxybenzoate Definition Ester of benzyl alcohol and p-hydroxybenzoic acid Empirical C14H12O3 Toxicology TSCA listed Uses Preservative, bactericide, fungicide for foods, pharmaceuticals, industrial applies. antimicrobial in cosmetics Regulatory BP compliance Manuf./Distrib. Aldrich http //www.sigma-aldrich.com-, Alfa Aesar http //www.aifa.com-, Archimica Inc http //www.archimica.com-. 

CAS 4247-02-3 EINECS/ELINCS 224-208-8 Synonyms 4-Hydroxybenzoic acid, 2-methyl propyl ester Isobutyl 4-hydroxybenzoate Isobutyl p-hydroxybenzoate Isobutyl parahydroxybenzoate Definition Ester of isobutyl alcohol and p-hydroxybenzoic acid Empirical C11H14O3 Properties M.w. 194.25... 

Gentisic acid glycosides act as leaf movement factors in Mimosa species (E 2.2). Gallic acid is an inhibitor of flowering in Kalanchoe blossfeldiana (E 2.2). Benzoic acid, p-hydroxybenzoic acid as well as protocatechuic acid methyl and ethyl esters are secreted from the pygidial glands of water beetles as antiseptics and feeding deterrents (E 5.1). 

Benzoic acid derivatives Benzoic acid, p-hydroxybenzoic acid, protocatechuic acid methyl and ethyl esters, hydroquinone (D 22.2.5) Hydroquinone (D 22.2.5), H2O2 Secreted from the pygidial glands of the water beetles Dytiscus sp., feeding deterrent, antiseptic Synthesized in glands of the bombardier beetles Brachynus sp. (Fig. 338)... 

As p-hydroxybenzoic acid esters present a relatively high pKa value (approx. 8.5), their antimicrobial action is less dependent on the pH value of the type of food to be preserved. In this respect they are superior to the organic preservative acids. Unfavourably, as in the case of phenol, p-hydroxybenzoic acid esters may be linked to some extent to proteins, emulsifiers or other food components on account of their phenolic hydroxylic-group and thus be inactivated. The antimicrobial action of the p-hydroxybenzoic acid esters is proportional to the alkyl chain length. Thus the antimicrobial action of the methyl ester is some 3 to 4 times, that of the ethyl ester some 5 to 8 times, that of the propyl ester about 25 times as powerful as phenol (Thompson, 1994). However, superimposed on this effect may be the water solubility of the esters, which is inversely proportional to the alkyl chain length. Since the activity spectra of the individual p-hydroxybenzoic acid esters are different, the application of mixtures can be profitable. 

Applications. In many countries the methyl, ethyl and n-propyl esters of p-hydroxybenzoic acid, as well as their sodium salts, are permitted for preservation of some foods. The maximum permissible quantity is around 0.1%. In the USA methyl- and propyl-paraben are considered GRAS. The maximum permissible quantity is 0.1%. Their main field of use is not food preservation but the preservation of pharmaceutical and cosmetic fat emulsions. The usage of the butyl ester is not allowed in food applications. 

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