N-Propyl p-hydroxybenzoate

Thiourea, methyl p-hydroxy-benzoate, ethyl p-hydroxybenzoate, n-propyl p-hydroxybenzoate, n-butyl p-hydroxybenzoate, propranolol, biphenyl, dibucaine... 

Retention time 4.8 (hydrocortisone), 8.4 (hydrocortisone succinate) Internal standlard n-propyl p-hydroxybenzoate (7.2)... 

Simultaneous degradation products, methyl p-hydroxyhenzoate, sulfamethoxazole Noninterfering n-propyl p-hydroxybenzoate... 

Propyl 4-hydroxybenzoate n-Propyl p-hydroxybenzoate Propyl p-hydroxybenzoate. See Propylparaben... 

CAS 94-13-3 EINECS/ELINCS 202-307-7 FEMA 2951 INS216 E216 Synonyms 4-Hydroxybenzoic acid, propyl ester p-Hydroxybenzoic acid, propyl ester p-Hydroxypropyl benzoate Propyl 4-hydroxybenzoate n-Propyl p-hydroxybenzoate Propyl p-hydroxybenzoate Propyl parahydroxybenzoate Propyl parasept Classification Organic ester Definition Ester of n-propyl alcohol and p-hydroxybenzoic acid Empirical C10H12O3... 

Propyl 4-hydroxybenzoate n-Propyl p-hydroxybenzoate Propyl p-hydroxyben-zoate. See Propylparaben Propylic alcohol. See Propyl alcohol Propylmethanol. See Butyl alcohol Propyl 9-octadecenoate. See Propyl oleate Propyl oleate CAS 111-59-1... 

A paired-ion, reversed-phase high-performance liquid chromatographic method was developed for the simultaneous determination of sweeteners (dulcin, saccharin-Na, and acesulfame-K), preservatives (sodium dehydroacetate, SA, salicyclic acid, BA, succinic acid, methyl-para-hydroxybenzoic acid, ethyl-para-hydroxybenzoic acid, n-propyl-para-hydroxybenzoic acid, n-butyl-para-hydroxybenzoic acid, and isobutyl-para-hydroxybenzoic acid), and antioxidants (3-tertiary-butyl-4-hydroxyanisole and tertiary-butyl-hydroquinone). A mobile phase of acetonitrile-50 ml aqueous tr-hydroxyisobutyric acid solution (pH 4.5) (2.2 3.4 or 2.4 3.6, v/v) containing 2.5 mM hexadecyltrimethylammonium bromide and a Clg column with a flow rate of 1.0 ml/min and detection at 233 nm were used. This method was found to be very reproducible detection limits ranged from 0.15 to 3.00 p,g. The retention factor (k) of each additive could be affected by the concentrations of hexadecyltrimethylammonium bromide and a-hydroxyisobu-tyric acid and the pH and ratio of mobile phase. The presence of additives in dried roast beef and sugared fruit was determined. The method is suitable for routine analysis of additives in food samples (81). 

SYNS ASEPTOFORM P BETACIDE P BONOMOLD OP 4-HYDROXYBENZOIC ACID PROPYL ESTER p-HYDROXYBENZOIC ACID PROPYL ESTER NIPASOL p-OXYBENZOESAEUREPRO-PYLESTER (GERMAN) PARABEN PARj SEPT PASEPTOL PRESERVAL P PROPYL p-HYDROXY-BENZOATE n-PROP X p-HYDROXYBENZOATE PROPYLPARABEN (FCC) PROPYLPARASEPT PROTABEN P TEGOSEPT P... 

A gas chromatographic method may be employed for analysis for both benzoic acid and sorbic acid in food, as described in AOAC method 983.16. The acids are extracted from an acidified aqueous homogenized food sample into ether. The acids are then extracted from the ether solution into aqueous alkali, and after acidification they are re-extracted into dichloromethane. Treatment of the residue with N-methyl-N-trimethylsilyltrifluoroacetamide converts the benzoic and sorbic acids into trimethylsilyl esters. These esters are then analyzed with a glass column packed with a support coated with OV-1, in a temperature programmed analysis. Phenylacetic and caproic acids are used as internal standards for benzoic and sorbic acids, respectively. An LC method has also been described for analysis of benzoic acid with simultaneous determination of sorbic acid, and methyl, ethyl, propyl, and butyl p-hydroxybenzoates. The preservatives were extracted from meat or seasonings with 70% ethanol, and analyzed by reversed-phase LC using a Cig stationary phase with a linear gradient from 10 to 70% methanol in 1.5% aqueous ammonium acetate and 1.5% aqueous acetic acid. 

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. 

The most common method for the preparation of PCPP is the macromolecular substitution of the polydichlorophosphazene precursor [37] (see Section 1.1). This requires the use of protecting group chemistry, as it is well known that free acid groups lead to skeletal breakdown reactions. Propylparaben, the n-propyl ester of p-hydroxybenzoic acid has been most widely used for this, with subsequent deprotection of the propyl ester by hydrolysis under basic conditions. The requirement for complete macromolecular reactions has been addressed and structurally homogeneous, fully deprotected PCPP can be attained with the correct structure on relatively large (2 kg) scales [21, 26, 38, 39]. 

Detinhion Ester of n-propyl alcohol and p-hydroxybenzoic acid... 

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