Addition Of Benzoic Acid Research Articles

Degradation of 2,5-dichlorobenzoic acid by Pseudomonas aeruginosa JB2 at low oxygen tensions.

From long-term chemostat experiments, variants of Pseudomonas aeruginosa JB2 were obtained which exhibited altered properties with respect to the metabolism of 2,5-dichlorobenzoic acid (2,5-DBA). Thus, unlike the original strain JB2-WT, strain JB2-var1 is able to grow in continuous culture on 2,5-DBA as the sole limiting carbon and energy source. Yet, at a dilution rate of 0.07 h-1 and a dissolved oxygen concentration of < or = 12 microM, even with this strain no steady states with 2,5-DBA alone could be established in continuous cultures. Yet another strain was obtained after prolonged continuous growth of JB2-var1 in the chemostat. It has improved 2,5-DBA degrading capabilities which become apparent only during growth in continuous culture: a lower apparent Km for 2,5-DBA and lowered steady-state residual concentrations of 2,5 DBA. Although with this strain steady states were obtained at oxygen concentrations as low as 11 microM, at further lowered concentrations this was no longer possible. In C-limited continuous cultures of JB2-var1 or JB2-var2, addition of benzoic acid (BA) to the feed reduced the amounts of 2,5-DBA degraded, which was most apparent at low oxygen concentrations (< 30 microM). At higher dissolved oxygen concentrations the addition of BA resulted in increasing cell-densities but did not affect the residual steady state concentration of 2,5-DBA. Indeed, whole cell suspensions from chemostat cultures grown on BA plus 2,5-DBA did show a lower apparent affinity for 2,5-DBA than those from cultures grown on 2,5-DBA alone.(ABSTRACT TRUNCATED AT 250 WORDS)

A spin-spin relaxation rate investigation of the gelatin ferrous sulphate NMR dosimeter

Spin-spin NMR relaxation rate in the ferrous sulphate gelatin dosimeter has been studied in terms of pH, gelatin concentration, the addition of benzoic acid, and sample size. It is demonstrated that R2 is more sensitive to changes in Fe3+ ion concentration than R1 when measuring at frequencies of 64 and 100 MHz. pH has an important effect on dose response curves, and oxygen depletion occurs significantly more rapidly in FeSO4 gelatin than in the liquid FeSO4, resulting in a saturation dose of approximately 80 Gy at depths greater than approximately 3 mm in phantom. The concentration of gelatin can be increased to 12% by weight, and the dosimeter will continue to exhibit a linear dose response. Sensitivity is maintained at higher gel concentrations by pH compensation. Addition of low-concentration benzoic acid to the system does not alter the dose response of the gelatin FeSO4 system. Finally, spontaneous oxidation of Fe2+ ions does not significantly alter the shape of dose response curves but does result in increases in R2 by up to 4% per day.

Preparation and Structure of the Novel Dinuclear Vanadium(III) Complex Bridged by an Alkoxo Group and a Carboxylato Group

Abstract The reaction of 1,3-diamino-2-propanol-N,N,N′,N′-tetraacetate (dpot) with VCl3 followed by the addition of benzoic acid (Hbza) or hydroxybenzoic acid (Hhbza) has yielded the dinuclear vanadium(III) complex, [V2(dpot)(bza or hbza)(H2O)2], bridged by both a deprotonated alkoxo group of dpot and a carboxylato group of bza or hbza.

ChemInform Abstract: Activation of 1‐Alkynes at Tripodal (Polyphosphine)rhodium Systems. Regioselective Synthesis of Enol Esters from 1‐Alkynes and Carboxylic Acids Catalyzed by Rhodium(I) Monohydrides.

AbstractRegioselective formation of 2‐(benzoyloxy)propene (III) results from the addition of benzoic acid (I) to propyne (II) in the presence of the trigonal‐bipyramidal Rh(I) monohydrides LRhH (L: E(CH2CH2PPh2)3, E: P, N).

Activation of 1-alkynes at tripodal (polyphosphine)rhodium systems. Regioselective synthesis of enol esters from 1-alkynes and carboxylic acids catalyzed by rhodium(I) monohydrides

Regioselective formation of 2-(benzoyloxy)propene results from the addition of benzoic acid to propyne in the presence of the trigonal-bipyramidal Rh(I) monohydrides [(PPh 3 )RhH] (1) and [(NP 3 )RhH] (2, PP 3 =P(CH 2 CH 2 PPh 2 ) 3 , NP 3 =N(CH 2 CH 2 PPh 2 ) 3 ). The reactions are catalytic under relatively mild conditions (catalyst to substrate ratio 1:100, toluene, 100 o C). A detailed experimental study on the reactions of 1 and 2 with carboxylic acids, 1-alkynes, or carboxylic acid/1-alkyne mixtures has allowed us to draw a catalysis cycle involving the 16-electron fragments [(L)Rh] + as catalysts (L=PP 3 , NP 3 ). The catalytic behavior of the precursors 1 and 2 has been compared and contrasted with those of the isostructural and isoelectronic derivatives [(L)Rh(C≡CPh), [(L)RhCl], and [(PP 3 )RhMe]. The novel vinylphosphonium complex [(Ph 2 PCH 2 CH 2 ) 2 P(CH 2 CH 2 PPh 2 )Rh{C=C(H)Ph}(O 2 CPh) has been synthesized and fully characterized by IR and 1 H and 34 P{ 1 H} NMR techniques

Effect of radical scavengers on canine peripheral blood mononuclear lymphocyte-mediated cytotoxicity and production of active oxygen.

Production of active oxygen by canine peripheral blood mononuclear lymphocytes (PBLs) from beagle dog was examined by luminol-dependent chemiluminescence production. The canine PBLs rapidly produced the active oxygen in parallel with the number of cells when PBLs were cocultured with canine leukemia-derived CL-1 cells as target cells. Cytolysis of the target cells and active oxygen production were inhibited linearly by the addition of benzoic acid and n-propyl gallate as hydroxyl radical scavenger. However, superoxide dismutase and tiron which are scavengers of superoxide anion did not inhibit the cytotoxicity so much at low concentrations that inhibited the induction of luminol-dependent chemiluminescence. These results suggest that hydroxyl radical production by stimulated PBLs might be playing a major role of cytotoxic action in the case of canine system.

Functionalization of polysiloxanes by esterification of pendant glycidic groups: Catalyzed reaction in N, N-dimethylformamide

A kinetic study of the addition of benzoic acid to polysiloxane-bound groups, carried out in N, N-dimethylformamide (DMF) with tetrabutylammonium bromide as catalyst, is reported. It has been found that, at a fixed concentration in catalyst (0–10 mol%), the esterification obeys a simple first order kinetic law with respect to the concentration of epoxy groups. A complex mechanism is however proposed to account for the non-linear dependence of the variation of the observed first order rate constant with the catalyst concentration. Some examples of preparative reactions carried out on polysiloxanes having different molecular weights and epoxy group contents are given to indicate the synthetic interest and the scope of this functionalization performed in DMF.

Modification au deuxième degré de polymères époxydés, 2. Addition de l'acide benzoïque sur polyènes époxydés

AbstractThe addition of benzoic acid to the oxirane ring of epoxidized polymers of dienes is limited by side reactions which are promoted by increase of time, temperature, or epoxide concentration. Only high [Acid]/[Epoxide] ratios afford good yields of modification of the epoxidized polymers.

Determination of anthranilate, 3-hydroxyanthranilate and 2,3-dihydroxybenzoate in the enzyme assay of anthranilate hydroxylase by thin-layer and high-performance liquid chromatography

A high-peformance liquid chromatography technique using UV detection is reported for the assay of anthranilate 2,3-dioxygenase (deaminating) activity. The substrate anthranilate, the main product 2,3-dihydroxybenzoate and the by-product 3-hydroxyanthranilate are determined quantitatively in the presence of biolgical material. After addition of benzoic acid as internal standard, the substances of interest are separated isocratically on a reversed-hase C 18 column with a detection sesitivity of 0.5 nmol and retention times of 3.5–10 min. A thin-layer chromatographic and fluorimetric method is also described.

Modification au deuxième degré de polymères époxydés, 1. Etude sur molécules modèles des polyalcadiènes

AbstractThe addition of benzoic acid to the oxirane ring of model compounds for epoxidized polymers of dienes was studied. A convenient reaction rate was observed for temperatures of about 100°C. It was found that the addition reaction can be catalysed by basic compounds. Kinetic studies showed the influence of solvent nature, of concentration of reagents, of catalysts, and of the epoxide structure. The reactivities of various acids showing particular properties (drugs, UV‐absorbers, herbicides) were investigated.

Rapid synthesis of oligodeoxyribonucleotides III. Effect of added carboxylate ion on the efficiency of internucleotide bond formation. Solid-phase synthesis of the dodecanucleotide, d(pT-A-A-C-T-G-C-T-C-A-C-T)

In solid-phase oligodeoxyribonucleotide synthesis the addition of benzoic acid to internucleotide phosphodiester bond-forming reactions lowers coupling yields by far greater amount than anticipated on a simple nucleotide-carboxylate molar ratio. High coupling yields were consistently obtained in synthesis of the dodecanucleotide, d(pT-A-A-C-T-G-C-T-C-A-C-T), using rigorously purified nucleotide starting materials.

The effect of feeding on the hippuric acid content of cow’s urine

The urinary hippuric acid contents of dairy cows on a purified, proteinfree feed (0-feed, 0-cows), as well as the effect of benzoic acid and aromatic amino acid supplements, and silage and hay supplements, on the urinary hippuric acid content, were followed in the present study. The hippuric acid contents of the urine of 0-cows were compared with those of a cow on low-protein, urea-rich feed containing hemicellulose (ULP-cow). and of normally-fed cows (NorP-cows). The urinary hippuric acid content of the 0-cows varied between 0.1 and 0.6g/l (n = 8). The proportion of hippuric acid nitrogen of the total urinary nitrogen was 0.2—0.9 %. The presence of hippuric acid in the urine of the 0-cows indicates an endogenic hippuric acid production within the cow. 0-feed is deficient in all exogenic precursors of benzoic acid. Addition of benzoic acid to the feed of 0-cow caused temporary rise in the hippuric acid contents of the urine, of aromatic amino acids the addition of tyrosine, besides benzoic acid, raised the urinary hippuric acid content by a highly significant amount. The urinary hippuric acid content of the ULP-cow was on average 6.7 g/l (n = 42) and the proportion of hippuric acid on the total urinary nitrogen 5.2 %. The urinary hippuric acid contents of the NorP-cows were on average 11.9 g/l (n = 14), and the proportion of hippuric acid nitrogen of the total urinary nitrogen 10.7%. The difference in the urinary hippuric acid contents with 0- and NorP-cows is significant, as is also the difference in the proportions of hippuric acid nitrogen of the total urinary nitrogen with these cows. The difference in the hippuric acid contents of 0- and ULP-cows is also significant (P &lt; 0.01). The same regards ULP- and NorP-cows (P &lt; 0.01).

Thermochemical transformations of compounds modelling aromatic polyamide units

A kinetic study has been made of CO and CO 2 evolution during the degradation of benzanilide and N-methylbenzanilide under vacuum in the presence of water. In addition the degradation of benzanilide in the presence of benzoic acid and aniline has been investigated. It is shown that the decomposition of N-methylbenzalinide under vacuum and in the presence of water proceeds by a homolytic mechanism. The degradation of benzanilide in the presence of water takes place by a hydrolytic mechanism. The addition of benzoic acid and aniline has no catalytic effect on the degradation of benzanilide.

Effect of benzoate on microbial decomposition of fulvic acids in Tjeukemeer (the Netherlands)

The addition of benzoic acid to water from Tjeukemeer stimulated bacterial growth and decreased both the fluorescence and the color of the water, indicating disappearance of fulvic acids. This stimulation of bacterial growth is shown to result most likely from a priming effect of benzoic acid on the slow microbial decomposition of fulvic acid.During growth of an Arthrobacter from the lake on benzoic acid in the presence of fulvic acid, fulvic acid of relatively small molecular size was formed from fulvic acid of relatively large molecular size, suggesting that microbial activity may play a role in the seasonal fluctuations in the molecular size distribution of fulvic acids in Tjeukemeer.

ChemInform Abstract: RETARDATION OF AUTOXIDATION IN THE PRESENCE OF WATER, ALCOHOLS AND CARBOXYLIC ACIDS

AbstractDie Oxidation von Alkoholen (insbesondere 1‐Phenyl‐äthanol, aber auch z.B. Benzylalkohol, Isopropanol), α‐substituierten Toluolen (wie Äthyl‐, Isopropyl‐, 2‐Chlor‐äthyl‐benzol, Diphenylmethan, Dibenzyläther) und einigen weiteren orga‐.

Retardation of Autoxidation in the Presence of Water, Alcohols and Carboxylic Acids

Abstract The oxidation of alcohols and α-substituted toluenes in water, methanol and acetic acid was studied at 60–70 °C in the presence of 0.040 M AIBN. The rate of oxidation of alcohol, kp/(2kt)1⁄2, considerably increases when the alcohol is diluted with an inert solvent. The rate remarkably decreases with the addition of water, methanol or various carboxylic acids. However in the presence of tetralyl hydroperoxide, viz., when the hydroperoxyl radical is replaced by the tetralyl peroxyl radical, no further inhibition effect due to water, methanol or carboxylic acids is observed. The rate of oxidation of 1,4-cyclohexadiene decreases with the addition of water or acetic acid. However in the presence of 0.20 M tetralyl hydroperoxide, no further inhibition effect is observed. The rate of oxidation of 1-phenylethanol decreases with the addition of benzoic acid but not with that of methylbenzoate. The rate of oxidation of (2-chloroethyl) benzene, ethylbenzene and isopropylbenzene does not decrease with the addition of 0.224 M acetic acid, but that of N,N-dimethylbenzylamine, N,N-diethylbenzylamine, benzyl alcohol, 1-phenylethanol and methyl benzyl ether decreases. It is concluded that hydroperoxyl and alkylperoxyl radicals with α-substituents such as hydroxyl, carbonyl, alkoxyl or amino groups undergo deactivation due to hydrogen bonding with water, alcohols and carboxylic acids.

Mechanism of Ester Formation from Benzaldehyde over Solid Base Catalysts

The esterification of b6nzaldehyde has been studiedi over solid NaOH, NaOH-SiO2, A120s, SrO2, BaOz, SrO and CaO. The catalytic'activity was found not. only to closely relate with the basic properties, but also to relate, with the acidic proPerties (Fig., 6). lt was o. bserv. ed that two d-hYdrogens of benzyl groups of benzyl benzoate (major product) and benzyl alcohol (miner product) produced by the esterification of ibenzaldehyde-a-at were deuterat. ed. and t-hqt there The catalytic activity was was no hydrogen isotope effect(kH/kD=1, o, 2)(Figs, 1and 2), decreased by the addition of benzoic acid or phenol, but not by. the addition of benzene or cyclohexane' (Figs.3, 4 and 5). Thg amount of benzylE alcohol formed was increased by the addition of aliphatic alcohols (Fig.4).On the basi's of the observed results, it has been concluded that the aetive sites for the esterification are metal bezylates and those for the formation of metal benzylate consist of both basic sites (surface OZ) and Lewis acid sites (Ca2 etc. ). The mechanism of the esterification has been N@discussed in detail and 'c'ompared, with those of Cannizzaro and Tishchenko reaction in homogeneous system,

Non-ionic surface-active agents. Part VII. Solubility of benzoic acid in aqueous solutions of some monododecyl polyoxyalkanols

Further study has been made of the solubility of benzoic acid in aqueous solutions of polyoxyalkanols of general formula (C12H25·[OCH2·CH2]mOH)(I) where m= 2–12. The surfactants were prepared by methods giving materials of specific hydrophilic chain length and this was confirmed by gas chromatography. Lower members of the series (m= 2–6) had poor solubilising powers since addition of benzoic acid caused the aqueous solution to separate into two liquid phases, probably because the lower consolute temperature of the systems was depressed below 20°. Higher members (m= 7–12) were more effective and solid benzoic acid separated at the solubility limit. The results are compared with two models which have been used to describe the solvent properties of micellar solutions of non-ionic surfactants. It is concluded that the partition model is more satisfactory than the one in which benzoic acid is adsorbed at the interface of the ‘core-and-capsule’ within the micelles.

DEVELOPMENT AND EVALUATION OF AN HPLC-DAD METHOD FOR DETERMINATION OF BENZOIC ACID IN TOMATO SAUCE AND KETCHUP

According to Directive 95/2/EC dated on 20.02.1995 of the European Union (EU), the benzoic acid belongs to the preservatives allowed conditionally, and the quantity of benzoic acid added to foods is restricted by upper limits. There are many methods available for the analysis of benzoic acid in foods and the decision as to what method should be used depends on the matrix to be analyzed. Most of the methods are for liquids and further method development may be required to adapt these methods to be applicable for all matrices. &#x0D; As all tomato sauce and ketchup available on our market are made with benzoic acid addition and their consumption is high, the operational parameters leading to the development of a method for the analysis of benzoic acid within tomato sauce and ketchup have been studied, the technique used is the high performance liquid chromatography together with diode array detection (DAD). It has been tried to validate the analysis method settled, in terms of sensitivity, linearity range, reproducibility, repeatability and recovery. The method provides a stable retention time and a limit of detection of 0.8 mg/kg in the sample at a signal to noise ratio of 3.&#x0D; For analysis, the sample is extracted or diluted with water, and the solution of the sample with the benzoic acid is purified by an extraction with Carrez reagents. The benzoic acid in the sample test solution is separated on a C18 chromatography column in a reversed phase, detected by absorbance at the wavelength of 217 nm and quantified with a calibration graph.

WHITFIELD'S OINTMENT

To the Editor:— I was somewhat surprised to see, in a discussion on tinea cruris in the February issue of theArchives, page 225, the opinion stated that Whitfield's ointment was in action a salicylic acid ointment and that the benzoic acid was inactive. The observers said the salicylic acid alone was effective, and apparently based their opinions on its use without the addition of benzoic acid. I have not claimed that the formula used by me was the most powerful possible, but merely that it was on the whole effective and certainly cleanly. My first experiments were carried out with 5 per cent. benzoic acid, without salicylic acid and I found, as I think other observers will also find, that in tinea of parts supplied with a thin horny layer the eruption disappeared in four or five days. The salicylic acid was afterward added, especially for the tinea of