Showing papers on "Benzoic acid published in 1974"

Disappearances of COOH infrared bands of benzoic acid

Abstract: Infrared spectra of benzoic acid and benzoic acid‐d were obtained in the range of temperatures from liquid nitrogen to liquid helium The C=O stretching band at 1688 cm−1, the strongest absorption band of this compound in the over‐all infrared region at room temperature, decreases in intensity with decreasing temperature and disappears near liquid‐helium temperatures Near this temperature, also lost was the band at 959 cm−1 which has been assigned to the OH out‐of‐plane vibration For the deuterated species both bands at 1689 and 1679 cm−1, which have been interpreted as splitting due to Fermi resonance of the C=O stretching vibration, were lost Close to the positions of these lost bands, alternative bands, which are assignable to the same modes and increase in intensity with decreasing temperature, are found The results support the postulate proposed in our earlier work that two distinct equilibrium configurations of benzoic acid dimer coexist in the crystal

Inhibition by carboxylic acids of an o‐diphenol oxidase from Prunus avium fruits

Abstract: Aromatic carboxylic acids strongly inhibited 4-methylcatechol oxidation by an o-diphenol oxidase extracted from sweet cherry fruits (Prunus avium). Esterification of the acids decreased their inhibitory strength. Inhibitors containing the benzene nucleus showed a greater effectiveness than the corresponding aliphatic and heterocyclic compounds (except 2-naphthalenecarboxylic acid). Similar inhibitory effects were observed by replacing the benzene ring with a highly unsaturated open chain. The inhibitory properties of benzoic acid, cinnamic acid, p-coumaric acid and 3,4-dihydroxybenzoic acid were investigated. It is proposed that the catalytic and inhibitory sites are close together in the enzyme molecule.

Thermodynamics of Ionization of Benzoic Acid and Substituted Benzoic Acids in Relation to the Hammett Equation

Abstract: We have made both ampoule and titration calorimetric measurements leading to ΔH0 of ionization of aqueous benzoic acid at 298 K, and have considered our results in relation to those from several ea...

Chlorophenol and chlorobenzoic acid co-metabolism by different genera of soil bacteria

Abstract: 1. FourPseudomonas strains, anAchromobacter sp., threeNocardia strains,Mycobacterium coeliacum and aBacillus sp., grown on either phenol or benzoic acid as sole carbon source, were tested for co-oxidation of monochlorophenols and monochlorobenzoates respectively. 2. ThePseudomonas spp.,Nocardia spp.,M. coeliacum and theBacillus sp. showed O2-uptakes in the presence ofo-, m- orp-chlorophenol and oxidised them to either 3- or 4-chlorocatechol. 3. Benzoate-grown cells of the threeNocardia spp. and three of the pseudomonads absorbed O2 only in the presence ofm-chlorobenzoate, 4-chlorocatechol being identified as the oxidation product in two cases. One pseudomonad gave some O2-uptake also in presence ofp-chlorobenzoate. 4. Benzoate-grownBacillus cells gave O2-uptakes with eitherm- orp-chlorobenzoate and the former was oxidised to 5-chloro-2,3-dihydroxybenzoic acid via 5-chlorosalicylic acid, thus representing a novel metabolic pathway.

The contribution of solvent drag to the intestinal absorption of the acidic drugs benzoic acid and salicylic acid from the jejunum of the rat.

Abstract: 1 Jejunal loops of anaesthetized rats were perfused with hypotonic, isotonic and hypertonic buffered solutions containing 14C-labelled benzoic acid and salicylic acid at pH 62 and 22 The blood flow of the loop was maintained at an intermediate rate (078–097 ml min−1 g−1) The water net flux was determined by polyethylene glycol as non-absorbable marker and amounted up to +31 or-27 μl min−1 g−1 2 A positive water net flux (leaving the gut lumen) increased the appearance rate of benzoic acid and salicylic acid in the intestinal venous blood by maximally 47 and 41%, a negative water net flux (entering the gut lumen) diminished the appearance rate by 28 and 37% 3 The experimental data were analysed by means of a kinetic model The parameters of the model were the epithelial permeability kF D , the serosal permeability k S F S and the sieving coefficient Φ=1−σ The epithelial permeability was 0115 and 0107 for benzoic acid and salicylic acid at pH 62 and increased to 0163 and 0185 ml min−1 g−1 at pH 22 The serosal permeability was assumed to be identical for neutral and acidic pH and amounted to 0046 and 0112 ml min−1 g−1 indicating that a certain proportion of the absorbed drugs was transferred to the serosal side The sieving coefficient was 292 and 231 at neutral pH and 379 and 356 at acidic pH 4 The main resistance to the absorption of the two drugs is the epithelial membrane, since the effective blood flow and the unstirred layer are not ratelimiting The high sieving coefficient for the two drugs is interpreted as indicating an interaction of drug and water molecules inside the lipid part of the cell membrane (which contains at least 30% water) The electric potential across the gut wall may contribute to the size of the sieving coefficient, if the drug molecules permeate also in the ionized form 5 Using acidic perfusion solutions the epithelial permeability and the sieving coefficient were increased by the factor 13–15 This increase can be explained sufficiently by a facilitated entrance of the unionized drug molecules into the epithelial membrane

Subunit interactions in enzyme catalysis. Kinetic analysis of subunit interactions in the enzyme L-phenylalanine ammonia-lyase.

Abstract: The effects of subunit interactions on the steady-state rate of the reaction catalyzed by the enzymel-phenylalanine ammonia-lyase, have been investigated using the concepts of structural kinetics developed in a previous paper Both theoretical and experimental methods have been proposed, which allow a choice among the possible kinetic models These methods rest on the mathematical analysis of rate data obtained in the presence of substrate analogues, used as inhibitors In the absence of inhibitor, the reciprocal plots exhibit a significant downward curvature If a substrate analogue is present in the reaction medium, the plots can be straight lines, or can even exhibit an upward curvature If vs and vI are the steady-state rate in the absence and in the presence of inhibitor, respectively, the plots (vs/vI)-1 versus inhibitor concentration are either straight lines if the inhibitor is d-phenylalanine, or parabolas if the inhibitor is benzoic acid The detailed analysis of these data as well as previous information obtained on the number of polypeptide chains, suggest that the enzyme is made up of two protomers (Mr 160X103), each protomer consisting of two polypeptide chains: an α chain (Mr 75X103) and a β chain (Mr 85X103) The kinetic data indicate the existence of a hybrid conformation of the enzyme during substrate binding Thus, phenylalanine ammonia-lyase appears to follow neither the classical allosteric model of Monod, nor the simple sequential model of Koshland, but a partially-concerted mechanism of subunit interactions The binding of the substrate induces a conformation change in the corresponding subunit as well as the appearance of a new conformation of the unliganded protomer When d-phenylalanine or benzoic acid are used as inhibitors, no hybrid enzyme · substrate · inhibitor complex is formed It thus appears that the new unliganded conformation, called A′, is still able to bind the substrate, l-phenylalanine, but cannot form a complex with d-phenyl-alanine or benzoid acid The behaviour of the free enzyme appears to be different with regard to D-phenylalanine and benzoic acid The unliganded phenylalanine ammonia-lyasc can bind one molecule of d-phenylalanine only, whereas it can bind two molecules of benzoic acid It thus appears that the binding of d-phenylalanine on a subunit, induces a conformation change of the unliganded subunit, the new conformation (A″) being unable to form a complex with any molecule of inhibitor In the case of benzoic acid, on the other hand, the new conformation of the unliganded protomer is still able to bind an inhibitor molecule

Liquid crystalline dielectrics for electronic components - contg biphenylyl carboxylic acid phenyl ester or benzoic acid biphenylyl ester components

Abstract: Novel biphenylyl carboxylic acid phenyl esters and benzoic acid biphenylyl esters of formula (I) (where X is -COO- or -O-CO- and R1 and R2 are 1-8C alkyl or alkoxy in unbranched chain) are used as components of liq. crystalline dielectrics in electronic components, e.g. electro-optical display matls. Addn. of (I) to other liq. crystalline matls. causes lowering of m. pt. and increase in clarifying point without high rise in viscosity.

Hypolipidemic 4-(monoalkylamino)benzoic acid derivatives

Abstract: 4-(Monoalkylamino)benzoic acids and esters, pharmaceutically acceptable salts thereof, and a method for lowering serum lipids in mammals by administration of said acids, esters and salts; and pharmaceutical compositions thereof.

Exhaustive C-methylation of carboxylic acids by trimethylaluminium: A new route to t-butyl compounds

Abstract: Carboxylic acids are exhaustively C-methylated to t-butyl compounds by excess trimethylaluminium at c. 120o. Benzoic acid for example, gives t-butylbenzene. Similarly methylated are o-fluoro-, o-bromo-, and m-chloro-benzoic acids, 5-chloro-3-phenylsalicylic acid, 1-naphthoic acid, palmitic, oleic and undec-10-enoic acids. Adamantane-1-carboxylic acid gives mostly l-isopropenyladaman- tane, along with some 1-t-butyladamantane. Cinnamic acid gives mainly the allylically rearranged 2-methyl-4-phenylpent-2-ene. Triphenylacetic acid behaves atypically; 1,1,1-triphenylpropan-2-one and 3,3,3-triphenylpropyne result.

Compound‐negative‐ion‐resonant states and threshold‐electron‐excitation spectra of monosubstituted benzene derivatives

Abstract: Threshold‐electron‐excitation (TEE) spectra for fluorobenzene, benzaldehyde, and benzoic acid are presented, discussed, and compared with photoabsorption spectra. The TEE spectra clearly indicate excitation of optically forbidden states. Short‐lived transient‐negative ions have been found to form at low energies (< 2 eV) for nine monosubstituted benzene derivatives. These arise from the quasitrapping of slow electrons in the two lowest unoccupied π orbitals of the benzene‐derivative molecules that, owing to the perturbation introduced by the substituent, are no longer degenerate as in benzene. The positions of these double compound‐negative‐ion resonant states are 1.27, 1.74; 0.61, 1.67; 0.55, 1.88; 0.4, 1.6; 1.30, 2.25; ?, 1.90; 0.66, 1.10; 0.71, 1.12; and 0.63, 1.33 eV for fluorobenzene, phenol, aniline, toluene, N‐methylaniline, anisole, thiophenol, benzaldehyde, and benzoic acid, respectively. These are discussed in terms of the net π‐charge transfer between the substituent and the benzene ring.

Solid/solution interface equilibria for aromatic molecules adsorbed from non-aromatic media. Part 2.—Aromatic carboxylic acids

Abstract: Data have been obtained for benzoic acid, 1-naphthoic acid and 2-naphthoic acid adsorption on the carbon blacks Graphon and Spheron 6, and on the oxides Alcoa C730, Alon C, titanium dioxide and Cab–O–Sil using some or all of the solvents cyclohexane, carbon tetrachloride and cyclohexanone. Individual isotherms were calculated from the composite adsorption isotherms by well-established methods, thus enabling an assessment of the nature of the adsorbed phase. For the carbon blacks and some of the oxide adsorbents, the results are consistent with an adsorbed phase confined to a monolayer with a flat orientation of aromatic molecules; on the more polar oxide adsorbents however there is evidence of perpendicular orientation of the aromatic molecules in some cases, as well as of multilayer adsorption.Thermodynamic quantities for adsorption of the aromatic acids on the carbon blacks, ΔHa, ΔGa and ΔSa are calculated, and an attempt is made to correlate the trends observed with plausible adsorption models as well as with the nature of interactions at the interface.

Plant growth regulants

Abstract: Plant growth regulant effects, such as dwarfing, cessation of terminal growth, increased flower set, increased fruit and pod set, fruiting body abortion, twisting and epinastic responses, etc., may be accomplished on crops such as soybeans, cotton, etc., by application of certain 2-(1,3,4-oxadiazol-2-yl) or 2-(2-oxazolyl) or 2-(1,3,4-thiadiazol-2-yl)benzoic acids, salts and esters, having the formula ##SPC1## Where X is nitrogen or C--R" (R" being hydrogen or methyl), Z is oxygen or sulfur when X is nitrogen, Z is oxygen when X is C--R", R is phenyl or various substituents, and R' is hydrogen or various substituents. An example is 2-(5-phenyl-1,3,4-oxadiazol-2-yl)benzoic acid. The compounds where X is nitrogen and Z is sulfur are new compounds, e.g., 2-(5-phenyl-1,3,4-thiadiazol-2-yl)benzoic acid.

The influence of the solvent on organic reactivity. Part I. Kinetics and mechanism of the reactions of carboxylic acids with diazodiphenylmethane in donor aprotic solvents

Abstract: Apparent second-order rate coefficients have been determined for the reactions at 37 °C of diazodiphenylmethane with benzoic acid in 19 donor aprotic solvents. Values determined for various initial concentrations of acid, c, are analysed in terms of the equation k(obs)=k0+k′c. Reactions of acetic acid and of deuteriated benzoic and acetic acid (PhCO2D and MeCO2D) have also been studied. We conclude that k0 corresponds to the reversible formation of a complex between monomeric acid and diazodiphenylmethane and its subsequent breakdown to products, while k′ corresponds to the reaction of a small amount of highly reactive acid in the form of an open-chain dimer. The effect of a wide range of aprotic solvents on k0 and k′ is interpreted in terms of the following solvent parameters: a function of dielectric constant and one of refractive index, and a measure of solvent nucleophilicity and one of electrophilicity. On including results from an earlier study, multiple linear regression of log k0 on the four parameters gives an excellent correlation for 24 solvents (R= 0·975, s= 0·209). A similar analysis for the log k′ values for ten donor aprotic solvents is less satisfactory. Correlation analysis for log k0 and log k′ values of the reaction in 11 ketones is very unsatisfactory: the hoped-for advantages of considering a homogeneous set of aprotic solvents were thus not realised. Apparent second-order rate coefficients have also been determined for the reactions at 37 °C of diazodiphenylmethane with substituted benzoic acids in seven donor aprotic solvents. Values of k0 and k′, and of the Hammett reaction constant for the two types of rate coefficient are discussed.

The Reaction of Isocyanates with Carboxylic Acids and Thiocarboxylic Acids

Abstract: Thiocarboxylic acids reacted with isocyanates or acyl isocyanates to give the stable addition products. However, similar products obtained from benzoic acid and acyl isocyanates dissociated into their components in solution.

Thiazolyl benzoic acid compounds

Abstract: m-(thiazol-4-yl) benzoic acids substituted in 2- and optionally 5-position of the thiazol ring by lower alkyl, phenylalkyl, phenyl, halo-phenyl, lower alkylphenyl or lower alkoxyphenyl, and on the phenyl ring of the benzoic acid moiety by halogen, hydroxyl, lower alkyl or lower alkoxy. These compounds possess fibrinolytic, platelet stickiness decreasing and antiulcer properties and have an impact on the immunological processes.

Calorimetric Heats of Ionization of Aqueous Benzoic Acid from 5–100 °C and Derived Thermodynamic Quantities

Abstract: We have made calorimetric measurements at 5.0, 12.5, 25.0, 40.0, 50.0, 65.0, 75.0, 85.0, and 100 &([a-z]+);C that lead to values of ΔH0 of ionization of aqueous benzoic acid at each of these temper...

Copolyester prepared by contacting acyloxy benzoic acid with a polyester of ethylene glycol and dicarboxylic acid

Abstract: Disclosed is a copolyester having no substantial amount of either aliphatic to aromatic oxygen linkages or aromatic to aromatic oxygen linkages, the copolyester being comprised of the following divalent radicals: WHEREIN R2 is a carbocyclic aromatic nucleus wherein the chain extending oxygen linkages are coaxial or parallel and are oppositely directed, the range of radical (C) plus radical (D) is from about 30 to about 75 mole percent, based on the total moles of radical (B), radical (C) and radical (D) combined, and the amount of radical (D) is not greater than 30 mole percent, based on the total moles of radical (B), radical (C) and radical (D) combined. The copolyesters of this invention are prepared by a process comprised of two steps. The first step comprises forming a fragmented polyester by acidolysis of a starting polyester with an acyloxy benzoic acid in the presence of a dicarboxylic acid corresponding to radical (A) and a diol corresponding to radical (D). The second step comprises increasing the inherent viscosity of the fragmented polyester to form the copolyester of the invention. The starting polyester is formed from a dicarboxylic acid corresponding to radical (A) and ethylene glycol corresponding to radical (B) and contains a repeating unit composed of radical (A) attached to radical (B). When the acyloxy benzoic acid and starting polyester are contacted in the presence of a dicarboxylic acid corresponding to radical (A), and a diol corresponding to radical (D), acidolysis occurs and a fragmented polyester is formed. The inherent viscosity of the fragmented polyester is then increased to form the copolyester of the invention comprised of radicals (A), (B), (C) and (D). Radical (A) of the copolyester is contributed from the dicarboxylic acid portion of the starting plyester and the quantity of dicarboxylic acid used in preparing the copolyester of the invention, radical (B) of the copolyester is contributed from the ethylene glycol portion of the starting polyester, radical (C) is contributed from the acyloxy benzoic acid, and the aromatic diol contributes radical (D) to the copolyester. Radical (C) will be recognized as the radical remaining after removal of the acyl and hydroxy groups from the acyloxy benzoic acid. The copolyesters of this invention exhibit unobvious mechanical properties.

Heterocyclicamides of hindered 3,5-dialkyl-4-hydroxybenzoic acids and use as light stabilizers in polyolefins

Abstract: Compounds of the formula: ##STR1## WHEREIN R1 and R2 are each branch-chain alkyl of 3 to 8 carbon atoms and -Het is a nitrogen-containing heterocyclic moiety attached to the carbonyl carbon atom through a heterocyclic nitrogen are useful as light stabilizers in polyolefins. They may be prepared (a) by reacting the 3,5-dialkyl-4-hydroxybenzoyl chloride with the appropriate heterocyclic amine in the presence of an acid acceptor or (b) by reacting the corresponding benzoic acid with the appropriate heterocyclic amine in the presence of a carbodiimide as dehydrating agent.