Showing papers on "Acetic acid published in 1971"

Characteristics of Acid Reaction in Limestone Formations

Abstract: A kinetic model for the reaction of hydrochloric acid with limestone has been determined. Reaction order and rate constant for this model were calculated from experiments where acid reacted with a single calcium carbonate plate. Experiments were performed so that acid flow past the plate and mass transfer rate to the rock surface could be calculated theoretically. The resulting model, therefore, accurately represents the acid reaction process at the rock surface and is independent of mass-transfer rate. Combination of this model with existing theory allows prediction of acid reaction during acid-fracturing operations. A model for acid reaction in wormholes created during matrix acidization treatments is presented along with data for reaction of hydrochloric, formic, and acetic acids in a wormhole. Factors limiting stimulation in acid fracturing or matrix acidizing treatments are discussed. (27 refs.)

Autoxidation products of 2,4-decadienal

Abstract: 2,4-Decadienal was autoxidized by purging a purified sample with oxygen. An analysis of the autoxidative degradation products was made with tandem gas chromatography-mass spectrometry. Additional information was obtained from the determination of the melting point of the dinitrophenylhydrazone derivatives and IR absorbency data. Pentane, furan, ethanal, hexanal, acrolein, butenal, 2-heptenal, 2-octenal, benzaldehyde, glyoxal,trans-2-buten-1,4-dial, acetic acid, hexanoic acid, 2-octenoic acid, 2,4-decadienoic acid and benzene were identified.

Palladium-gold catalyst

Abstract: AN IMPROVED CATALYST FOR THE CATALYTIC, VAPOR PHASE PRODUCTION OF VINYL ACETATE FROM ETHYLENE, ACETIC ACID AND MOLECULAR OXYGEN SI SHOWN. A CATALYST FOR THE SYNTHESIS REACTION COMPRISING METALIC PALLADIUM AND AN ALKALI META ACETATE OR FORMATE SUPPORTED ON A CARRIER IS ACTIVATED BY INCLUDING METALLIC GOLD THEREIN. A PREFERRED CATALYST COMPOSITION WHICH SHOWS SUBSTANTIALLY IMPROVED OPERATING CHARACTERISTICS INCLUDES METALLIC PALLADIUM, AN ALKALI METAL ACETATE AND METALLIC GOLD. ANOTHER PREFERRED CATALYST COMPOSITION INCLUDES A LOW MELTING MIXTURE OF AT LEAST TWO ALKALI METAL ACETATES.

Stereochemistry of si‐Citrate Synthase and ATP‐Citrate‐Lyase Reactions

Abstract: 1 A new synthesis of R- and S-acetic acid (R- and S-[2H1, 3H1]acetate) is described. 2 R-Acetic acid after conversion into citrate on si-citrate synthase and cleavage of the citrate with citrate lyase regenerates an acetate which is still predominantly R. 3 S-Acetic acid when put through the same sequence yields acetic acid which is predominantly S. 4 Essentially the same results as in (2) and (3) are obtained when ATP-citrate lyase is substituted for citrate lyase. 5 The conclusion is drawn that on si-citrate synthase, the replacement of hydrogen by oxaloacetic acid proceeds with inversion of configuration at the methyl group. 6 It also follows that ATP-citrate lyase, like citrate lyase, cleaves citrate with inversion of configuration. 7 It is further deduced that there is a normal intramolecular deuterium-isotope effect, with respect to the chiral-methyl group, in the condensation of chiral acetate with oxaloacetate on si-citrate synthase.

Ultrasonic Investigation of Acetic Acid Hydrogen Bond Formation. II Acetic Acid–Water Solutions

Abstract: Ultrasonic absorption has been measured in acetic acid–water mixtures in the range 3.6 molar acetic acid to 17.38 molar (glacial). The frequency range covered was 0.5–150 MHz and measurements were made at 18, 25, 35, and 50°C. Measurements were also made with added H+ and OAc− ions. The data for every solution measured could be fitted to a single relaxation curve. The simplest mechanism to explain the data is shown to be D⇆ lim krkfC, where D and C are believed to the “closed” and “open” forms of the acetic acid dimer. In aqueous solution this process is catalyzed by both H+ and OAc− ions. This mechanism gives a quantitative fit of the ultrasonic data and also provides complete kinetic and thermodynamic parameters. One finds that the rate constants show strong dependence on viscosity.

Graft copolymerization of vinyl monomers with modified cotton. II. Grafting of acrylonitrile and methyl methacrylate on acetylated cotton

Abstract: Ce(IV)-induced polymerization of acrylonitrile and methyl methacrylate with acetylated cotton having different acetyl contents was investigated. The extent of interaction between the cotton and monomer is dependent upon the acetyl content of the former as well as on the reaction conditions. Increasing the acetyl content caused a significant decrease in the graft yield. Increasing the acrylonitrile concentration was accompanied by a substantial increase in the graft yields. The same effect was found with the initiator up to a certain concentration, but beyond it there was a reversal. The rate of grafting increased by rising the temperature and follow the order 60° > 40° > 30°C. The Ce(IV) consumption during grafting is greater than that consumed during oxidation. The consumption of Ce(IV) by the cellulosic materials was favorably influenced by the concentrations of monomer and initiator, time, and temperature. Rates of grafting and Ce(IV) consumption during oxidation of acetylated cottons having different acetyl contents strongly support the postulated mechanism of grafting using the Ce(IV)–cellulose redox system. Ce(IV) oxidation had practically no effect on the acetyl groups (expressed as per cent combined acetic acid) of the modified cotton.

Process for producing methylene malonic esters

Abstract: A process for producing methylene malonic esters of the general formula CH2 C(-CO2R)2 , where R represents a branched or unbranched aliphatic residue of one to six C atoms, which comprises reacting a malonic ester of the general formula CH2(CO2R)2 dissolved in glacial acetic acid, where R has the meaning mentioned above, with paraformaldehyde in the presence of a catalyst at temperature stages between 0*C and the boiling point of the mixture, distilling off the solvent, and cracking the resulting product, in which process the reaction mixture contains 0.5 - 1.5 mol percent of acetic acid anhydride referred to the malonic ester.

[195c] Synthesis of O-acetylhomoserine

Abstract: Publisher Summary This chapter discusses the synthesis of ­ O -Acetylhomoserine Homoserine is acetylated with acetic anhydride in a strongly acidic medium that prevents N-acetylation Homoserine lactone is formed as a side product, which is readily separated The general method was described some years ago and applied to homoserine, but the isolation and properties of the product were not mentioned by the original authors To 2 ml of glacial acetic acid in a glass-stoppered tube was added 017 ml of perchloric acid (15 millimoles of perchloric acid and 56 millimoles of water) With slight cooling (the mixture solidifies at 14°), 081 ml (85 millimoles) of acetic anhydride was added Hydroxylamine assay showed that 21 millimoles of anhydride remained after the exothermic reaction with the water which had been added with the acetic and perchloric acids A solution of 143 mg (12 millimoles) of DL -homoserine in 1 ml of glacial acetic acid was prepared and added dropwise to the anhydride solution while agitating the latter

D-ring substituted tetracyclines

Abstract: The total synthesis of tetracycline-type antibiotics by a multistep process beginning with 3,4,10-trioxo-1,2,3,4,4a,9,9a,10-octahydroanthracenes comprising: (1) an aldol condensation with a glyoxalic acid ester to give a 2-carboxymethylidene-3,4,10-trioxo-1,2,3,4,4a,9,9a,10-octahydroanthracene ester; (2) Michael reaction of said ester with an amine to produce 3,4,10-trioxo-1,2,3,4,4a,9,9a,10-octahydroanthracene-2-( alpha -amino)acetic acid ester; (3) conversion of the triketone to the corresponding 4,10-diketone by (a) selective reduction of the Michael reaction product to the corresponding 3-hydroxy compound, followed by conversion of the 3-hydroxy compound to the corresponding 3-formyloxy compound and removal of the 3-formyloxy group by treatment with zinc dust to give a 4,10-dioxo-1,2,3,4,4a,9,9a,10-octahydroanthracene-2-( alpha -amino)acetic acid ester; or (b) conversion of the hydrochloride salt of the Michael reaction product to a lactone by reaction with p-toluenesulfonic acid and treatment of the lactone with zinc dust formic acid; (4) conversion of the 4,10-diketo-1,2,3,4,4a,9,9a,10-octahydroanthracene-2-( alpha -amino)-acetic acid to a mixed anhydride; (5) followed by acylation of a malonic acid ester with the mixed anhydride; (6) cyclization of the acyl malonate derivative to a 12a-deoxytetracycline which is then hydroxylated to a tetracycline The preparation of the 3,4,10-trioxo-1,2,3,4,4a,9,9a,10-octahydroanthracenes from benzoyl halides by (a) Friedel-Crafts reaction of a benzoyl halide with a pyrocatechol ether, eg, a di-(lower)alkyl ether, to produce a 3,4-di-(lower)alkoxybenzophenone; (b) conversion of the benzophenone by partial or complete reduction of the carbonyl group by chemical or catalytic methods to a 3,4-di-(lower)alkoxy diphenyl methanol or 3,4-di-(lower)alkoxy diphenyl methane; or to a 3,4-di-(lower)alkoxy diphenyl alkane via a Grignard reaction and reduction of the thus-produced alkanol; (c) oxidation of the 3,4-di-(lower)alkoxy diphenyl alkane, or the corresponding dihydroxy compound, to a dienedioic acid ester or dienedioic acid; (d) hydrogenation of the dienedioic acid compound to a benzyl adipic acid derivative; (e) cyclization of said compound to a 2-(2-carbalkoxyethyl)-4-tetralone by means of dehydrating or dehydrohalogenating agents; (f) cyclization of the 4-tetralone derivatives by condensation with a dialkyloxalate to give a 2-carbalkoxy 3,4,10-trioxo-octahydroanthracene; and (g) removal of the 2-substituent by decarboxylation The intermediates and final products are useful as bactericides and/or chelating agents

The photosensitized decarboxylation of carboxylic acids by benzophenone and quinones

Abstract: Benzophenone and a number of quinones have been found to photosensitize the decarboxylation of acids of the type R1XCH2·CO2H (where X = O, S, and NH). The yields of substituted hydrocarbons (R1XCH3) formed by hydrogen abstraction by the alkyl radicals (R1XĊH2) and of addition products formed by reaction of the radicals with tetrachloro-p-benzoquinone as well as reduction products of the quinones have been determined. The yields of substituted hydrocarbons were often considerably increased by the inclusion of the good hydrogen donor, thiophenol, in the reaction mixture. The amino-acid studied, was found to give a substantial yield of the related aniline as well as the expected N-methylaniline. The benzophenone-sensitized reactions were retarded by oxygen whereas those sensitized by quinones were not. Addition of acetic acid was found to retard the reaction of phenoxyacetic acid with tetrachloro-p-benzoquinone.

Electron spin resonance studies of fundamental processes in radiation- and photo-chemistry. part 6. the radiolysis of acetic acid.

Abstract: Matrix isolation studies on CH3COOH, CH3COOD and CD3COOD, using e.s.r. to identify trapped radicals, suggest a mechanism for the γ-radiolysis of acetic acid at low temperatures. It is suggested that the primary anion, CH3ĊOOH–, which is the only species observed at –196°C, dissociates into CH3CO–2 and H, the latter reacting further to give CH3CO and H2O. The molecular cation CH3ĊOOH+ is not observed, but the CH3 radicals observed in acetic acid/water matrices are thought to be decomposition products, together with CO2. The mechanism proposed for radiolysis of the solid is also compatible with product yields obtained from radiolysis of the pure liquid.

Purification of acetic acid streams by distillation

Abstract: The purification of acetic acid to remove very minor amounts of iodine in the parts per billion range is effected by means of a two-column distillation of the acid containing such iodine contamination in the presence of a chemical agent which is either an alkali metal compound, an alkaline earth metal compound, or a mixture of either of these compounds with hypophosphorous acid.

[186] A new preparation of tetrahydrofolic acid

Abstract: Publisher Summary Preparation of tetrahydrofolic acid by catalytic hydrogenation of folic acid and by enzymatic reduction of dihydrofolic acid is described in the chapter. A new method of isolation and purification of tetrahydrofolic acid from the crude reaction mixture is also described. The method is based on the observation that tetrahydrofolic acid can be eluted from a DEAE-cellulose (diethylaminoethyl-C) acetate column with diluted acetic acid in the presence of mercaptoethanol. After evaporation of the effluent, a product is obtained that is characterized as a complex between tetrahydrofolic acid and mercaptoethanol of approximate composition— C 19 H 23 N 7 O ­6 HS––CH 2 ––CH 2 ––OH . H 2 O with an estimated molecular weight of 541. This compound is slightly more stable than free tetrahydrofolic acid. The method of chromatography is applicable to the synthetic as well as to the enzymatic preparation of tetrahydrofolic acid. The product of DEAE-cellulose chromatography might be contaminated with protein. The crude incubation mixture is recommended to be passed through a Sephadex G-25 column prior to the purification on DEAE-cellulose. The enzymatic synthesis of tetrahydrofolic acid is also discussed.