Showing papers on "Acetone published in 1987"

Polymerization of phenols catalyzed by peroxidase in nonaqueous media

Abstract: Polymers produced by horseradish-peroxidase-catalyzed coupling of phenols have been explored as potential substitutes for phenol-formaldehyde resins. To overcome low substrate solubilities and product molecular weights in water, enzymatic polymerizations in aqueous-organic mixtures have been examined. Peroxidase vigorously polymerizes a number of phenols in mixtures of water with water-miscible solvents such as dioxane, acetone, di-methylformamide, and methyl formate with the solvent content up to 95%. As a result, various phenolic polymers with average molecular weights from 400 to 2.6 x 10(4) D were obtained depending on the reaction medium composition and the nature of the phenol. Peroxidase-catalyzed copolymerization of different phenols in 85% dioxane was demonstrated. Poly(p-phenylphenol) and poly(p-cresol) were enzymatically prepared on a gram scale. They had much higher melting points, and in addition, poly(p-phenylphenol) was found to have a much higher electrical conductivity than phenol-formaldehyde resins.

Methanogenic degradation of acetone by an enrichment culture.

Abstract: An anaerobic enrichment culture degraded 1 mol of acetone to 2 mol of methane and 1 mol of carbon dioxide. Two microorganisms were involved in this process, a filament-forming rod similar to Methanothrix sp. and an unknown rod with round to slightly pointed ends. Both organisms formed aggregates up to 300 micron in diameter. No fluorescing bacteria were observed indicating that hydrogen or formate-utilizing methanogens are not involved in this process. Acetate was utilized in this culture by the Methanothrix sp. Inhibition of methanogenesis by bromoethanesulfonic acid or acetylene decreased the acetone degradation rate drastically and led to the formation of 2 mol acetate per mol of acetone. Streptomycin completely inhibited acetone degradation, and neither acetate nor methane was formed. 14CO2 was incorporated exclusively into the C-1 atom of acetate indicating that acetone is degraded via carboxylation to an acetoacetate residue. It is concluded that acetone is degraded by a coculture of an eubacterium and an acetate-utilizing methanogen and that acetate is the only intermediate transferred between both. The energetical problems of the eubacterium converting acetone to acetate are discussed.

Separation of dilute aqueous butanol and acetone solutions by pervaporation through liquid membranes.

Abstract: A simultaneous extraction-stripping process is proposed for separating volatile products from fermentation broths, it is based on pervaporation through a liquid membrane supported with a hydrophobic porous membrane. The liquid membrane prepared with oleyl alcohol was selected as the most suitable for separating volatile products resulting from acetone-butanol fermentation. The separation performance and stability of the oleyl alcohol liquid membrane were investigated by using dilute aqueous butanol and acetone solutions. The oleyl alcohol liquid membrane was found to be superior by far in both selectivity and permeability of butanol to the better known silicone rubber membrane in its high selectivity for alcohols. Using the oleyl alcohol liquid membrane, the dilute aqueous butanol solutions of around 4 g/L obtained in acetone-butanol fermentation could be concentrated up to 100 times. The stability of this liquid membrane was also quite good as long as the surface tension of the feed solution was less than the critical surface tension of the support membrane. No change in the separation performance was found after the continuous usage in a long period of 100 h.

p-Nitrobenzoate esters of epoxy alcohols: convenient synthons for water-soluble epoxy alcohols

Abstract: Etude des reactions entre des nitro-4 benzoates de glycidyle et des nucleophiles (benzenethiol, methanol, NaI acetone). Formation preponderante de propanediols-1,2 substitues en 3 par le nucleophile

Two water-soluble fluorescence probes for chemiexcitation studies: sodium 9,10-dibromo- and 9, 10-diphenylanthracene-2-sulfonate. synthesis, properties and application to triplet acetone and tetramethyldioxetane

Abstract: The syntheses of sodium 9,10-dibromo- and 9,10-diphenylanthracene-2-sulfonate (DBAS and DPAS, respectively) are described and their photophysical properties determined. These two probes were used in aqueous solution studies of the kinetic parameters of tetramethyldioxetane thermolysis, which were found to be the same as in organic solvents. The yields of triplet and singlet acetone generated by the decomposition of this dioxetane in water are also comparable to the literature values in organic medium. The lifetime of triplet acetone in water was determined to be 13 ± 2 u.s by a method based on the measurement of the fluorescence decay of DBAS excited via energy transfer from triplet acetone, by the time-correlated single-photon counting technique. Sorbate ion quenches triplet acetone from tetramethyldioxetane with a rate constant smaller but close to the diffusion-controlled limit.

Pigment removal from canola oil using chlorophyllase

Abstract: Frost-damaged or prematurely harvested canola seed (rapeseed) may yield oil with a high chlorophyll content (50–60 µg/ml). Enzymatic hydrolysis of chlorophyll, added to buffer/surfactant, buffer/acetone or buffer/acetone/canola oil, to produce water-soluble chlorophyllide (green pigment) was studied using a crude chlorophyllase preparation (acetone-dried chloroplasts) from 15 to 20-day-old sugar beet seedlings. In buffer/surfactant, the optimum pH for enzyme activity was temperature dependent. At 30 C and 0.24% Triton X-100 (or 30% acetone), chlorophyllase showed maximum activity toward a crude chlorophyll preparation over the range of pH 8–10. At 60 C, the activity was more than twofold higher, with a sharp maximum at ∼pH 8. Mg2+ enhanced the activity with an optimal concentration of 50 mM. At pH 7.5, 50 C and in the presence of only 6% acetone, the enzyme showed high affinity for chlorophyll (Km=15µM or 13.5 µg/ml), suggesting that the natural chlorophyll concentrations found in green canola oils might facilitate high enzymatic efficiencies. The crude enzyme was stable in buffer/acetone at pH 7.5 and 50 C for at least two hr. With acetone concentrations as low as 6%, maximum enzyme activities in buffer and buffer/canola oil required intensive mixing (homogenization) of the various substrate, enzyme and liquid phases. In general, the rate and extent of chlorophyll hydrolysis were greater in buffer than in buffer/oil. In both reaction systems, chlorophyll hydrolysis slowed down with time due to accumulation of phytol, which proved to be a competitive inhibitor (Ki=11 µM or 3.3 µg/ml). The other hydrolysis product, chlorophyllide, did not affect enzymatic activity. Crude canola oil used in the reconstitution of green oil did not support enzymatic chlorophyll hydrolysis without prior degumming and desoaping. The optimum buffer/oil ratio of the reaction mixtures was above 2/1 (v/v).

Behavioral Toxicology of Volatile Organic Solvents. IV. Comparisons of the Rate-Decreasing Effects of Acetone, Ethyl Acetate, Methyl Ethyl Ketone, Toluene, and Carbon Disulfide on Schedule-Controlled Behavior of Mice

Abstract: The effects of acetone (ACE), ethyl acetate (EAC), methyl ethyl ketone (MEK), toluene (TOL), and carbon disulfide (CS2) were compared on schedule-controlled responding of mice. Responding (the inte...

Inclusion compounds of cholic acid with a variety of organic substances.

Abstract: Cholic acid was found to form inclusion compounds with a great variety of organic substances, such as aliphatic, alicyclic and/or aromatic alcohols, ketones, aldehydes, ethers, carboxylic acids, esters, and nitriles. The molar ratios of host to guest components were 1:1 in almost all cases.

Trace analysis of volatile polar organics by direct aqueous injection gas chromatography

Abstract: Procedures for the quantitative analysis of industrial effluents which involve concentration by solvent extraction or the purge-and-trap method are time-consuming, labor-intensive, and prone to error. Direct aqueous injection gas chromatography using an electron-capture detector for the analysis of volatile halocarbons at the ppb level is in routine use in many laboratories. We now discuss the development of a similar protocol for the analysis of volatile polar organics such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and tretrahydrofuran using a flame-ionization detector.

Propan-2-ol adsorption and decomposition on zinc oxide promoted by alkali metal

Abstract: Temperature-programmed desorption has been used to investigate the adsorption and decomposition of propan-2-ol on potassium-promoted polycrystalline ZnO catalysts. The observed desorption and decomposition products were as follows: reversible adsorption yielding the parent alcohol, dehydrogenation to acetone and hydrogen, dehydration to propene and water, and an oxidative decomposition to carbon dioxide, hydrogen and methane. Three propene states were observed, but the water produced was mainly readsorbed and desorbed at high temperature. Only propene was formed in a significant amount on the Zn(0001) polar surface, while both acetone and propene were produced on the non-polar (10text-decoration:overline10) faces. Limited reaction took place on the O(000text-decoration:overline1) surface to yield a small quantity of propene. Alkali-metal promotion was found to change the reaction selectivity such that dehydration was completely suppressed on both polar surfaces and to a significant extent on the non-polar face. Dehydrogenation of propan-2-ol to acetone was enhanced by potassium promotion, as was the quantity of reversibly adsorbed propan-2-ol.

Efficient synthesis of acetone from ethanol over ZnO–CaO catalyst

Abstract: ZnO–CaO (molar ratio 9 : 1) exhibited a high catalytic activity (100% conversion) and selectivity (91%) for formation of acetone from ethanol at 673 K.

Protective coatings for gas tank containers

Abstract: A corrosion resistant coating for application to a metal substrate including powdered metal selected from the group consisting essentially of zinc, cadmium, stainless steel, aluminum and alloys and blends thereof; a linear epoxy or phenoxy resin having a molecular weight of less than 15,000 and essentially no highly reactive terminal epoxy group; a cross-linking urethane resin; an active organic solvent selected from the group consisting essentially of acetone, methyl ethyl ketone, methyl isobutyl ketone, dimethylformamide, and blends thereof; and an inactive organic solvent selected from the group consisting essentially of aromatic hydrocarbons, alcohols, and blends thereof.

Immobilized 3-aminopyridine on silica: Adsorption of some metal (II) chlorides in non-aqueous solutions

Abstract: A new silica gel, modified by 3-(N-propyl) aminopyridine, having 2.5 × 10−4 mol g−1 of the immobilized organic molecule, can adsorb metal (II) chlorides from ethanol and acetone at 298 K. The chemisorption isotherms could be fitted by a modified Langmuir equation and are similar for all metals. The capacity to adsorb ions from solution showed the sequence Cu > Co > Zn and Cu > Zn > Co > Ni in acetone and ethanol, respectively. With exception of CuCl2 which gave ΔH = 2.38 ± 0.05 kJ mol−1, all other interactions between metal ions and immobilized material are zero in acetone. Based on an approximate calculation, it was estimated that the anchored groups protrude 1.1 nm from the surface, and the mean distance between them is 1.86 nm.

Method for maximizing yield and purity of bisphenol A

Abstract: Product losses and color formation are sometimes encountered in the synthesis of bisphenol A from phenol and acetone in the presence of a cation exchange resin, particularly in the crude product stream from which bisphenol A has been separated via its phenol adduct. Such losses are suppressed and the crude product stream stabilized and decolorized by contact with an anion exchange resin.

The synthesis of some thiophenophanes and attempted cyclisations to polycyclic thiophenium salts

Abstract: 5,10-Diphenylcyclotrideca-2,4,10,12-tetraene-6,8-diyn-1-one (28), 5,6,7,8-tetrahydrodibenzo[a,g]cyclotridecen-15-one (21), and 13,14,16,17-tetrahydro-5,6,7,8-tetradehydrodibenzo[a,g]cyclotridecen-15-one (40) were synthesized. All attempts to add hydrogen sulphide across the triple bonds of these compounds to give thiophenes failed. 13,14,16,17-Tetrahydro-5,8-epithiodibenzo[a,g]cyclotridecen-15-one (43), from which hydrogen sulphide was removed by DDQ or chloroanil to give the ketone (40), was synthesized via the copper(II) acetate oxidation of 1,5-bis(2-ethynylphenyl)pentan-3-one (36). This ketone was obtained from 2-iodobenzaldehyde which on successive treatment with acetone, and ethynyltrimethylsilane yielded 1,5-bis(2-trimethylsilylethynylphenyl)penta-1,4-dien-3-one (18). Tributyltin hydride reduced the vinyl double bonds only in this ketone, and subsequent hydrolysis gave the ketone (36). Reduction of the, cyclic ketone (40) with sodium borohydride gave the alcohol (41), sodium sulphide converted the diyne grouping into a thiophene ring giving the thiophene alcohol (42), and chromic acid now yielded the ketone (43). Attempts to convert this alcohol (42) and ketone (43) into pentacyclic sulphonium salts or related compounds resulted in elimination of oxygen and the formation of olefins.

Process for recovery of acetone

Abstract: This invention is a process for purifying crude acetone obtained by cleavage of cumene hydroperoxide, said crude acetone containing aldehyde impurities and appreciable amounts of unreacted cumene, by fractionally distilling the acetone in a multiple plate distillation column, said process comprising: continuously feeding crude acetone; continuously feeding a dilute aqueous solution of an alkaline material at a point above the crude acetone feed point; and controlling the temperature profile of the column by adjusting the amount of liquid acetone removed in step (c) to maintain a preselected temperature on a plate in the region between the crude acetone feed point and the alkaline material feed point.

Method for purification of carotene-containing concentrate

Abstract: A method for purification of a carotene-containing concentrate by chromatography in which a liquid con­taining a carotene-containing concentrate is fed to a filler to adsorb the concentrate on the filler and the carotene component is subsequently eluted and collected by feeding an eluant to the filler. The silica gel or activated alumina pre-treated with a polar solvent selected from acetone, C₁-C₅ alcohols, C₁-C₃ alkyl esters of acetic acid, acetonitrile, dioxane, diethyl ether or mixtures thereof and a non-polar solvent selected from C₅-C₂₀ hydrocarbons, carbon tetrachloride, carbon disulfide or mixtures thereof is used as the filler, and a solvent mixture of the above-mentioned polar solvent and the above-mentioned nonpolar solvent containing 0.005% to 5.0% by weight of the polar solvent is used as the eluant.