Showing papers on "Ether published in 1988"

Characterization of an extracellular lignin peroxidase of the lignocellulolytic actinomycete Streptomyces viridosporus

Abstract: Previously we reported production of an extracellular lignin-inducible peroxidase by Streptomyces viridosporus (M. Ramachandra, D.L. Crawford, and A.L. Pometto III, Appl. Environ. Microbiol. 53:2754-2760, 1987). This peroxidase was shown to oxidize 3,4-dihydroxyphenylalanine, 2,4-dichlorophenol, homoprotocatechuic acid, caffeic acid, and N,N,N',N'-tetramethylphenylenediamine and was found in higher than normal levels in strains enhanced for lignocellulose degradation. In the present study, we used a pure extracellular enzyme preparation with high peroxidase isoform P3 activity to oxidize lignin substructure model compounds of both the 1,2-diaryl propane and arylglycerol-beta-aryl ether types and containing C alpha-carbonyl and C alpha-hydroxyl groups. The reactions were monitored by gas chromatography-mass spectrometry and high-pressure liquid chromatography techniques. In the presence, but not the absence, of hydrogen peroxide, the enzyme preparation catalyzed C alpha-C beta bond cleavage in the side chains of the diaryl ethers 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)propane-1,3-diol (I) and 1-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)propan-1-one (II) and the diaryl ethane 1-(4-methoxyphenyl)-2-(phenyl)ethan-1-one (III). Rapid hydrogen peroxide consumption was observed when the enzyme preparation was added to either milled corn lignin or lignocellulose. Additional characterizations showed that this enzyme is a heme protein (Soret band, 408 nm) and a major component of the ligninolytic system of S. viridosporus T7A. This is the first report of a lignin peroxidase in a bacterium. We have designated this new lignin peroxidase as ALiP-P3.

The discovery of crown ethers.

Abstract: The discovery of the crown ethers stemmed from efforts to control the catalytic activity of vanadium and copper by complexation with multidentate ligands. The first crown ether, 2,3,11,12-dibenzo-1,4,7,10,13,16-hexaoxacyclo-octadeca-2,11-diene, was obtained in 0.4% yield during an attempt to prepare a phenolic ligand from catechol and bis(2-chloroethyl)ether. This compound, which complexed with the sodium cation, was the first compound known to display such activity and became known as dibenzo-18-crown-6, an 18-atom heterocycle containing 6 oxygen atoms. Some 60 related compounds were made involving heterocyclic rings containing 12 to 60 atoms including 4 and 10 oxygen atoms. There are optimum polyether ring sizes for the different alkali metal cations: 15 to 18 for sodium, 18 for potassium, and 18 to 21 for cesium. Complexes having polyether to cation ratios of 1:1, 3:2, and 2:1 were prepared. Solubilization of inorganic salts in aprotic solvents, especially by saturated crown ethers, was demonstrated.

Miscible blends of poly(aryl ether ketone)s and polyetherimides

Abstract: A new class of high performance engineering resins, poly(aryl ether ketone)s, has emerged with a property balance not offered by existing polymeric materials Blends of poly(aryl ether ketone)s with other polymers have not been described in the open literature, although several patents have revealed interesting and important properties of certain blend combinations Ultem polyetherimide has been found to be miscible over the entire composition range and as a consequence is a very effective heat distortion temperature builder, particularly if the poly(aryl ether ketone) is allowed to crystallize Crystallization kinetics and mechanical properties were studied as a function of blend composition and poly(aryl ether ketone) melting point The blends exhibited a maximum in toughness at intermediate compositions along with an accompanying maximum in poly(aryl ether ketone) crystallinity The chemical resistance of the polyetherimide is significantly improved with the addition of a poly(aryl ether ketone) In organic chemicals, the improvement was expected when tensile stress was plotted vs log time to rupture However, in aqueous bases, the resistance of the blends was much greater than anticipated This property profile suggests that these blends will be useful as thermoplastic composite matrix resins

Studies on fluoroalkylation and fluoroalkoxylation. Part 28. Palladium(0)-induced addition of fluoroalkyl iodides to alkenes: an electron transfer process

Abstract: In the presence of catalytic amounts of tetrakis(triphenylphosphine)palladium, fluoroalkyl iodides react readily with alkenes under mild conditions to give the corresponding adducts in high yields. Dichlorobis(triphenylphosphine)palladium or fluoroalkylbis(triphenylphosphine)palladium iodide fails to induce the reaction under the same conditions. Di-iodobis(triphenylphosphine)palladium, but not the fluoroalkylated complex of palladium, Pdl(PPh3)2RF, is formed in the reaction confirmed by X-ray photoelectron spectroscopy. The reaction can be partially suppressed by radical inhibitors, such as 2-nitro-2-nitrosopropane or di-t-butyl nitroxide, but no effects are observed by the presence of oxygen in air or p-dinitrobenzene [molar ratio p-DNB:Pd0= 1:1] unless an excess of p-DNB(10:1) was added. In the presence of diallyl ether, fluoroalkylated tetrahydrofuran derivatives are formed. All these results indicate that a radical-chain process initiated by single electron transfer from palladium(0) to iodide might be involved. Also, the formation of fluoroalkylbis(triphenylphosphine)palladium iodide is proved to proceed through a radical intermediate by e.s.r. trapping techniques.

Solvent-resistant, compatible blends of polyphenylene ethers and linear polyesters

Abstract: Impact- and solvent-resistant resin blends are prepared from a polyphenylene ether, or blend thereof with a polystyrene, a linear polyester such as a poly(alkylene dicarboxylate), at least one elastomeric polyphenylene ether-compatible impact modifier and at least one polymer containing a substantial proportion of aromatic polycarbonate units as a compatibilizing agent. There may also be present a minor amount of at least one epoxide and/or masked isocyanate such as triglycidyl isocyanurate or a glycidyl methacrylate polymer. The polyphenylene ether is preferably inactivated by reaction with at least one non-volatile carboxylic acid or anhydride and/or by extrusion with vacuum venting.

Pervaporation process for separating alcohols from ethers

Abstract: The present invention is an improved process for separating alcohols from ethers and/or hydrocarbon raffinate in an etherification process. The excess alcohol reactant, which forms azeotrope mixtures with the product ethers and C 4 -C 7 raffinate, is removed by passing the liquid azeotrope mixture over a pervaporation membrane which effectively breaks the azeotrope and permeates the alcohol with high flux and high selectivity. In a typical etherification process, one or more pervaporation membrane units can be located ahead of the ether/raffinate distillation step, in conjunction with the distillation step with a liquid side draw, after the distillation step, or a combination of any of the above. The present invention also provides an improved process for separating alcohols from ethers and/or hydrocarbon raffinate in an ether decomposition process for the production of high purity iso-alkene products. In this embodiment, one or more pervaporation membranes are used to recover alcohols from the decomposition product stream.

Quick drying ink for ink jet recording

Abstract: PURPOSE:To obtain the titled ink usable without causing clogging of an ejection nozzle and having excellent quick-dryability and roundness of printed dot, by compounding a water-soluble dye, a mixture of a specific polyhydric alcohol and specific derivative thereof, a specific surfactant and water at specific ratios. CONSTITUTION:The objective ink is composed of (A) 0.1-9wt% water-soluble dye, (B) 7-45wt% mixture of (a) a polyhydric alcohol derivative selected from the group of (mono, di, tri)ethylene glycol alkyl ethers and (mono, di, tri)ethylene glycol alcohol ether acetates (e.g. diethylene glycol monobutyl ether) and (b) a polyhydric alcohol selected from the group of (mono, di, tri, tetra, poly)ethylene glycol, propylene glycol and glycerol (e.g. glycerol), (C) a surfactant exhibiting a surface tension of 20-50dyne.cm when dissolved in water at micelle concentration and (D) water.

Paint removing compositions

Abstract: Water soluble paint remover compositions for the removal of uncured paint are disclosed which avoid the use of toxic organic solvent, in particular, methylene chloride. The inventive compositions comprise an organic carboxylic acid, N-methyl-2-pyrrolidone, and an alkylen glycol ether. Methods for use of the compositions are also disclosed.

Purification and characterization of a bacterial dehalogenase with activity toward halogenated alkanes, alcohols and ethers

Abstract: An enzyme that is capable of hydrolytic conversion of halogenated aliphatic hydrocarbons to their corresponding alcohols was purified from a 1,6-dichlorohexane-degrading bacterium. The dehalogenase was found to be a monomeric protein of relative molecular mass 28,000. The affinity for its substrates was relatively low with Km values for short-chain haloalkanes in the range 0.1-0.9 mM. The aliphatic dehalogenase showed a much broader substrate range than has been reported for halidohydrolases so far. Novel classes of substrates include dihalomethanes, C5-C9 1-halo-n-alkanes, secondary alkylhalides, halogenated alcohols and chlorinated ethers. Several of these compounds are important environmental pollutants, e.g. methylbromide, dibromomethane, 1,2-dibromoethane, 1,3-dichloropropene, and bis(2-chloroethyl)ether. The degradation of chiral 2-bromoalkanes appeared to proceed without stereochemical preference. Optically active 2-bromobutane was converted with inversion of configuration at the chiral carbon atom, suggesting that the dehalogenase reaction proceeds by a nucleophilic substitution involving a carboxyl group or base catalysis.

Efficient synthesis of sterically hindered chiral binaphthol derivatives.

Abstract: A highly effective method for preparation of a variety of sterically hindered chiral binaphthol derivatives has been described which involves the intramolecular 1,3-rearrangement of bis(trialkylsilyl ether) of chiral 3,3′-dibromo-1,1′-bi-2-naphthol with t-BuLi.

Arylamine-containing polyhydroxy ether resins

Abstract: Polymeric tertiary arylamine compounds of the phenoxy resin type which find utility especially in electrophotographic imaging.

Hard surface cleaning and polishing compositions

Abstract: A composition is described which cleans, imparts water repellency and polishes hard surfaces. This composition comprises a solvent mixture of a glycol ether, a lower aliphatic alcohol, a hydrocarbon solvent and water, together with an organic polysiloxane, a silane, and a polycarboxylic chelating acid. A preferred composition contains propylene glycol monomethyl ether, isopropanol, high flash naphtha or mineral spirits, a polydimethysiloxane, citric acid, and orange oil terpene.

Synthesis and properties of bismaleimide resins containing ether bonds

Abstract: New bismaleimides containing ether bonds were prepared. The thermal properties of the bismaleimides were investigated by differential scanning calorimetry (DSC). The effects of structure of the bismaleimides and curing conditions on the thermal and mechanical properties of the cured resins such as initial decomposition temperature (Td), glass transition temperature (Tg), and flexural strength were studied. The introduction of ether bonds to bismaleimide resins decreased the brittleness of the resins without reductions in their heat-resistant properties.

Spontaneous and reversible interaction of vanadium(V) oxyanions with amine derivatives

Abstract: The interaction between vanadate and tri- or tetradentate ethanolamine derivatives has been studied by using /sup 51/V NMR spectroscopy. The reactions occur spontaneously in aqueous solutions, at ambient temperatures and in the physiological pH range. In addition to one amine group and one hydroxyl group, the ethanolamine derivative should contain a third and/or fourth functionality that is an alcohol, a carboxylic acid, a phosphonium acid, or an amine. The reactions are highly dependent on pH, concentrations of monomeric vanadate, amine. The stability constants for the complexes are minimum orders of magnitude greater than those found for vanadate derivatives of corresponding ether derivatives, and the high stability is associated with the central nitrogen. Only one vanadium complex is formed in substantial amounts in the reaction of ethanolamine derivatives with vanadate, and that complex is mononuclear in vanadium. Several of the ethanolamine derivatives that form complexes are commonly used buffers in biological and biomedical studies in vitro. 22 refs., 10 figs., 7 tabs.

Cleaning preparations for hard surfaces

Abstract: Aqueous cleaning preparations for hard surfaces containing surfactants and from 1 to 20% by weight propylene glycol tert.-butyl ether as an essential component.

Process for manufacturing a tertiary alkyl ether by reactive distillation

Abstract: Process for manufacturing methyl tert-butyl ether (MTBE) by reacting methanol with isobutene-containing hydrocarbons in a reaction zone comprising alternate beds of sulfonated resin catalyst and catalyst-free distillation zones, said zones also comprising liquid redistribution plates.