Showing papers on "Ether published in 1989"

Groundwater chemicals desk reference

Abstract: Abbreviations and symbols acenaphtlene acenaphthylene acetone acrolein acrylonitrile aldrin anthracene benzene benzidine benzo(a)anthracene benzo(b)fluoranthene benzo(k)fluoranthene benzoic acid benzo(ghi)perylene benzo(a)pyrene benzyl alcohol benzyl butyl phthalate BHC Bis(2-chloroethoxy)methane Bis(2-chloroethyl)ether bis(2-chloroisopropyl)ether Bis(2-ethylhexyl)phthalate bromodichloromethane bromoform 4-bromophenyl phenyl ether 2-butanone carbon disulfide carbon tetrachloride chlordane cis-chlordane trans-chlordane 4-chloroaniline chlorobenzene p-chloro-m-creson chloroethane 2-chloroethyl vinyl ether chloroform 2-chloronaphthalene 2-chlorophenol 4-chlorophenyl-phenyl ether chrysene p,p '-DDD p,p'-DDT dibenz(ah)anthracene dibenzofuran dibromochloromethane di-n-butyl phthalate 1,2-dichlorobenzene 1,3-dichlorobenzene 1,4-dichlorobenzene 3,3'dichlorobenzidine dichlorodifluromethane 1,1-dichloroethane 1,2-dichloroethane 1,1-dichloroethylene trans - 1,2-dichloroethylene 2,4-dichlorophenol 1,30dichloropropane cis-1,3-dichloropropylene trans-1,3- dichloroproylene dieldrin diethyl phthlate 2,4-dimethylphenol dimethyl phthalate 4,6-dinitro-o-cresol 2,4- dichlorophenol 2,4-dinitrotoluene 2,6-dinitrotoluene di-n-octyl phthalate 1,2-diphenylhydrazine a-Endosulfan b-Endosulfan endosulfan sulfate endrin endrin aldehyde ethylbenzene fluoranthene fluorene heptachlor heptachlor epoxide hexachlorobenzene hexachlorobutadiene hexachlorocyclopentadiene hexachloroethane 2-hexanone indeno (1,2,3-cd)pyrene isophrone lindane methoxychlor p methyl bromide methyl chloride methylene chloride 2-thehylnaphthalene 4-methyl-2-pentanone 2-methylphenol 4-mthylphenol naphthalene 2-nitroaniline 3-nitrophenol N-nitrosodimethylamine N-nitrosodiphenylamine N-nitrosodi-n-propylamine PCB-1016 PCB-1221 PCB-1232 PCB-1242 PCB-1248 PCB-1254 PCB-1260 pentachlorophenol phenanthrene phenol pyrene styrene TCDD 1,1,2,2-tetrachloroethane tetrachloroethylene 1,1,2-trichloroethane trichloroethylene trichlorofluoromethane 2,4,5-trichlorophenol 2,4,6-trichlorophenol vinyl acetate vinyl chloride o-xylene m-xylene p-xylene conversion factors U.S. EPA approved test methods CAS.

Crown ethers and analogs

Abstract: Synthesis of crown ethers and analogs organic transformations mediated by macrocyclic multidentate ligands recent advances in the synthesis and uses of macrocyclic multidentate ligands crown ethers: complexes and selectivity geometry of the ether, sulphide and hydroxyl groups and structural chemistry of macrocyclic and noncyclic polyether compounds. Appendices: geometry of ether, sulphide and hydroxyl groups and structural chemistry of macrocyclic and noncyclic polyether compounds complexation of aryldiazonium ions by polyethers completion of aryldiazonium ions by polyethers.

Palladium-catalyzed synthesis of 2-substituted indoles

Abstract: The palladium(0)-catalyzed cross-coupling reaction of alkynylstannanes with 2-bromoanilines or 2-trifloxyanilines results in the formation of 2-alkynylanilines. The coupling reaction tolerates substituents on the anilines, including ester, ether, chloro, and trifloxy groups. A palladium(II)-catalyzed intramolecular cyclization provides 2-substituted indoles. The cyclization proceeds without the need to reoxidize the metal and is most efficient with aliphatic substituents on the alkynyl terminus.

Rate constants for hydrogen abstraction reactions of the sulfate radical, SO4−. Alkanes and ethers

Abstract: Rate constants have been determined for the reactions of SO4− with a series of alkanes and ethers. The SO4− radical was produced by the laser-flash photolysis of persulfate, S2O82−. For methane, only an upper limit of 1 × 106 M−1 s−1 could be determined. For ethane, propane, and 2-methylpropane, rate constants of 0.44, 4.0, and 10.5 × 107 M−1 s−1 were found. For ethyl and n-propyl ether, rate constants of 1.3 × 108 and 2.2 × 108 M−1 s−1 were found and for 1,4-dioxane and tetrahydrofuran, rate constants of 7.2 × 107 and 2.8 × 108 were obtained. The reaction of SO4− with allyl alcohol was also studied and found to have a rate constant of 1.4 × 109 M−1 s−1.

Sodium-selective polymeric membrane electrodes based on calix[4]arene ionophores

Abstract: Sodium-selective electrodes were prepared with polymeric membranes containing ester and ketone derivatives of p-tert-butyl calix[4]arene. The electrodes were prepared with 2-nitrophenyl octyl ether as the solvent mediator and potassium tetrakis(p-chlorophenyl)borate as the ion exchanger in a poly(vinyl chloride) matrix. Several of the ligands examined produced electrodes with near-Nernstian slopes, detection limits of ca. 10–5M for sodium and excellent selectivity against a range of common cations.

p-coumaric acid - a monomer in the sporopollenin skeleton.

Abstract: Sporopollenin obtained from wings of Pinus mugo (Turra) pollen was analysed by pyrolysis mass spectrometry. In the spectrum, mass peaks which are characteristic for p-coumaric acid were dominant. p-Coumaric acid was the main degradation compound when the wing material was treated by a gentle method using AII3, and also when the remaining residue of the treated sporopollenin material was saponified. It is therefore assumed that p-coumaric acid is a genuine structural unit in the sporopollenin skeleton. In addition, the effects of AII3 treatment indicate that the p-coumaric acid might be bound by ether linkages.

Relations between structure and nicotine-like activity: X-ray crystal structure analysis of (−)−cytisine and (−)−lobeline hydrochloride and a comparison with (−)−nicotine and other nicotine-like compounds

Abstract: 1. Although (-)-cytisine is a rigid structure, it occurs in the crystal in two distinct but very similar conformations in which the pyridone ring is tilted relative to the charged nitrogen atom at much the same angle as the pyridine ring is in (-)-nicotine hydrogen iodide. The carbonyl group in the pyridone ring of (-)-cytisine, however, is on the side of the ring opposite to pyridine nitrogen in (-)-nicotine. 2. The pKa of (-)-lobeline HCl at 25 degrees C is 8.6 (approx), indicating that (-)-lobeline is at least 90% in the protonated form at physiological pH (7.6). It is probably the phenyl 2-keto-ethyl part of (-)-lobeline, rather than the phenyl 2-hydroxy-ethyl part, which interacts with the receptor. 3. The combination within one molecule of a charged ('onium') nitrogen atom lying out of the plane of, and some distance (4.5-6.5 A) from, an aromatic ring is common to many compounds with nicotine-like activity (e.g. nicotine, cytisine, choline phenyl ether bromide, dimethyl-phenyl-piperazinium (DMPP) iodide, coryneine iodide and m-hydroxyphenylpropyl trimethyl ammonium iodide). In some molecules the aromatic ring can be replaced by an unsaturated group, such as carbonyl (e.g. acetylcholine) or double-bonds (e.g. anatoxin). 4. Activity at nicotinic receptors appears to involve interactions between the positively charged nitrogen atom and a negatively charged group, probably close to cysteine residues 192 and 193 in the receptor. It is suggested that rather than specific groups in the molecule also being involved, activity at nicotinic receptors depends on interactions between a flat part of the drug containing double-bonds, or systems of double bonds, and a planar area in the receptor, possibly tyrosine or phenylalanine residues.

Effects of Iron Oxidation State on the Specific Surface Area of Nontronite

Abstract: The effect of Fe oxidation state on the specific surface area, Sin, ofnontronite was studied using the < 2-tzm, Na§ fraction of the SWa-1 and Garfield nontronite reference clays. The reduction of structural Fe 3+ in the octahedral sheet of the nontronite decreased Sm as measured by the adsorption of 2-ethoxyethanol (ethylene glycol-monoethyl ether, EGME). The swellability in water of the nontronite also decreased during reduction. The amount of nonexchangeable Na +, on the other hand, increased with increasing Fe 2+ content and was highly correlated with EGME adsorption (r = -.985). The relationship between Sm and Fe 2+ was attributed to the collapse of partially or fully expanded layers to unexpanded layers.

Radiation-curable protective coating composition

Abstract: Normally solid, organic solvent-soluble, thermoplastic, polyethylenically-unsaturated, cellulosic polyurethane polymers are provided. These cellulosic polyurethane polymers comprise one or more cellulose ether or ester segments, one or more alkylene moieties having at least two carbon atoms and which can be substituted or interrupted by ether oxygen atoms, ester groups, or phenylene groups, two or more residues of diisocyanates, the segments, moieties, and residues being linked together by linking groups with the proviso that said alkylene moieties contain sufficient ethylenic unsaturation that said polymer can be crosslinked to a solvent-insoluble state. The cellulosic polyurethane polymers can be obtained by the polymerization of a reaction mixture comprising (a) aliphatic or cycloaliphatic diol comprising sufficient ethylenically-unsaturated diol to permit crosslinking of the polymerization product to a solvent-insoluble state; (b) organic solvent-soluble cellulose ether or ester having residual unreacted cellulosic hydroxyl groups; and (c) organic diisocyanate. The reaction product may optionally also contain primary or secondary aliphatic or aromatic diamines or dithiols. Also provided are coating compositions and shaped articles and methods for preparing same.

Dioxygenolytic cleavage of aryl ether bonds: 1, 10‐dihydro‐1, 10‐dihydroxyfluoren‐9‐one, a novel arene dihydrodiol as evidence for angular dioxygenation of dibenzofuran

Abstract: Two dibenzofuran degrading bacteria, Brevibacterium strain DPO 1361 and strain DPO 220, were found to utilize fluorene as sole source of carbon and energy. Cells which were grown on dibenzofuran, transformed fluorene into a number of products. For five of the seven metabolites isolated, the structure could be established unequivocally. Accumulation of one metabolite, 1,10-dihydroxy-1, 10-dihydrofluoren-9-one, indicated the presence of a novel type of dioxygenase, attacking polynuclear aromatic systems in the unusual angular position. Dibenzofuran degradation is proposed to likewise proceed via initial angular dioxygenation. Only aryl oxygen ether bond, which normally is extremely stable, is thus transformed to a hemiacetal. After spontaneous cleavage and subsequent rearomatization by dehydration, 2,2′,3-trihydroxybiphenyl [3-(2-hydroxyphenyl)-catechol] thus results as the immediate product of the first enzymatic reaction in the degradation sequence.

Modification of the structure and electrochemical properties of poly(thiophene) by ether groups

Abstract: Poly[3-(3,6-dioxaheptyl)thiophene] has been synthesised by electropolymerisation; this highly conducting electroactive polymer exhibits specific interactions with lithium cations.

Liquid herbicidal agents

Abstract: New liq. herbicides contain racemic or L-phosphinothricin (I) or its lower alkyl esters or salts with acids or bases in combination with a surface active agent in the form of (a) (12-18C alkyl-dimethyl-, 10-18C fatty acid amidopropyl-dimethyl-or 10-18C fatty acid amidoethyl-dimethyl-amine oxides, (b) the betaine of coco-alkyl-dimethylaminoacetic acid or coco-alkylaminopropionic acid, (c) 12-18C alkanesulphonates and their mixts. with 10-18C fatty alcohol polyglycol ether sulphosuccinic acid half-esters or 10-18C fatty alcohol polyglycol ether sulphates, (d) 12-18C alkyl sulphosuccinic acid half-esters or 10-18C fatty alcohol polyglycol ether sulphosuccinic acid half-esters and esters and their mixts. with 10-18C fatty alcohol polyglycol ether sulphates, or (e) 12-20C alpha-olefin sulphonates and their mixts. with 10-18C fatty alcohol polyglycol ether sulphates, 10-18C fatty alcohol polyglycol ether sulphosuccinic acid half-esters or 12-18 C alkyl sulphosuccinic acid half-esters (sulphonates being alkali, ammonium, alkaline earth or substd. alkyl; or alkanolamine salts of the corresponding sulphonic or sulphuric acids).

Polyphenylene sulfide resin composition

Abstract: A resin composition comprising polyphenylene sulfide, polyphenylene ether and polyamide is modified with the addition of 0.01 to 10 parts by weight of a compound having a functional group, whereby impact resistance of a molded article produced from the resin composition is improved.

The Effects of Radiation on High-Technology Polymers

Abstract: Recent studies of radiation effects on polymer materials used in structures and components are discussed in reviews and reports. Topics examined include the radiation chemistry of polymers, spectroscopic methods in polymer studies, the photophysics of hydroxyphenylbenzotriazole polymer photostabilizers, and the radiolysis of polycarboxylic acids and model compounds. Consideration is given to polymers for electronics applications, X-ray-sensitive alternating copolymers, the radiation durability of polymeric-matrix composites, and radiation-resistant amorphous all-aromatic poly(arylene ether sulfones).

Polylactones. 16. Cationic Polymerization of Trimethylene Carbonate and Other Cyclic Carbonates

Abstract: 1,3-Dioxanone-2 (trimethylene carbonate) was polymerized by use of methyl triflate or triethyloxonium fluoborate under various reaction conditions. Chloroform, 1,2-dichloroethane, and nitrobenzene were used as solvents; the temperature was varied between 25 and 50°C; and the monomer/initiator ratio between 50 and 400. However, inherent viscosities above 0.29 dL/g ( M n > 6000) were never obtained, owing to side reactions such as backbiting and formation of ether groups. IR and 1H-NMR spectroscopy revealed that the polymerization mechanism agrees with that of the cationic polymerization of lactones in that propagation involves cleavage of the alkyl-oxygen bond. The active cationic chain end and the dead methylcarbonate end groups were identified by means of 1H-NMR spectra. A reaction mechanism for the formation of ether groups is discussed. Furthermore, 1H-NMR spectroscopy indicated that ethylene carbonate and biphenyl-2,2′-carbonate do not react with methyl triflate at 20, 60, or even 100°C.

Binding-site Analysis of the Ether Linkages between Lignin and Hemicelluloses in Lignin-Carbohydrate Complexes by DDQ-Oxidation

Abstract: Lignin-carbohydrate complexes (LCC; nor-C-1-M, com-C-1-A) isolated from normal and compression woods of Pinus densiflora were hydrolyzed with two types of cellulase preparations, and the hydrolyzates formed were fractionated by adsorption chromatography on polyvinyl gel into water-soluble materials and LCC fragments. To elucidate the binding sites between the lignin and carbohydrate, the cellulase-degraded LCC fragments were subjected to acetylation, and then oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), which was confirmed to oxidatively cleave the benzyl ether linkages between the lignin and carbohydrate. The DDQ-oxidized fraction was then methylated by the method of Prehm, hydrolyzed, reduced and acetylated. A GC-MS analysis of the methylated sugar revealed that alditol acetates from 6-O-methyl mannose, 6-O-methyl galactose, 6-O-methyl glucose and a small amount of their 2-O- or 3-O-methyl isomers existed in both methylated fractions. 2-O-Methyl xylose and 3-O-methyl xylose were also ...

Acetylenes disubstituted with a phenyl group and a 2-substituted chromanyl or thiochromanyl group having retinoid-like activity

Abstract: Retinoid-like activity is exhibited by compounds of the formula ##STR1## where X is S, O; R 1 , R 2 and R 3 are hydrogen or lower alkyl; R 4 and R 5 are hydrogen or lower alkyl with the proviso that R 4 and R 5 cannot both be hydrogen, R 6 is hydrogen, lower alkyl, lower alkenyl, lower cycloalkyl or halogen; n is 0-5, and B is H, --COOH or a pharmaceutically acceptable salt, ester or amide thereof, --CH 2 OH or an ether or ester derivative, or --CHO or an acetal derivative, or --COR 1 or a ketal derivative where R 1 is --(CH 2 ) m CH 3 where m is 0-4, or a pharmaceutically acceptable salt thereof.

Chroman esters of phenols and benzoic acids having retinoid-like activity

Abstract: Retinoid like activity is exhibited by compounds of the formula ##STR1## wherein the R1 -R7 groups are independently H or straight chain or branched chain lower alkyl or cycloalkyl of 1 to 6 carbons; X symbolizes an ester or thioester linkage, Y is cycloalkyl or branched chain alkyl of 1 to 6 carbons or is (CH2) where n is an integer between 0 to 6 or is an alkenyl group of 2 to 6 carbons, or an alkynyl group of 2 to 6 carbons; and Z is H, OH, OR', OCOR', --COOH or a pharmaceutically acceptable salt, ester or amide thereof, --CH2 OH or an ether or ester derivative, or --CHO or an acetal derivative, or --COR' or a ketal derivative where R' is an alkyl, cycloalkyl or alkenyl group containing 1 to 6 carbons, or a phenylalkyl, phenyl or substituted phenyl group.

Concerning the Synthesis of [1.1.1]Propellane

Abstract: The reaction of 1,1-dibromo-2,2-bis(chloromethyl)cyclopropane (2) with methyllithium in ether led to a solution of [1.1.1]-propellane (1) in a yield of 70%. 1 could also be prepared free of solvent by reaction of 2 with lithium powder in triglyme/n-decane at 73°C.

Heavy duty hard surface liquid detergent

Abstract: A single phase, highly aklaline, liquid detergent composition particularly effective in removing airborne kitchen grease from hard surfaces is provided which comprises, by weight: a. from about 1 to 5% of a surfactant selected from the group consisting of nonionic surfactants (including alcohol ethoxylates and amine oxides, wherein the alcohol ethoxylate is selected from the group consisting of linear primary alcohol ethoxylates, random secondary alcohol ethoxylates) and amphoteric surfactants (comprising water-soluble betaines) and mixtures thereof; b. about 2% of a builder selected from the group consisting of tetrapotassium pyrophosphate (TKPP), sodium tripolyphosphate (STPP), sodium metasilicate, sodium carbonate, sodium bicarbonate, and c. about 2% of an alkanolamine selected from the group consisting of monoethanolamine, diethanolamine, and triethanolamine; d. from about 2 to 8% of at least one water miscible, preferably polar organic solvent selected from the group consisting of water soluble glycol ethers (including diethylene glycol monobutyl ether, ethylene glycol monobutyl ether, ethylene glycol methyl ether, and propylene glycol methyl ether) and alkyl acetates; and e. water.

Layer-by-layer surface freezing of freely suspended liquid-crystal films.

Abstract: Computer-enhanced polarized video microscopy has been used to study the discrete layer-by-layer surface ordering transitions of freely suspended films of 4-(«-nonyloxy)benzylidene-4-(«-butyl)aniline (90 .4) . Stable tilted hexatic smectic-7 surface layers form on both free surfaces of the 2D-liquid smectic-^ interior in a monolayer, bilayer, trilayer, . . . sequence as T—+ Tc. The appearance of the first ten surface layers is described very well by the simple power-law form, L —Lot ~, predicted for the surface freezing transition in a system with van der Waals forces.