Showing papers on "Lewis acids and bases published in 1979"
TL;DR: The infrared spectra of the H-ZSM-5 zeolite calcined at temperatures up to 1173 K, and the corresponding electron spin resonance and microcalorimetric data are discussed in this paper.
287 citations
TL;DR: An IR spectroscopic study of the reduction of copper-exchanged Linde Na-Y zeolite with hydrogen or carbon monoxide and oxidation with oxygen or oxygen-18 showed that copper(I) and AlO(+1) are formed during reduction, and that oxidation generates copper(II) ions but does not change the aluminum species as mentioned in this paper.
Abstract: An IR spectroscopic study of the reduction of copper-exchanged Linde Na-Y zeolite with hydrogen or carbon monoxide and oxidation with oxygen or oxygen-18 showed that copper(I) and AlO(+1) are formed during reduction, and that oxidation generates copper(II) ions but does not change the aluminum species. Trigonally coordinated aluminum was not detected.
194 citations
TL;DR: In this article, a series of complex structures were assigned a dimeric structure on the basis of 1H and 13C n.m.r. data, and by crystal and molecular structural determinations of [{M(η-C5H5)2Me}2] and pyridine.
Abstract: The reaction of [(η-C5H5)2MMe2AlMe2](M = Y, Dy, Ho, Er, Tm, or Yb) and pyridine in equimolar amounts gives a series of complexes [{M(η-C5H5)2Me}2] assigned a dimeric structure on the basis of 1H and 13C n.m.r. (M = Y) and i.r. data, and by crystal and molecular structural determinations of [{M(η-C5H5)2Me}2](M = Y or Yb). A similar reaction of [(η-C5H5)2ScMe2AlMe2] with a Lewis base L gives [Sc(η-C5H5)2Me(L)](L = pyridine or tetrahydrofuran). Other reactions described are of [{Y(η-C5H5)2Me}2] with Lewis bases (an amine, phosphine, or phosphine oxide) or with a Lewis acid [Al2MenCl6 –n](n= 2, 4, or 6). A single-crystal X-ray analysis of the isostructural [{M(η-C5H5)2Me}2] has been carried out to R 0.048 (Y) or 0.066 (Yb) and R′ 0.055 (Y) or 0.061 (Yb); the complexes have an approximately tetrahedral metal environment (space group P21/n) with the YMe2Y unit in the yttrium complex remarkably similar to AlMe2Al in [Al2Me6]. Important average bond lengths (A) and angles for the yttrium complex (Yb in parentheses) are: Y–C (cyclopentadienyl) 2.655(18)[2.613(13)] and Y–Me 2.545(11)[2.511(35)]; Y–C–Y 87.7(3)[86.6(3)] and Me–Y–Me 92.3(3)[93.4(4)].
112 citations
103 citations
TL;DR: The capacity of cyclopentadienylsodium to form adducts with the following bases has been studied: diethyl ether, tetrahydrofuran, 1,2-dimethoxyethane, 1 4-dioxane, benzo-15-crown-5, triethylamine, tetramehtylethylenediamine, pyridine, 4-dimethylaminopyridine and 2,2′ bipyridryl Most form extremely air-and moisture-sensitive 1 : 1 adduct
81 citations
TL;DR: In this paper, the infrared spectra of Fe 2 O 3, ZnO, MoO 3, and V 2 O 5 were investigated before and after the adsorption of ammonia at 20 °C and after its desorption at room and higher temperatures.
76 citations
74 citations
TL;DR: In this article, the thermal intercalation of pyridine with 2H-TaS2 is associated with redox reactions involving guest layers and host molecules, and the reaction product is discussed in terms of a novel ionic bonding concept.
65 citations
Patent•
26 Mar 1979TL;DR: A component of a polymerization catalyst is prepared by reacting an organo-magnesium halide with a solid, inorganic oxide, then reacting the product with a Lewis Base compound, particularly an ester and finally with titanium tetrachloride.
Abstract: A component of a polymerization catalyst is prepared by reacting an organo-magnesium halide with a solid, inorganic oxide, then reacting the product with a Lewis Base compound, particularly an ester and finally with titanium tetrachloride. After reacting the organo-magnesium halide with the inorganic oxide it may be treated with a halogenating agent before it is reacted with the Lewis Base compound. The product obtained is combined with an organo-aluminium compound preferably together with a Lewis Base and used to polymerize an olefine monomer. The catalyst has a high activity, is stereospecific and has a lower proportion of halogen than some other catalyst systems.
52 citations
TL;DR: The reaction of 2-(trimethylsiloxy)furan (1) with orthocarboxylic esters, acetals, and acylal in the presence of Lewis acids afforded the corresponding 4-substituted 2-buten-4-olides as mentioned in this paper.
Abstract: The reaction of 2-(trimethylsiloxy)furan (1) with orthocarboxylic esters, acetals, and acylal in the presence of Lewis acids afforded the corresponding 4-substituted 2-buten-4-olides. The reaction of 5-methyl-2-(trimethyl-siloxy)furan with orthocarboxylic esters gave unstable 2-substituted 3-penten-4-olides as major products; these gave 2,5-alkanediones upon hydrolysis. The furan (1) also reacted with 1,1-diacetoxy-2-butene to give a mixture of 5-acetoxy-2,6-octadien-4-olide and 7-acetoxy-5-methyl-2,6-heptadien-4-olide. From the former compound, nigrosporalactone was synthesized.
TL;DR: In this article, a one-pot preparation of α,β,unsaturated nitriles from ketones with trimethylsilyl cyanide in benzene in the presence of a Lewis acid (ZnI2) as a catalyst and subsequent heating after addition of pyridine and phosphoryl chloride has been presented.
Abstract: Treatment of ketones with trimethylsilyl cyanide in benzene in the presence of a Lewis acid (ZnI2) as a catalyst and subsequent heating after addition of pyridine and phosphoryl chloride have given α,β,-unsaturated nitriles in good yields, providing a general one-pot preparation of α,β,-unsaturated nitriles from ketones.
Patent•
31 Oct 1979TL;DR: In this paper, the authors describe a catalyst which is homogeneously soluble in solvents for the polymerization of dienes, obtained by adding the catalyst constituents to the polymerisation mixture and mixing them therewith, consisting of : A) a rare earth carboxylate of the formula see diagramm : EP0011184,P8,F1 B) an aluminium alkyl AIR3 **4 and/or R2 **4AIH and C) a further Lewis acid, wherein in the formulae M denotes a trivalent rare earth
Abstract: 1. A catalyst which is homogeneously soluble in solvents for the polymerisation of dienes, obtained by adding the catalyst constituents to the polymerisation mixture and mixing them therewith, consisting of : A) a rare earth carboxylate of the formula see diagramm : EP0011184,P8,F1 B) an aluminium alkyl AIR3 **4 and/or R2 **4AIH and C) a further Lewis acid, wherein in the formulae M denotes a trivalent rare earth element having an atomic number of from 57 to 71, R**1, R**2 and R**3 are identical or different and denote alkyl radicals with 1 to 10 carbon atoms, the sum of all the C atoms in the substituents being from 6 to 20,and R**4 denotes an alkyl radical with 1 to 10 carbon atoms, with the exception of a catalyst which contains a reaction product of component A of the formula 1, wherein the sum of all the C atoms in the substituents is from 6 to 19, with a portion of component B, when B has the meaning aluminium trialkyl.
TL;DR: The action of Lewis acids on aryl-t-butyloxetans (1) yields substituted tetrahydrofurans (4) or oxetan ring cleavage products; both are believed to be formed via carbocationic intermediates.
Abstract: The action of Lewis acids on aryl-t-butyloxetans (1) yields substituted tetrahydrofurans (4) or oxetan ring cleavage products; both are believed to be formed via carbocationic intermediates.
TL;DR: In this article, reaction of a series of aniline derivatives with chlorosulphonyl isocyanate followed by cyclisation of the resulting chlorosulo-phonylureas with Lewis acids gives good yields of 2H-1,2,4-benzothiazidazin-3(4H)-one 1,1-dioxides.
Abstract: Reaction of a series of aniline derivatives with chlorosulphonyl isocyanate followed by cyclisation of the resulting chlorosulphonylureas with Lewis acids gives good yields of 2H-1,2,4-benzothiazidazin-3(4H)-one 1,1-dioxides. These, upon acid hydrolysis, yield the corresponding o-aminobenzenesulphonamides.
Patent•
25 Jan 1979TL;DR: In this article, a process for preparing a catalytic solution of a sulfonium salt of a complex anion capable of yielding a Lewis acid when irradiated by UV or high energy ionizing radiation is described.
Abstract: This invention relates to a process for preparing a catalytic solution of a sulfonium salt of a complex anion, capable of yielding a Lewis Acid when irradiated by UV or high energy ionizing radiation comprising reacting a sulfonium halide with an alkali metal salt of the complex anion in a solvent mixture containing a polyol having at least two hydroxy groups and a lactone.
Patent•
18 Oct 1979
TL;DR: In this paper, a process for producing oxymorphone by converting oxycodone utilizing a suitable boron reagent in the presence of a weak Lewis base attenuating agent is described.
Abstract: A process for producing oxymorphone by converting oxycodone utilizing a suitable boron reagent in the presence of a weak Lewis base attenuating agent.
TL;DR: In this article, allylations of various carbon electrophiles such as carbonyl compounds, acetals, and α,β-enones with allylstannanes promoted by bis(diethylaluminum)sulfate or boron trifluoride etherate are described.
Abstract: Allylations of various carbon electrophiles such as carbonyl compounds, acetals, and α,β-enones with allylstannanes promoted by bis(diethylaluminum)sulfate or boron trifluoride etherate are described. Merits and demerits of using allylstannanes in syntheses instead of allylsilanes are also discussed.
Patent•
02 Jan 1979
TL;DR: In this paper, an improvement is provided wherein the catalyst further comprises 0.02 to 2 moles of a nucleophilic substance which acts as a Lewis base for the Lewis acid.
Abstract: In a process for the manufacture of a heat-stable, nuclear-brominated polystyrene by brominating, at -20° C. to +40° C., a polystyrene dissolved in a chlorinated hydrocarbon in the presence of a Lewis acid catalyst, an improvement is provided wherein the catalyst further comprises 0.02 to 2 moles, per mole of Lewis acid, of a nucleophilic substance which acts as a Lewis base for the Lewis acid.
TL;DR: In this article, a new way to vinylic ethers from acetals from a Lewis acid (aluminium chloride or magnesium bromide) with tertiary amine was proposed, corresponding to the elimination of one molecule of alcohol.
Abstract: A new way to vinylic ethers from acetals
Acetals react at low temperatures in presence of a Lewis acid (aluminium chloride or magnesium bromide) with tertiary amine to give in good yields the vinylic ethers corresponding to the elimination of one molecule of alcohol.
Patent•
09 Mar 1979TL;DR: In this paper, a trifluoromethylation of aromatic compounds via carbon tetrachloride and hydrogen fluoride in the presence of strong Bronsted or Lewis acids is described.
Abstract: This invention relates to a novel process for the direct trifluoromethylation of aromatic compounds via carbon tetrachloride and hydrogen fluoride in the presence of strong Bronsted or Lewis acids which give an acidic reaction (increase in concentration of H 2 F + ions) in anhydrous hydrogen fluoride.
TL;DR: In this article, a triacoordinated neutral dialkylaminosulphur (IV)-oxidefluorides, R2N S (O)F, and amino-imino sulphur(IV)fluoride, R 2N S (=NRf)F gave three-coordinated sulphur cations [R2N O]-] or [R 2 N NRf]+.
TL;DR: In this article, the authors show that adding any Lewis base to the alkenyltitanium intermediate induces decomposition of this intermediate to give an alkene by hydrogen atom abstraction from the medium, with loss of stereochemistry.
TL;DR: The dianion of methyl acetoacetate is alkylated at the γ-carbon with homoallylic bromides as mentioned in this paper, and the resulting alkenes are epoxidized and then cyclized with a Lewis acid to produce esters of 6,8-dioxabic...
Abstract: The dianion of methyl acetoacetate is alkylated at the γ-carbon with homoallylic bromides. The resulting alkenes are epoxidized and then cyclized with a Lewis acid to produce esters of 6,8-dioxabic...
TL;DR: In this article, the interaction of cobalt phthalocyanine with ammonia and oxygen in solutions of DMF was studied and the products investigated by e.s.r. signals showing the appropriate 14 N superhyperfine (s.h.f.) splitting.
TL;DR: In this article, Li/5M S cells were characterized with regard to capacity, rate, and rechargeability, showing that 75% cathode utilization is possible at 4 mA/cm2 (C/3-C/4 rate).
Abstract: Prototype cells of the configuration Li/~5M S as , THF, have been characterized with regard to capacity, rate, and rechargeability. Virtually 100% of the theoretical capacity could be realized at 50°C at rates below 1.0 mA/cm2. In high rate cell configurations, 75% cathode utilization is possible at ~4 mA/cm2 (C/3–C/4 rate). The capacities at high rate are enhanced by Lewis acids, although the ultimate cause of rate limitation is passivation of the current collector by discharge products. The self‐discharge rates of Li in contact with 4–5M S (as ) solutions reveal capacity losses of 0.5%/day at 25°C to 4.4%/day at 71°C. Based on the experimental results, a practical energy density of ~300 W‐hr kg−1 is possible using a standard cell design. Results on the battery's rechargeability are briefly reviewed.
TL;DR: In this article, the kinetic behavior suggests that the so-called sodium perborate is not peroxoborate but borate peroxyhydrate, H2O2 acquiring stronger electrophilicity by the coordination with boric acid which acts as Lewis acid rather than protic acid.
Abstract: Perborate oxidation of p-chloroaniline to 4,4′-dichloroazobenzene and H2O2–boric acid hydroxylation of aromatics have been studied. The kinetic behavior suggests that the so-called sodium perborate is not peroxoborate but borate peroxyhydrate, H2O2 acquiring stronger electrophilicity by the coordination with boric acid which acts as Lewis acid rather than protic acid.