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Showing papers on "Hydrofluoric acid published in 1982"


Journal ArticleDOI
TL;DR: In this paper, the electrochemistries of antimony and simple hydrocarbons were examined in HF/SbF/sub 5/. From cyclic voltammetric data, Sb(V) appears to be a strong oxidizing agent in the super acid media, capable of oxidizing polymeric material containing three or more carbon atoms.
Abstract: The electrochemistries of antimony and simple hydrocarbons were examined in HF/SbF/sub 5/. From cyclic voltammetric data, Sb(V) appears to be a strong oxidizing agent in the super acid media, capable of oxidizing hydrocarbons containing three or more carbon atoms. It is therefore reasonable that the Sb(V) reduction process supplies the energy required for the super acid ''catalyzed'' condensation of saturated hydrocarbons, confirming suggestions already in the literature. The anodic oxidation of aromatic hydrocarbons was also examined in acidic fluoride media (HF/SbF/sub 5/ and HF/NaF). It is observed that the oxidation of benzene results in the deposition of electronicallyconducting polymeric material on the anode. The material has been identified as p-polyphenylene. The conductivity of the polymer is assumed to result from the formation of a charge-transfer complex between the partially oxidized polymer and the Lewis acid.

65 citations


Journal ArticleDOI
TL;DR: In this paper, the gravimetric method was used to study the reaction between fused silica and silicate glasses with HF acid solution, and the reaction was found to be transport-controlled.
Abstract: The gravimetric method was used to study the reaction between fused silica and silicate glasses with HF acid solution. The reaction was found to be transport-controlled. Additions of Al2O3, CaO, or both to fused silica caused a reduction in corrosion resistance of the resulting glasses.

58 citations


Journal ArticleDOI
TL;DR: A geochemical simulator that allows for mineral dissolution, precipitation, ion-pair complexation and flow with dispersion in a linear porous medium has been developed as mentioned in this paper, which is based on the thermodynamic equilibrium between aqueous species of the fluid phase and mineral assemblages of the solid phase.
Abstract: A geochemical simulator that allows for mineral dissolution, precipitation, ion-pair complexation and flow with dispersion in a linear porous medium has been developed. The calculations are based on the thermodynamic equilibrium between aqueous species of the fluid phase and mineral assemblages of the solid phase. The simulator has been used to study sandstone acidizing by use of hydrofluoric/hydrochloric (HF/HCl) acid mixtures and specifically to examine the permeability loss commonly encountered when formations are first contacted with these mixtures. Included were 30 different aqueous species and 14 possible mineral species. It was found that when acids are introduced into sandstone media containing aluminosilicate minerals, the formation of chemical precipitates takes place if a maximum allowable HF level for a given HCl level is exceeded. Further, the permeability losses attending the precipitation were shown to correlate with experimental observations. Model calculations confirmed the precipitation of colloidal silica, as proposed by others, and identified other, further complicating precipitates.

33 citations


Patent
30 Apr 1982
TL;DR: In this paper, Lubricating oils and aluminum fines are removed from aluminum surfaces by contacting the surfaces with an aqueous solution containing sulfuric acid, hydrofluoric acid, and an alkali metal 2-butoxyethoxyacetate anionic surfactant.
Abstract: Lubricating oils and aluminum fines are removed from aluminum surfaces by contacting the surfaces with an aqueous solution containing sulfuric acid, hydrofluoric acid, and an alkali metal 2-butoxyethoxyacetate anionic surfactant The solution may also contain one or more low foaming nonionic surfactants

25 citations


Patent
01 Mar 1982
TL;DR: In this paper, the aluminum oxide (Al2 O3) in fly ash with phosphoric acid was used to form aluminum phosphate, which was then converted to sodium aluminate by reaction with sodium hydroxide, and finally converted to cryolite (Na3 AlF6), or equivalent reagent providing H+ and F- ions.
Abstract: Cryolite (Na3 AlF6) as a source of aluminum is prepared from coal fly ash by reacting the aluminum oxide (Al2 O3) in fly ash with phosphoric acid to form aluminum phosphate, which is then converted to sodium aluminate by reaction with sodium hydroxide, and the sodium aluminate is converted to cryolite by reaction with hydrofluoric acid (HF), or equivalent reagent providing H+ and F- ions. Aluminum is thereby obtained from fly ash in a preferred form (as cryolite) for use in producing metallic aluminum.

25 citations


Journal ArticleDOI
TL;DR: Amorphous silicon containing carbon, hydrogen and fluorine were electrodeposited from solutions containing ethylene glycol, hydrofluoric acid, and tetraethyl orthosilicate or silicic acid as mentioned in this paper.

21 citations


Journal ArticleDOI
TL;DR: In this paper, the authors proposed a novel way to obtain approximate quantum mechanical differential cross sections, and they used this approximate method to study the reactions F + HD(nu = 0)..-->.. FH(nu' = 2) + D and F + DH(nu= 0), DF(nu') = 3) + H. Backward and forward scattering are found for the first reaction and only backward scattering for the second one.
Abstract: In a previous paper we proposed a novel way to obtain approximate quantum mechanical differential cross sections. Here, we use this approximate method to study the reactions F + HD(nu = 0) ..-->.. FH(nu' = 2) + D and F + DH(nu = 0) ..-->.. DF(nu' = 3) + H. Backward and forward scattering are found for the first reaction and only backward scattering for the second one. These results agree qualitatively with experiment. 1 figure.

20 citations


Journal ArticleDOI
TL;DR: Wood chips from bigtooth aspen were saccharified by reaction with liquid hydrogen fluoride either anhydrous or containing up to 10% v/v water, and glucosylfluoride was identified by its specific rotation and also by gas chromatography‐mass spectrometry of its tetra‐O‐trimethylsilyl derivative.
Abstract: Wood chips from bigtooth aspen (Populus grandidentata Michx.) were saccharified by reaction with hydrogen fluoride either anhydrous or containing up to 10% v/v water. The reaction products were separated into a solid lignin fraction and a water-soluble saccharide fraction. The fluoride content of the lignin (determined after alkaline fusion) was initially about 1 mg/g wood, but was lowered to 0.1 mg/g wood by grinding and washing. Thus little or no chemical binding of fluoride to lignin occurred during hydrogen fluoride (HF) solvolysis. Analysis of the water-soluble fraction by gel filtration on Biogel P2 columns showed a range of low-molecular-weight oligosaccharides an only 10-20% sugar monomers. Thus considerable reversion occurred during HF evacuation. Posthydrolysis conditions were optimized for these reversion products by varying temperature and acid concentration. Optimal conditions at 1 h were 140/sup 0/C with 100mN sulfuric acid or 225mN hydrofluoric acid resulting in monomer yields of > 90% for 0.5% sugar solutions and > 80% for 10% sugar solutions. After reaction of pure cellulose (filter paper) with hydrogen fluoride in the absence of water, and terminating the reaction with calcium carbonate, the reaction intermediate ..cap alpha..-D-glucopyranosylfluride was isolated with a maximal yield of 0.2 g/g paper. Upon purification viamore » paper chromatography glucosyfluoride was identified by its specific rotation and also by gas chromotography-mass spectrometer of its tetra-O-trimethylsilyl derivative.« less

18 citations



Patent
18 Mar 1982
TL;DR: In this article, an etching soln is used to form a satin pattern having many protrusions and recesses of >= about 0.2mm on the surface of glass by immersing the glass in an etch soln.
Abstract: PURPOSE:To form a satin pattern having many protrusions and recesses of >= about 0.2mm. on the surface of glass by immersing the glass in an etching soln. consisting of a specified amount of hydrofluoric acid, ammonium fluoride, hydrochloric acid, sulfuric acid, nitric acid and water and by applying movement, vibration or rotation to the glass or a flow, agitation or rotation to the soln. CONSTITUTION:An etching soln. is composed of 5-40% hydrofluoric acid, 16- 33% ammonium fluoride, 0-20% hydrochloric acid, 0-25% sulfuric acid, 0-35% nitric acid and 30-65% water. Glass is immersed in the etching soln., and movement, vibration or rotation is applied to the glass, or a flow, agitation or rotation to the soln. After a fixed time, the glass is pulled up and washed. The surface of the glass 10 thus treated is converted into a satin surface having many protrusions 11. The inclined planes 12 of the protrusions 11 are different from each other in gradient, and reflected rays 14 of light are not uniform to irradiated rays 13 and cause irregular reflection, so that glass surface shines brilliantly.

14 citations


Patent
02 Mar 1982
TL;DR: In this article, a method of recovering tantalum from silicon-containing tantalum scrap is described, which comprises dissolving said scrap in an inorganic acid, bringing the resulting solution into contact with an anionic exchange resin, followed by washing the same with an aqueous solution of a mixture composed of hydrofluoric acid, ammonia and an ammonium salt.
Abstract: Disclosed is method of recovering tantalum from silicon-containing tantalum scrap, which comprises dissolving said scrap in an inorganic acid, bringing the resulting solution into contact with an anionic exchange resin, followed by washing said anionic exchange resin with (a) a solution of 3 to 10 mol/l. of hydrofluoric acid or (b) a solution of strongly acidic medium containing 0.01 to 0.5 mol/l. of hydrofluoric acid and 1 to 6 mol/l. of a strong acid, and then washing the same with an aqueous solution of a mixture composed of hydrofluoric acid, aqueous ammonia and an ammonium salt.

Patent
Michel Desbois1
30 Jun 1982
TL;DR: In this paper, a halogen or acylation process trihalogenomethylbenzenes is described, where a carboxylic acid is used as a precursor or a derivative of this acid in the presence of boron trifluoride in such quantity that the absolute pressure in the reaction enclosure is greater than 1 bar.
Abstract: The invention relates to a halogen or acylation process trihalogenomethylbenzenes. According to this method, is reacted with halo or trihalomethylbenzene a carboxylic acid, a precursor or a derivative of this acid in the presence of boron trifluoride in such quantity that the absolute pressure of boron trifluoride in the reaction enclosure is greater than 1 bar and in the presence of hydrofluoric acid as solvent. The products obtained are useful as synthesis intermediates for compounds having phytosanitary or pharmaceutical activity.

Journal ArticleDOI
TL;DR: In this article, the effect of aqueous phase composition was studied in a factorial design test and also by varying the concentrations of the components individually over a range typical of their concentrations in wet-process phosphoric acid.
Abstract: Octylphenyl acid phosphate (OPAP) is a commercially available mixture of monooctylphenyl phosphoric acid (MOPPA) and dioctylphenyl phosphoric acid (DOPPA) that is used to extract U/sup IV/ from wet-process phosphoric acid. The uranium extraction coefficient and the organic phase iron loading were not affected by changes in the organic phase composition due to hydrolysis of the extractant or by different MOPPA/DOPPA ratios in two OPAP batches. The effect of aqueous phase composition was studied in a factorial design test and also by varying the concentrations of the components individually over a range typical of their concentrations in wet-process phosphoric acid. Uranium extraction was decreased by increasing the concentrations of total phosphate, ferric iron, hydrofluoric acid, or total sulfate, and increased by increasing the concentrations of aluminum, magnesium, or silicon. 6 refs.

Patent
16 Jun 1982
TL;DR: In this paper, Austrian stainless steels are etched with hydrogen fluoride and peroxides instead of hydrofluoric acid and nitric acid and the process is simpler and more environmentally compatible.
Abstract: Austenitic stainless steels are etched with hydrogen fluoride and peroxides instead of hydrofluoric acid and nitric acid. The process is simpler and more environmentally compatible.


Journal ArticleDOI
TL;DR: In this article, a simple rapid method for the routine determination of silica by atomic absorption spectrometry (a.a.s.) in a wide range of geological materials is described.

Patent
13 Sep 1982
TL;DR: In this article, the synthesis of a carboxylic acid by the carbonylation of an olefin in the presence of a catalytic catalytic catalyst is described.
Abstract: In the preparation of a carboxylic acid by the carbonylation of an olefin in the presence of hydrofluoric acid catalyst, the hydrofluoric acid is isolated from the carboxylic acid by means of an ion-permeable membrane and the thus-isolated hydrofluoric acid can be recycled to again catalyze the carbonylation reaction.

Journal ArticleDOI
TL;DR: In this article, a special infrared spectral profile with an intense band and two satellites on each side is observed for hydrogen fluoride hydrogen bonded to deuterium fluoride molecules in the solid state, and the sidebands are interpreted as the result of a combination of the FH stretching vibration with the stretching and bending modes of the hydrogen bond.
Abstract: A special infrared spectral profile with an intense band and two satellites on each side is observed for hydrogen fluoride hydrogen bonded to deuterium fluoride molecules in the solid state. The sidebands are interpreted as the result of a combination of the FH stretching vibration with the stretching and bending modes of the hydrogen bond⋅⋅⋅F–H⋅⋅⋅F. This interpretation is confirmed by the temperature dependence of the intensity of the sidebands. The experimental result also reveals a strong mechanical anharmonicity in the coupling between the high frequency vibration and the low frequency modes and a strong electrical anharmonicity of the hydrogen‐bond vibrations.

Patent
Michel Desbois1
28 Jun 1982
TL;DR: In this article, the authors describe a process for the acylation of halo- or trihalomethylbenzenes, where a halo or tri-halogen is reacted with a carboxylic acid, a precursor or a derivative thereof, in the presence of boron trifluoride in an amount such that the absolute pressure of the boronal trifluride within the reaction vessel exceeds 1 bar, and in the case of hydrofluoric acid as a solvent.
Abstract: A process for the acylation of halo- or trihalomethylbenzenes, wherein a halo- or trihalomethylbenzene is reacted with a carboxylic acid, a precursor or a derivative thereof in the presence of boron trifluoride in an amount such that the absolute pressure of the boron trifluoride within the reaction vessel exceeds 1 bar, and in the presence of hydrofluoric acid as a solvent. The resultant products are useful as intermediates in the synthesis of compounds having a phytosanitary (e.g., herbicidal) or pharmaceutical activity.

Patent
14 May 1982
TL;DR: Aromatic/aliphatic nitriles having the formula: Ar--A--CN (I) wherein Ar is phenyl or substituted phenyl and A is a direct chemical bond or a hydrocarbon having from 1 to 6 carbon atoms, are conveniently prepared by heating to a temperature ranging from about 450° C. to about 550° C as discussed by the authors.
Abstract: Aromatic/aliphatic nitriles having the formula: Ar--A--CN (I) wherein Ar is phenyl or substituted phenyl and A is a direct chemical bond or a hydrocarbon having from 1 to 6 carbon atoms, are conveniently prepared by heating to a temperature ranging from about 450° C. to about 550° C. a formamide or formanilide having the formula: Ar--A--NHCHO (II) or an amide having the formula: Ar--A--CONH 2 (III) in the presence of a fluorinated siliceous catalyst, said catalyst having been prepared by (i) impregnating a particulate silica prepared by the precipitation of sodium silicate with sulfuric acid, with a dilute aqueous solution of hydrofluoric acid, said hydrofluoric acid solution having a concentration in HF of less than about 5% by weight, and the ratio by weight of the hydrofluoric acid contained in said aqueous solution thereof to the silica being less than about 5%, followed by (ii) drying the catalyst thus impregnated.

Patent
Michel Desbois1
30 Jun 1982
TL;DR: In this paper, a method for preparing a, a-difluoroalkoxy or a-a-diffluoro-alkylthiophenylcetones was proposed, which is useful as synthesis intermediates for compounds having phytosanitary or pharmaceutical activity.
Abstract: The invention relates to a process for preparing a, a-difluoroalkoxy or a, a-difluoroalkylthiophenylcetones. According to this method comprises reacting a polyhalogenoalkoxybenzene polyhalogenoalkylthiobenzene or with a carboxylic acid, a precursor or a derivative of this acid in the presence of boron trifluoride in such quantity that the absolute pressure of boron trifluoride in the reaction enclosure is greater than 1 bar and in the presence of hydrofluoric acid as solvent. The products obtained are useful as synthesis intermediates for compounds having phytosanitary or pharmaceutical activity.

Patent
16 Jan 1982
TL;DR: In this article, a plated polyamide article having strong adhesion to metal films, a low dispersion in adhesive force and excellent surface luster was produced by immersing it in an aqueous borohydrofluoric acid solution, 10-30% concentration, or in hydrofluoric acids at 20-50 degC for 5-30min.
Abstract: PURPOSE:To obtain a molded product having excellent adhesion to metal films, by treating a polyamide molding with a solvent having a dissolving power for polyamides and, then, etching the product with (boro)hydrofluoric acid CONSTITUTION:A polyamide molding obtained by molding a polyamide or a composition containing 100ptswt polyamide and 10-200ptswt inorganic filler, particle size 02-20mu, is immersed in a polyamide-dissolving mineral acid, organic acid or organic solvent, eg, sulfuric acid, formic acid, methanol, at 20-60 degC for 1-30min, and etched by immersing it in an aqueous borohydrofluoric acid solution, 10-30wt% concentration, or in hydrofluoric acid at 20-50 degC for 5-30min EFFECT:It is possible to produce plated polyamide articles having strong adhesion to metal films, a low dispersion in adhesive force and excellent surface luster

Journal ArticleDOI
TL;DR: In this paper, a new cation exchange method for the mutual separation of metals which form stable fluoride complexes has been developed using hydrofluoric-boric acid media, which reduces the free fluoride ion concentration to about one hundredth because of the formation of fluoroboric acid.
Abstract: Using hydrofluoric–boric acid media, a new cation exchange method for the mutual separation of metals which form stable fluoride complexes has been developed. The addition of boric acid to a hydrofluoric acid solution reduces the free fluoride ion concentration to about one hundredth because of the formation of fluoroboric acid. This reduction of the free fluoride ion concentration makes it easy to control the formation of metal fluoride complexes, favoring their separation. As the fluoroboric acid has a buffer action relating to the fluoride ion concentration, the distribution coefficients of metal ions are not affected by the increase in the concentrations of metal ions, even at a low concentration of fluoride ions in the solution. By the use of hydrofluoric–boric acid media, such metals as zirconium, titanium, aluminium, and uranium can be separated from each other. The distribution coefficients of eighteen metals were investigated both in hydrofluoric acid and hydrofluoric–boric acid solutions.

Journal ArticleDOI
TL;DR: In this paper, the minor components Al, Sn, Zr, Mo, V, Mn and Si are determined by their atomic emission in the plasma, after the hydrofluoric acid has been masked with boric acid.

Patent
06 Sep 1982
TL;DR: In this article, a weak basic anion exchange (SBE) resin was used to remove silicic acid selectively and to reduce the cost for production of ultrapure water.
Abstract: PURPOSE:To remove silicic acid selectively and to reduce the cost for production of ultrapure water by passing water contg. silicic acid through a weak basic anion exchange resin adsorbed with hydrofluoric acid. CONSTITUTION:Mineral acid 10 is added to pretreated raw water 9 to turn carbonic acid ions to free carbonic acid which is beforehand removed with a decarboxylation device 1. Thence, it is passed through a silicic acid adsorption tower 2 packed with a weak basic anion exchange resin adsorbed with hydrofluoric acid, following to which it is passed through a W-OH tower 4 packed with an OH type weak basic anion exchange resin 3', whereby the amt. of the leaking silicic acid and fluorine is reduced. The raw water 9' removed of the silicic acid is passed through a reverse osmosis membrane device 5, and a large amt. of the resultant permeated water 11 is passed through a mixed bed type water purifying device 6, whereby pure water 12 is obtd. The pure water 12 is subjected to precision filtration treatment, sterilization treatment and polisher treatment, whereby the ultrapure water is produced.

Journal ArticleDOI
TL;DR: In this paper, a new solid fluoroperoxo complex of vanadium(V) has been synthesized under high acidity conditions, starting from vanadium pentoxide, hydrofluoric acid and hydrogen peroxide.
Abstract: A new solid fluoroperoxo complex of vanadium(V) has been synthesised under high acidity conditions, starting from vanadium pentoxide, hydrofluoric acid and hydrogen peroxide. The dried solid has potassium, vanadium, peroxide and fluorine in the molar ratio 1.1:1.0:1.0:1.0. The infrared and laser Raman spectra show characteristic absorption bands due to the vanadyl moiety and the bridged V-O-V species.

Journal ArticleDOI
TL;DR: In this paper, the determination of nitrogen in zirconium by chargedparticle activation analysis is described, where the 14N(α,αn)13N and the 14 n(p,α)11C reactions were used.
Abstract: The determination of nitrogen in zirconium by charged-particle activation analysis is described. The14N(α,αn)13N and the14N(p,α)11C reactions were used. The13N activity was separated from matrix activity as ammonia by steam-distillation after dissolution of the sample in dilute hydrofluoric acid. The11C activity was separated as carbon dioxide by dissolution of the sample in a mixture of concentrated sulphuric acid, sodium fluoride and potassium periodate, followed by oxidation of the evolved gases with a copper oxideiron oxide-kaolin mixture and trapping of the carbon dioxide in dilute sodium hydroxide solution. The chemical yield of both separations was investigated. The nuclear interference of boron can be neglected, in view of the low boron content. Alpha- and proton-activation yielded the following results for BCR reference materials (alpha-activation results first): CRM 21: 24.6±3.3 and 25.9±0.8μg/g (certified value: 26.4±2.5μg/g); CRM 56: 12.0±1.1 and 10.5±0.3μg/g (certified value: 11.7±1.7μg/g); CRM 57: 11.2±0.3μg/g (alpha-activation) (certified value: 11.9±1.8μg/g).

Patent
09 Nov 1982
TL;DR: In this article, an aqueous solution having a phosphoric acid concentration in the range of from about 10 to about 30% by weight, to which is added at least one fluorine donor compound in an amount to provide a generated hydrofluoric acid content in a range from about 1 to about 7%.
Abstract: A composition for treatment of siliceous formations, comprising an aqueous solution having a phosphoric acid concentration in the range of from about 10 to about 30% by weight, to which is added at least one fluorine donor compound in an amount to provide a generated hydrofluoric acid concentration in the range of from about 1 to about 7% by weight. The composition is quite reactive towards clay and silica but, unlike conventional mud acid, displays significantly retarded reactivity towards calcium carbonate. The preferred fluorine donor is ammonium bifluoride, and an especially effective phosphoric acid solution is a Turflo® solution, components of which serve to further potentiate calcium carbonate reactivity retardation.

Patent
22 Jul 1982
TL;DR: In this article, a thin film consisting essentially of chromium and phosphatized compd is applied on the surface of an amorphous alloy and drying and baking the coating.
Abstract: PURPOSE:To form a dense thin film consisting essentially of chromium and phosphatized compd. by coating an aq. acidic soln. contg. a chromic acid, phosphoric acid and fluorine compd. on the surface of an amorphous alloy and drying and baking the coating. CONSTITUTION:An aq. acidic soln. prepd. by contg. about 0.01-2g ion/l chromic acid in terms of Cr, and about 0.01-0.1g equiv./l fluorine compd. such as hydrofluoric acid in terms of F, and adding a phosphoric acid there to make pH about 0.5-3 is coated on the surface of an amorphous alloy obtd. by cooling ultra- quickly the melt of an alloy formed by contg. about 70-80atom% sum total of Fe, Co and Ni, about 7-25% B, and the balance Si, P, and C and adding about <=5% Cr, Mo, Nb, V, etc. in some case on a cooling base plate and after the coating is dried by hot air, the coating is baked at about 150-250 deg.C to form a film having about 0.001-0.2mu film thickness. The treated film adheres densely and securely to the underlying amorphous alloy, has an excellent insulating characteristic and corrosion resistance and has excellent performance to prevent aging of the magnetism owing to the change of the surface characteristic.

Journal ArticleDOI
TL;DR: In this paper, the properties of HF-H3BO3 media and the distribution coefficients of eighteen metals have been investigated to achieve the separation of hard acid-metals by the anion exchange method.
Abstract: The properties of HF–H3BO3 media and the distribution coefficients of eighteen metals have been investigated to achieve the separation of hard acid-metals by the anion exchange method. As the addition of boric acid to hydrofluoric acid solution reduces the free fluoride ion concentration to about one hundredth, it is possible to control the formation of metal fluoride complexes in a way favorable for the separation. The BF4− and BF3OH− produced in this media are adsorbed strongly to the resin and reduce the relative adsorbabilities of metal fluoride complexes remarkably. Using these properties of HF–H3BO3 media and the adsorbabilities of other anions, a new anion exchange method for the separation of hard acid-metals has been proposed. The new method is especially useful for the separation of titanium, zirconium, niobium, and tantalum. Distribution coefficients and elution behaviors of metal ions are not affected by the increase of the amount of metals because of the buffer action relating to the fluoride...