Showing papers on "Ammonium hydroxide published in 1994"

Recovery of oligonucleotides by gas phase cleavage

Abstract: A process for the cleavage and deprotection of newly synthesized oligonucleotides from solid supports, which involves incubating the solid support in an environment comprising gaseous cleavage/deprotection reagent such as gaseous ammonia or ammonium hydroxide vapors. The method lends itself well to the use of supports such as microtiter plates, that can be used to simultaneously perform up to 96 individual synthetic processes.

Solution decontamination method using precipitation and flocculation techniques.

Abstract: Solutions such as for example groundwater, drinking water, extracting solutions and effluents contaminated with metals, radioactive species and organics, singly or in combination, are treated by first removing undesirable oxidizing agents from the contaminated solution. Then the contaminated solution is separately treated with aqueous solutions of ferrous sulfate and hydroxide, which precipitate substantially all of the contaminants. Next, the precipitate is treated with a flocculant and/or a coagulant to form an easily dewaterable and separable solid. The solid contaminants are readily removed from the cleansed solution. The process utilizes a novel combination of steps which maximizes contaminant removal, minimizes waste volume, and produces a recyclable solution and a manageable waste stream. The preferred hydroxide solutions are sodium hydroxide, calcium hydroxide, and ammonium hydroxide.

Process for preparing amorphous, catalytically active silico-aluminas

Abstract: An amorphous, micro/mesoporous silica-alumina gel with controlled pore size, having a surface area of at least 500 m2 /g and with a molar ratio of SiO2 :Al2 O3 of at least 30:1, is prepared by hydrolysing and causing a tetra-alkyl ammonium hydroxide, an aluminum trialkoxide, and a tetra-alkyl orthosilicate to gelate, by operating at a temperature equal to, or higher than, the boiling temperature, under atmospheric pressure, of any alcohols which are developed as a by-product from said hydrolysis reaction, without said alcohols being removed, or being substantially removed, from the reaction media; and the so produced gel being dried and fired. So obtained gel is an active catalyst in hydrocarbon conversion reactions, in particular in light olefin isomerization and oligomerization processes, e.g., in propylene oligomerization processes to yield useful liquid hydrocarbons for gasoline and jet fuel formulation.

Aspartic acid copolymers and their preparation

Abstract: Aspartic acid precursors such as mono and diammonium maleate, maleamic acid, ammonium maleamate, ammonium malate and mixtures of these and other precursors are copolycondensed thermally with a variety of mono, di and multifunctional monomers containing amino, hydroxyl and carboxyl functional groups. The resulting condensation copolymers and terpolymers contain succinimide units derived from aspartic acid precursors, condensed with other functional group monomers usually though amide and ester linkages. Hydrolysis of the polysuccinimide copolymers and terpolymers with alkali, alkaline earth and ammonium hydroxide produces aspartic acid copolymer and terpolymer salts.

Method of cleaning semiconductor substrate using an aqueous acid solution

Abstract: Cleaning methods for semiconductor substrates which can remove metallic impurities and natural oxide films from the surface of the substrate. As a cleaning solution, aqueous acid solution containing 0.0001-0.001 weight % of ammonia based on a conversion off the amount off ammonium hydroxide or 0.0005-0.01 weight % of EDTA is used. The cleaning solution preferably contains 1-10 weight % of hydrogen fluoride. Metallic impurities removed from the surface of the substrate into the cleaning solution form complexes or chelates with ammonia molecules or EDTA molecules, thereby masking the metallic impurities.

Fabrication of Vertical Sidewalls by Anisotropic Etching of Silicon (100) Wafers

Abstract: Silicon bulk micromachining using anisotropic etching has become an established method for producing micromechanical structures in silicon. Commercial applications for micromachining include pressures sensors, accelerometers optical spectrometers, and ink jet nozzles. Typically, silicon (111) planes etch at a much slower rate than (100) planes in certain etchants. These included potassium hydroxide (KOH), ethylene diamine pyrocatechol (EDP), sodium hydroxide (NaOH), ammonium hydroxide (NH 4 OH), cesium hydroxide (CsOH), tetramethyl ammonium hydroxide (TMAH), and hydrazine (N 2 H 4 )

Process and apparatus for semiconductor device fabrication

Abstract: A method and apparatus for cleaning substrates in a process for device fabrication is disclosed. An aqueous solution of hydrogen peroxide and ammonium hydroxide is used to clean the substrates. The concentration of hydrogen peroxide and ammonium hydroxide in the cleaning solution is maintained at a certain level. The life of the cleaning solution is extended by the process. By maintaining the concentrations of the hydrogen peroxide and ammonium hydroxide in the solution within a desired range, the process also provides a cleaning solution that effectively cleans the substates throughout the entire time the solution is used to clean the substrates. The apparatus monitors certain solution parameters such as the pH and the conductivity of the cleaning solution and adds hydrogen peroxide and/or ammonium hydroxide to the cleaning solution to maintain the parameters, and thus the concentration of hydrogen peroxide and ammonium hydroxide, at desired levels.

Etching of Thermally Grown SiO2 by NH4OH in Mixture of NH4OH and H2O2 Cleaning Solution.

Abstract: We have investigated the etching behavior of thermally grown SiO2 by ammonium hydroxide ( NH4OH) in NH4OH?H2O2?H2O cleaning solution (SC-1). The SiO2 etching rate increases with increasing impurity (boron or phosphorus) concentration in the SiO2 as well as concentration of NH4OH and temperature of SC-1 solution. Moreover, postoxidation SC-1 treatment with a low concentration of NH4OH (less than 3.15 wt% of NH4OH) does not degrade or improve oxide reliability. These indicate that if SC-1 treatment, which is performed after post-thin-oxide ( ?20 nm) or high-impurity-doped Si oxide formation, is carried out in ULSI device fabrication processes, SC-1 with low temperature and low NH4OH concentration must be applied after those processes to minimize SiO2 thickness reduction and preserve oxide reliability.

Solution decontamination method using precipitation techniques

Abstract: Solutions such as for example drinking water, ground water and extracting solutions contaminated with heavy metals and radioactive species, singly or in combination, are treated by first treating the contaminated solution with silicate and ammonium hydroxide solution precipitants. Then the contaminated solution is separately treated with an acid which gels, polymerizes and/or precipitates the contaminant-containing silica matrix to form an easily dewaterable and separable solid. The solid contaminants are readily removed from the cleansed solution by filtration means. The process utilizes a novel combination of steps which maximizes contaminant removal, minimizes waste volume, and produces a treatable waste solid. The preferred precipitants are sodium silicate, and ammonium hydroxide. The preferred mineral acid is hydrochloric acid.

Process for producing potassium carbonate

Abstract: A method for producing potassium carbonate using a continuous countercurrent exchange system. A continuous ion exchange system with resin in the ammonium form is flushed with a saturated potassium chloride solution which displaces the ammonium ion and replaces it with potassium. Ammonium carbonate is then passed through the ion exchanger to place the ammonium in the reserve form, by displacing the potassium, and produce a concentrated potassium carbonate solution. This process is done in a continuous countercurrent manner which allows maximum recovery of the potassium carbonate as a 15-18% by weight solution with minimum impurities, and at high throughput rates. The potassium carbonate solution is then removed, evaporated, dried, sized and stored for subsequent shipment. The ammonium chloride from the ion exchanger is treated with slaked lime to produce ammonium hydroxide, which in turn is reacted with carbon dioxide (from calcined limestone or an outside source) to regenerate ammonium carbonate for reuse in the ion exchanger. Calcium chloride is a co-product of the overall reaction.

Platinoid electrode catalyst and its manufacture

Abstract: PURPOSE: To provide the platinum alloy electrode catalyst having the activity equal to or more than that of a conventional one, and having high durability, by making the Pt-Ni-Co ternary alloy particles having a regular structure be carried on a conductive carrier. CONSTITUTION: A 10% ammonium hydroxide aqueous solution is added to 20ml of an aqueous solution containing respectively less than 1.54mm mol of nickel formate and cobalt acetate till pH becomes 10. The mixture liquid is added to 6g of platinum carbon catalyst in which 10wt.% of platinum metallic fine particles having about 140m /g of metallic specific surface area are carried on an acetylene carbon carrier having 100m /g of a specific surface area, and is sufficiently mixed. The slurry is evaporated, solidified in dry, pulverized, and reduced for 30 minutes at 250 deg.C in 10% hydrogen (the rest is nitrogen) gas flow, to reduce the nickel salt and the cobalt salt, and further the temperature is raised to 650 deg.C and is kept for 10 hours to regularly alloy Pt, Ni and Co.

Developer solution for acitinic ray sensitive resist

Abstract: Disclosed is a novel aqueous developer solution used in the development treatment of an actinic ray-sensitive resist for the manufacture of, for example, semiconductor devices, which is capable of giving a patterned resist layer free from the troubles of film residue or scum deposition in any finest patterning. The developer solution contains, in addition to a nitrogen-containing organic basic compound, e.g., tetramethyl ammonium hydroxide, dissolved in an aqueous medium as the solvent, an anionic surface active agent which is a diphenyl ether compound having at least one ammonium sulfonate group, such as an ammonium alkyl diphenylether sulfonate, in a concentration of 0.05 to 5% by weight.

Determination of Hexavalent Chromium in Environmental Fly Ash Samples by an Inductively Coupled Plasma-Atomic Emission Spectrometer with Ammonium Ion Complexation:

Abstract: A method to determine hexavalent chromium in environmental solid waste has been developed by using an ammonium complexation technique in ICP-AES. This method consists of a two-step extraction and the complexation of ammonium ion. An ammonium hydroxide solution was used to extract the chromium(VI) out of the fly ash sample into the solution. Interfering metal ions, such as Pb, Fe, and Zn in the fly ash sample, were effectively removed by extracting them as diethyldithio-carbamate (DDTC) complexes at pH 9.5 into an MIBK (methyl isobutyl ketone) solution. The pH of the aqueous phase of the sample is then transferred and adjusted to 6.0, and the Cr(VI) is extracted as its complex with MIBK prior to the organic ICP analysis. A method detection limit of 50 ng/g or better, as well as spike recoveries of 90 to 110% (at a spike concentration level of 500 ng/g), is obtained when this method is applied to determine chromium(VI) in fly ash samples.

Ilmenite processing using cold milling

Abstract: High energy ball milling of particulate ilmenite (or other titaniferous ore) at room temperature, for periods of up to 300 hours, in the presence of a suitable additive, produces a nanostructural powder from which at least a major proportion of the iron in the titaniferous ore can be leached. The additive may be a reducing agent (for example, amorphous boron), a long chained hydrocarbon (for example, dodecane) or a surfactant (preferably dihexadecy1 dimethyl ammonium acetate, or didodecyl dimethyl ammonium bromide, or didodecyl dimethyl ammonium acetate, or didodecyl dimethyl ammonium hydroxide, or sodium didodecyl sulphate). The leaching is preferably effected using 4M hydrochloric acid at a temperature of from 80 °C to 100 °C.

Simultaneous determination of seven trace impurities (Al, As, Cr, Fe, Ti, V and Zr) in high-purity nickel metal and nickel oxide by coprecipitation and inductively coupled plasma-atomic emission spectrometry

Abstract: Nickel is not coprecipitated with lanthanum hydroxide in ammonium hydroxide solution because it forms rapidly soluble nickel ammine complexes. This behaviour is used for the separation of Ni matrix from trace elements. These are simultaneously and quantitatively coprecipitated with lanthanum hydroxide at pH 10.0 and separated from the Ni matrix. Seven trace elements (Al, As, Cr, Fe, Ti, V and Zr) in Ni metal and 3 certified elements (Cr, Fe and Ti) in a standard reference material of nickel oxide have been simultaneously determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES).

Process for recovering dicarboxylic acid with reduced impurities from polyester polymer

Abstract: Technology for recycling polymers, such as polyethylene terephthalate (PET), is increasingly important in reducing the amount of polymeric materials deposited in landfills. The invention employs a base hydrolysis process to depolymerize, e.g. PET, which is improved by the addition of an oxidation step (preferably aeration) to oxidize impurities to highly insoluble impurities which may be removed by filtration, and may be further improved by the use of a quaternary ammonium hydroxide or a nonionic surfactant in the hydrolysis stage.

Etching liquid for polyimide and its use

Abstract: PURPOSE:To obtain a etching liquid for polyimide containing respective specific amounts of quaternary ammonium hydroxide, amino alcohol and alcohol as essential components, having high etching speed, capable of forming a through hole and a deep pattern and useful for electronic material, etc. CONSTITUTION:The etching liquid contains (A) 5-20wt.% of a quaternary ammonium hydroxide such as tetramethylammonium hydroxide, (B) 10-60wt.% of an amino alcohol such as 2-8C aliphatic or alicyclic amino alcohol (e.g. ethanolamine) and (C) 20-80wt.% of an alcohol such as 1-6C aliphatic alcohol as essential components. The etching liquid is preferably used for the wet etching of a polyimide or a fluorine-containing polyimide having low thermal expansion coefficient.

Method for prepn. of calcium borate from boride ore

Abstract: Process for preparing series calcium borate products represented by ACaOEB2O3nH2O (where A=1-5, E=1-11 and n=0-20) includes such technological steps as calcifying borate solution from ore with calcium nitrate and calcium hydroxide and regulating pH value with calcium or ammonium hydroxide Different calcium borate products may be obtained by adding different quantities of Ca(NO3)2 and Ca(OH)2 and regulating different pH values A press filter is used for solid-liquid separation to greatly reduce boron loss and the consumptions of water and steam

Vinyl surface cleanser and protectant

Abstract: A method and composition for cleaning and protecting vinyl, rubber and leather surfaces. The composition comprises a water-based emulsion of acrylic copolymer of RHOPLEX® HA-12, manufactured by Rohm and Haas of Philadelpha, Pa., polyethoxylated alkylphenol, and ammonium hydroxide. The ammonium hydroxide prevents coagulation that otherwise can result from freezing and thawing the composition. Application of the composition to aged and faded vinyl, rubber and leather surfaces cleans and restores the original luster and color without leaving an oily or glossy film.

Metal ammonium phosphate-alkylene urea buffered fertilizer.

Abstract: A method of preparing a new granular homogeneous metal ammonium phosphate-alkylene urea buffered fertilizer, containing slow releasing water insoluble nitrogen of two types which provide sustained nitrogen release. The method is based on the discovery that a strong metal ammonium phosphate matrix may be formed to homogeneously contain fine particles of alkylene urea compounds. The new buffered fertilizer provides concentrated slow release nitrogens, and phosphate, and buffering amounts of metal nutrients. The alkylene urea may be formed in-situ from liquids concommitantly with the formation of the metal ammonium phosphates, or it may be admixed as finely divided alkylene urea solids. The preferred alkylene ureas are methylene ureas and polymers, isobutylene diurea, and crotonylidene diurea. The metal nutrients are divalent and are preferably magnesium, manganese, zinc, and iron reacted as oxides, hydroxides, or carbonates. The ammonium ion is supplied in the method as anhydrous ammonia, ammonium hydroxide, and preferably as a combination of phosphoric acid and ammonium phosphate. The magnesium, ammonium, and phosphorus entities are reacted at about a mol ratio of 1.0 to 1.0 to 1.0 at about the boiling point of water, and at about atmospheric pressure to form a new fertilizer composition.

Method for recovering organic quaternary ammonium hydroxide out of waste liquid

Abstract: PURPOSE:To provide a method for recovering efficiently and inexpensively organic quaternary ammonium hydroxide of high purity as a value out of waste liquid containing at least organic quaternary ammonium hydroxide. CONSTITUTION:The method for recovering organic quaternary ammonium hydroxide out of waste liquid containing at least organic quaternary ammonium is provided. The method consists of the adsorption process for absorbing the organic quaternary ammonium ions in the waste liquid onto cation exchanger by bringing the waste liquid into contact with cation exchanger, the elution process for eluting the organic quaternary ammonium ions by bringing eluting liquid into contact with the cation exchanger to which the organic quaternary ammonium ions are absorbed, and the electrolytic process in which organic quaternary ammonium ion water solution is recovered by the electrolysis of the eluting liquid prepared in the elution process. Also at that time, anode liquid extracted out of the electrolytic process is circulated in the elution process and used as the eluting liquid.

Recovery of fluoride from waste solutions

Abstract: Fluoride is recovered from an aqueous ammonium fluoride and ammonium hydroxide solution by electrolyzing the solution in an electrochemical cell having an ion-exchange membrane between a catholyte chamber and an anolyte chamber whereby hydrofluoric acid is formed and the concentration of ammonium hydroxide is enriched. Part of the hydrofluoric acid can be combined with the ammonium fluoride remaining after the ammonium hydroxide had been stripped from the treated solution to produce ammonium acid fluoride.

Surface characterization and liquefaction of iron- and molybdenum-impregnated subbituminous coal

Abstract: Results are presented from a study of the preparation and characterization of Wyodak subbituminous coal impregnated with iron and iron-molybdenum salts by the incipient wetness (IW) technique. X-ray photoelectron spectroscopy (XPS) was used to examine the surface composition and chemistry of coals impregnated with 0.7-2.0 wt% Fe and 500-1000 ppmw Mo. Various salts were used in preparing the impregnated coals including ferric nitrate, ferric sulfate, ferrous sulfate, and ammonium molybdate. The surface concentration of Fe increased as the amount of added Fe increased, with higher concentrations being observed for the nitrateimpregnated coals. The anions of the impregnating salts were readily removed from the samples that were treated with ammonium hydroxide solution

Treating liquid for semiconductor surface

Abstract: PURPOSE:To decrease surface tension to improve wettability and to prevent foaming due to an additive by incorporating N-alkyl-2-pyrrolidone as a surfactant into a specified quaternary ammonium hydroxide soln. CONSTITUTION:The treating liquid essentially consists of quaternary ammonium hydroxide soln. expressed by formula [R1R2R3R4N] .OH which is an org. alkali soln., and contains N-alkyl-2-pyrrolidone (N-alkyl group is an alkyl group of 6-20 carbon number) as a surfactant. In formula, R1-R4 may be same or defferent and are alkyl groups or hydroxyalkyl groups of 1-3 cxarbon number. Thereby, the treating liquid used as a developer suppresses the reduction rate of the film in an unexposed area and causes no foaming even wettability is improved by addition of the surfactant. Thus, a fine pattern can be formed without defect and the dimenasional variation of the pattern is decreased.

Method of preparing an aqueous dispersion

Abstract: A process for the preparation for an aqueous dispersion of an ethylene/unsaturated carboxylic acid copolymer which comprises chemically comminuting the polymer in the presence of an aqueous alkaline solution of ammonium hydroxide or an amine or sodium hydroxide, whereby to provide the dispersed copolymer in neutralised form. The dispersion is obtained using a shear disintegrator.

Improved process for the preparation of propargyl ammonium-chloride derivatives

Abstract: The present invention relates to a process for the preparation of L-isomer of propargyl-ammonium-chloride derivatives of the general formula (I) by decomposing D-tartarate of L-isomer of the amine of the general formula (II) and by reacting the obtained L-isomer amine of the general formula (II) in the presence of a base with a halide of the general formula (V), and by reacting the so-obtained L-isomer of the general formula (III) with hydrogen-chloride in an organic solvent, wherein - x stands for a halogen atom, - y stands for a hydrogen or fluorine atom which comprises releasing the amine base from the D-tartarate of the L-isomer of the amine of the general formula (II), wherein y is as given above, in aqueous suspension with ammonium hydroxide or basic alkaline salt and/or ammonium salt, and reacting same with 1-1.5 mole equivalent of a halide of the general formula (V), wherein - x is as defined above - at 0-50 °C in a buffer system of the pH of 8-12 directly formed in the course of the base release and after separating the aqueous layer extracting the mixture containing L-isomer amines of the general formulae (II) and (III) in the organic layer with water and with a mixture of ammonium hydroxide and water and/or with a solution of aqueous phosphate salt of a pH of 5.5-7.5 and dissolving the L-isomer amine of the general formula (II) or salts thereof into the aqueous layer and selectively separating it from the L-isomer amine of the general formula (III) and converting the L-isomer amine of the general formula (III) after distillation to L-isomer salt of the general formula (I) by a method known per se.