Showing papers on "Ammonium hydroxide published in 1989"

Prevention of chain cleavage in the chemical synthesis of 2'-silylated oligoribonucleotides.

Abstract: Strong aqueous ammonium hydroxide used to remove N-acyl protecting groups from synthetic oligoribonucleotides causes removal of some alkylsilyl protecting groups from 2'-hydroxyls and leads to chain cleavage. This problem is most severe when 30% ammonium hydroxide is used and substantially reduced but still detectable when 3:1 ammonium hydroxide-ethanol is used. We have virtually eliminated this unwanted cleavage by incorporating the labile phenoxyacetyl amino protecting group on adenosine and guanosine. The N-benzoyl protecting group remains adequate for cytidine nucleosides. Synthetic oligoribonucleotides containing these N-acylated nucleosides and 2'-t-butyldimethylsilyl or 2'-triisopropylsilyl protecting groups can be deacylated by room temperature treatment in saturated anhydrous methanolic ammonia (8-12 h) without causing any detectable chain cleavage.

Preparation and characterization of glycerol-based cleavable surfactants and derived vesicles

Abstract: Four cleavable double-chain surfactants were synthesized: [2,2-diheptadecyl-1,3-dioxolan-4-yl) methyl] trimethylammonium methanesulfonate(1a), the analogous bromide(1b), [(2,2-diheptadecyl-1,3-dioxolan-4-yl) methyl] dimethyl(3-sulfopropy) ammonium hydroxide inner salt(1c), and sodium 3-[(2,2-diheptadecyl-1,3-dioxolan-4-yl) methoxyl]-1-propanesulfonate(1d). Vesicles of 1a, 1b, and 1d prepared by sonication were characterized by 1 H NMR line width narrowing, dynamic laser light scattering, differential scanning calorimetry, and dye entrapment and leakage studies

Process for the preparation of aqueous solutions of 2-hydroxy-4-methylthio-butyric acid

Abstract: A process is described comprising neutralization with ammonium hydroxide of the reaction mixture generated by the hydrolysis of 2-hydroxy-4-methylthio-butyronitrile by sulphuric acid, so as to obtain an aqueous phase and an organic phase which, once separated, are subjected to evaporation to remove the ammonium sulphate formed. For the aqueous phase, this sulphate is removed as a byproduct; and for the organic phase, it is recirculated to the neutralization vessel. The 2-hydroxy-4-methylthio-butyric acid obtained from the organic phase is subsequently diluted with water and possibly stabilized with sulphuric acid. The product obtained is useful as a food supplement in animal diets.

Process for sweetening a sour hydrocarbon fraction

Abstract: This invention relates to a process for sweetening a sour hydrocarbon fraction containing mercaptans. The process involves contacting the hydrocarbon fraction in the presence of an oxidizing agent with a catalytic composite, ammonium hydroxide and a quaternary ammonium hydroxide. There is a synergistic effect between the ammonium hydroxide and the quaternary ammonium hydroxide. Use of ammonium hydroxide instead of an alkaline hydroxide allows the waste stream to be re-used in other parts of the refinery, and allows for easier disposal of the waste stream.

High performance liquid chromatography of phospholipids with flame ionization detection

Abstract: The three major soy phospholipids were determined by normal phase high performance liquid chromatography with flame ionization detection. A Beckman Ultrasphere silica column was utilized with a solvent gradient composed of chloroform and premixed methanol/ ammonium hydroxide. This chromatographic system produced excellent resolution of the three major phospholipids and triglyceride component as well as some of the minor constituents in soy oil lecithin. Ammonium hydroxide improved peak shape and resolution but caused the peaks for the phospholipids to appear as doublets. Quantitative analysis was accomplished by the external standard method.

3-Quaternary ammonium 1-carba-1-dethiacephems

Abstract: A series of structurally unique 1-carba-1-dethiacephems is described. The structural stability of the 1-carba-1-dethiacephem nucleus was essential for the preparation of this series of 3-quaternary ammonium carbacephems. The known p-nitrobenzyl 7 beta-(phenoxyacetamido)- 3-[(trifluoromethyl)sulfonyl]oxy]-1-carba-1-dethia-3-cephem- 4-carboxylate served as both a quaternization substrate as well as a precursor to derivatives such as allyl 7 beta-[[2-[allyloxy)carbonyl]amino-4- thiazoly] (methoxyimino)acetyl]amino]-3-[(trifluoromethyl) sulfonyl] oxy]-1-carba-1-dethia-3-cephem-4-carboxylate. Quaternization of these enol triflates was accomplished either by dissolution in acetonitrile containing the base or by dissolution in the base, with or without warning to 50 degrees C. Bases nucleophilic enough to displace the triflate include a variety of substituted pyridines and N-methylimidazole. Deprotection then produced a very active series of 1-[7 beta-[(2-amino- 4-thiazolyl)(methoxyimino)acetyl]amino]-2-carboxy-8-oxo- 1-azabicyclo[4.2.0]oct-2-en-3-yl] quaternary ammonium hydroxide inner salts. These compounds were extremely potent antibacterials against a broad range of Gram-positive and -negative bacteria including constitutive cephalosporinase producers, such as Enterobacter cloacae. The compounds exhibit similar hydrolysis kinetics and pharmacokinetics to the analogous cephalosporin-3'-quaternary ammonium salts.

Method for purifying quaternary ammonium hydroxides

Abstract: A process is described for reducing the latent halide content of a solution of quaternary ammonium hydroxide containing latent halide which comprises the steps of (A) providing an electrolytic cell comprising an anode and a cathode, (B) charging a solution containing at least one quaternary ammonium hydroxide which contains latent halide into said electrolytic cell, (C) passing a current through the electrolytic cell to lower the latent halide content in the solution, and (D) recovering the quaternary ammonium hydroxide solution from the electrolytic cell. A process also is described for reducing the latent and ionic halide content of quaternary ammonium hydroxides prepared from the corresponding halide.

Apparatus for generation of hydrogen and other gases from the decomposition of organic matter

Abstract: An apparatus and method are disclosed for electrolysis of organic cellulose material to produce free hydrogen Ground vegetation is saturated with liquid ammonium hydroxide to produce a mixture The mixture is preferably fed through a tubular device using a screw feed mechanism or other appropriate feed mechanism, past cathodes and anodes which are positioned at intervals and in opposition in walls of the tubular device Electrolysis is conducted on the mash and free hydrogen is collected at the cathodes via a tube connection adjacent to each cathode Oxygen is also produced and collected The hydrogen may be purified by utilizing a hydrogen scrubber which uses liquid nitrogen to condense and remove any contaminating gases The collected hydrogen may be reacted with nitrogen and oxygen to replenish the ammonia for input to the process It may also be reacted with oxygen to produce water, or it may be used for other purposes such as for fuel

Production of quaternary ammonium hydroxide

Abstract: PURPOSE:To produce the title high-purity quaternary ammonium hydroxide by forming an electrolytic cell with many chambers, supplying quaternary ammonium hydroxide to a cathode chamber and an intermediate chamber on the cathode side, supplying an aq acidic soln to an anode chamber and the intermediate chamber on the anode side, and carrying out DC electrolysis CONSTITUTION:Two or more cation-exchange membranes are arranged on the cathode side, an anion-exchange membrane is arranged on the anode side, and a cation- exchange membrane is arranged between the anode and the anode-exchange membrane to form the multiple-chamber electrolytic cell Quaternary ammonium hydroxide is supplied to the intermediate chamber separated by the cathode chamber and the two cation-exchange membranes A quaternary ammonium salt is supplied to the intermediate chamber separated by the cation-exchange membrane on the cathode side and the anion-exchange membrane, and an aq acidic soln is supplied to the intermediate chamber separated by the cation-exchange membrane on the anode side and the anode- exchange membrane and to the anode chamber A DC current is supplied to the anode and the cathode chamber to cause electrolysis, and high-purity quaternary ammonium hydroxide is formed As a result, the service life of the anion-exchange membrane is prolonged, and the deterioration of the anode can be prevented

Formation of tabular silver halide emulsions utilizing high pH digestion

Abstract: The invention is generally accomplished by providing a tabular silver halide emulsion formation process in which the pH is controlled to greater than 9 by the addition of an alkali base prior to digesting to form uniform nucleated silver bromide particles. In a particularly preferred process the emulsion is adjusted to a pH greater than 9 by the use of sodium hydroxide, digestion takes place in between 3 and 7 minutes, and the emulsion making is completed in less than 100 minutes without the use of ammonium hydroxide. The emulsions formed are suitable for x-ray films and produce the image tone required by radiologists.

Method of making high purity dense silica of large particle size

Abstract: A method of making high purity, dense silica of large particles size is described. Tetraethylorthosilicate is mixed with ethanol and is added to a dilute acid solution having a pH of about 2.25. The resulting solution is digested for about 5 hours, then 2N ammonium hydroxide is added to form a gel at a pH of 8.5. The gel is screened through an 18-20 mesh screen, vacuum baked, calcined in an oxygen atmosphere and finally heated to about 1200° C. in air to form a large particle size, high purity, dense silica.

Characterization of co-precipitated Al2O3-SiO2 gels

Abstract: Aluminum nitrate and tetraethyl orthoxysilane were used as starting materials. They were mixed at different ratios ranging from 1.8 to 4.8 (Al3+/Si4+) and dissolved in ethyl alcohol. The pH of the reaction solution was also varied by the addition of ammonium hydroxide at a range of 8.3 to 10.4. Experiments were carried out at 25 and 60°C. In each case the materials were hydrolysed to a colloidal solution which was then filtrated and the resulting colloids retained on the filter as a gel which after drying at 110°C became a xerogel. The xerogels then were characterized by BET, SEM/TEM, and XRD/XRF.

Chlorination process for recovering gold values from gold alloys

Abstract: A process for the recovery of precious metal values as essentially pure gold from gold alloys in the form of thin strips 0.05 to 0.25 inch thick having a gold content of up to 80% gold comprising chlorinating the strips at a temperature of 300 to 700 degrees Centigrade to form a metallic gold/metal chloride mixture and removing the metal chlorides from the gold in the mixture using an aqueous wash. When silver is part of the alloying metal, essentially pure silver is recovered by first washing the metallic gold/metal chloride mixture with hydrochloric acid and then with ammonium hydroxide and recovering the silver from the ammonium hydroxide.

Method of making europium activated yttrium oxide phosphor

Abstract: A europium activated yttrium oxide phosphor is prepared as follows. Europium oxide is dissolved in nitric acid. Ammonium hydroxide is added to precipitate europium hydroxide, which is then dissolved in citric acid monohydrate to form europium citrate solution. Yttrium oxide powder is added to the solution to form a slurry, which is then spray dried. The spray dried powder is fired at a high temperature to form the phosphor.

Production of platinum powder

Abstract: PURPOSE: To produce spherical platinum powder of uniform particle size by adding an ammonium compd. to an aq. soln. or suspension of a platinum compd. and using a hydrazine compd. as a reducing agent. CONSTITUTION: An ammonium compd. such as ammonium hydroxide, ammonium acetate, ammonium carbonate, ammonium borate, ammonium chloride or ammonium tartrate is added to an aq. soln. or suspension of a platinum compd. such as chloroplatinic acid, ammonium chloroplatinate or potassium chloroplatinate. A hydrazine compd. such as hydrazine hydrate, hydrazine hydrochloride or hydrazine sulfate as a reducing agent is then added to the soln. or suspension to deposit fine platinum particles whose particle size can be controlled to the range of 0.5-8.0μm. COPYRIGHT: (C)1990,JPO&Japio

Developing agent composition for photosensitive planographic plate improved in deterioration of visible image

Abstract: PURPOSE:To prevent the deterioration of a visible image by incorporating N- phenyl diethanol amine or N-phenyl ethanol amine, an anionic surfactant and 0001-1wt% of a dyestuff in the developing agent composition CONSTITUTION:Each of N-phenyl diethanol amine or N-phenyl ethanol amine or both of them are incorporated in the developing agent composition, and the compounding amount of the amine is preferably 001-10wt%, more preferably 05-5wt% based on the developing composition An alkali agent is preferably incorporated in the developing agent composition The alkali agent is exemplified by an org alkali agent such as triethanol amine or tetraalkyl ammonium hydroxide or an ammonium org silicate, etc The compounding amount of the alkali agent is preferably 005-20wt%, more preferably 01-10wt% Thus, the deterioration of the visible image can be prevented

Continuous process for purifying molybdenum

Abstract: A process for purifying molybdenum, which comprises first leaching impure molybdenum trioxide containing potassium in a liquid medium of nitric acid, and an ammoniacal liquor, wherein the nitric acid concentration is about 3.5 to 4.0 moles per liter and the ammonium nitrate concentration is about 0.5 to 1.0 moles per liter, at greater than 50° C. to solubilize the major portion of the potassium and produce a once-leached molybdenum trioxide and a first liquor, removing the once-leached molybdenum oxide from the first liquor, re-leaching the once-leached molybdenum trioxide in nitric acid having a concentration of about 3.5 to 4.0 moles per liter, at greater than 50° C. to produce a twice-leached molybdenum trioxide and a second liquor, removing the twice-leached molybdenum oxide from the second liquor, water washing the twice-leached molybdenum trioxide, digesting the molybdenum trioxide in ammonium hydroxide at greater than 50° C. at a pH of greater than 9.0 to form an ammonium molybdate solution, crystallizing ammonium dimolybdate from the ammonium molybdate solution, separating the ammonium dimolybdate crystals from the spent mother liquor which contains the balance of the starting molybdenum, combining a sufficient amount of spent mother liquor with a sufficient amount of the second liquor to provide the ammonium ion required to maintain the concentration of ammonium nitrate and nitric acid in the liquid medium, and using the combined liquors as the liquid medium in the first leaching step.

Sterilization control apparatus

Abstract: PURPOSE:To supply sterilized water almost containing no free chlorine, by injecting ammonia and chlorine in the raw water of a water treatment plant to generate combined chlorine and controlling the injection rate of ammonia and chlorine. CONSTITUTION:The chlorine demand quantity and intake flow amount 5 of raw water are measured and the concn. of ammonia is measured by an ammonia meter 10. The raw water flowing in a water arrival basin 1 is guided to a quick mixing basin 2 and ammonium hydroxide is injected in the raw water on the way to be mixed with the raw water. Next, this raw water is guided to the quick mixing basin 2 to inject chlorine and a flocculant in said raw water. Chlorine is used in the sterilization of bacteria or the oxidation of a metal ion and the flocculant flocculates the turbid substance in the raw water into flocs which are, in turn, sedimented and removed in a sedimentation basin 3. The supernatant water becoming clear in the sedimentation basin 3 is guided to a water distribution basin 4 to be stored therein and, on the outlet side of the water distribution basin 4, residual chlorine is measured by a total residual chlorine meter 14 and a free residual chlorine meter 15 to distribute water to a user.

Purification of aqueous solution of quaternary ammonium hydroxide

Abstract: PURPOSE: To obtain the subject compound useful as an organic alkali agent in high purity by electrolyzing an aqueous solution of a quaternary ammonium salt and contacting the resultant aqueous solution of a quaternary ammonium hydroxide with a specific ion exchange resin. CONSTITUTION: An aqueous solution of a quaternary ammonium hydroxide produced by the electrolysis of an aqueous solution of a quaternary ammonium salt in a diaphragm cell is treated with a polystyrenesulfonic acid-type ion- exchange resin having a divinylbenzene content of ≥10wt.% and high crosslinking degree. Trace metal ions existing in the aqueous solution containing the quaternary ammonium hydroxide of formula (R 1 , R 2 , R 3 and R 4 are same or different alkyl, alkynyl, benzyl or hydroxyalkyl) can be selectively removed by this process to obtain the objective compound having high purity. COPYRIGHT: (C)1991,JPO&Japio

Developing solution for positive type resist

Abstract: PURPOSE: To stably form a resist pattern high in contrast by adding an alkali- soluble cyclic nitrogen compound in an aqueous organic alkaline solution. CONSTITUTION: It is preferred to use as the aqueous organic alkaline solution the one containing tetramethyl ammonium hydroxide or/and choline in a concentration of, usually, 1.0 - 10wt.%, preferably, 1.5 - 7.5wt.%, and the alkali-soluble cyclic nitrogen compound is added to the solution in an amount of, usually, 0.1 - 10wt.%, preferably, 0.3 - 5.0wt.% of the solution, thus permitting contrast to be enhanced, accordingly, a resist pattern extremely good in the sectional form to be formed. COPYRIGHT: (C)1990,JPO&Japio

Semiconductor treating agent

Abstract: PURPOSE:To enhance detergency and to make etching action very low, by including specified quarternary ammonium hydroxide, nonionic surface active agent and hydrazine at a specified ratio CONSTITUTION:Qurternary ammonium hydroxide is a compound, which is expressed by a general formula I As an example, trimethyl-2- hydroxyethylammonium hydroxide or the like is shown, and it is used within a concentration range of 001-30wt% in a total solution As nonionic surface active agent, polyoxyethylene alkyl ether type nonionic surface active agent, which is expressed by a general formula R-O(CH2CH2O)nH(where R is C8-C18; and (n) is 8-15), or the like is suitably used It is used within a concentration range of 0001-5 wt% is the total solution The hydrazine is used within a concentration range of 001-30 wt% in the total solution

Preparation of methyl 3-aminocrotonate

Abstract: PURPOSE: To industrially advantageously prepare the subject compd. being useful as a starting compd. for a remedy for cardiovascular diseases by reacting methyl acetoacetate with ammonia in the presence of water in a specified temp. range. CONSTITUTION: Methyl acetoacetate is reacted with ammonia (1.5-4.0 mol ammonia to 1 mol methyl acetoacetate is pref.) in the presence of water (0.05-3.0 mol water to 1 mol methyl acetoacetate is pref.) in a temp. range of 35-70°C to obtain methyl 3-aminocrotonate. In addition, if necessary, when ammonium hydroxide is added, the reaction is pref. performed at 40-45°C. In addition, the reaction may be performed by saturating a mixture of methyl acetoacetate and water with ammonia gas at 55-65°C. By-products are little and the reaction is rapidly advanced and utilization efficiency of a manufacturing apparatus is high. In addition, there exists no need for using a solvent in the reaction. COPYRIGHT: (C)1990,JPO

Acrylic resin composition

Abstract: PURPOSE:To obtain the title composition which is lowly viscous, has high crosslinkability and can give a flexible and tough high-elasticity paint film, by polymerizing a specified compound and an alpha,beta-ethylenically unsaturated monomer CONSTITUTION:A specified amount of tetrahydrophthalic acid is added dropwise to a solution containing both of (meth)acryloyl halide and a Lewis acid metal salt and the mixture is heated with agitation to effect polymerization through ring opening The polymerization is stopped by adding water, an alkaline solution or a quat ammonium hydroxide (eg, tetramethylammonium hydroxide) to obtain a compound of formula I (wherein R is H or methyl, and n is 3-100) 20-100mol% this compound and 80-0mol% another alpha,beta-ethylenically unsaturated monomer are polymerized to obtain an acrylic resin composition of a number- average MW of 1,000-100,000, having a soft-structure oxytetramethylene chain of formula II in the skeleton of the resin and a reactive hydroxyl group at the terminal of a side chain

Cleaning fluid for silicon layer

Abstract: PURPOSE:To obtain a cleaning fluid wherein th etching rate of SiO2 is decreased as compared with Si, and disadvantage does not develop even in the case of cleaning of a silicon layer in which an SiO2 layer partially exists, by composing the cleaning fluid of ammonium hydroxide, aqueous hydrogen peroxide, water and a water-soluble aluminum compound. CONSTITUTION:The title fluid is composed of a mixed solution of ammonium hydroxide, aqueous hydrogen peroxide, water and water-soluble aluminum compound. For the water-soluble aluminum compound, the following are used; aluminum trichloride, aluminum nitrate, aluminum sulfate and aluminum hydroxide. The content of aluminum ion in the above mixed solution is 0.02-20ppm. By this composition, the etching rate for silicon dioxide can be made about equal to or less than 1.5Angstrom /min, as compared with that of silicon which is about 7.5Angstrom /mim. Therefore the etching quantity of the silicon dioxide layer is restrained in a small range, and foreign matter mainly composed of silicon particle can be washed and eliminated.

Cleaning method for semiconductor substrate

Abstract: PURPOSE:To prevent fine particles from adhering onto a semiconductor substrate by introducing ammonia into pure water as alkaline solution, dipping the substrate while introducing ozone to the aqueous solution, and cleaning it. CONSTITUTION:Pure water heated to a predetermined temperature (e.g., 60 deg.C) is supplied to a treating tank 1. After the pure water is supplied, gas, such as ammonia is supplied from a gas supply unit to the tank 1. The supplied ammonia gas is partly absorbed to the pure water, becoming ammonium hydroxide and hence alkaline cleaning solution 5. A semiconductor substrate 10 is dipped in the solution 5. Simultaneously, ozone is supplied by an ozone supply unit 3. The substrate 10 is cleaned in this state for a predetermined period of time, and rinsed with pure water. Thus, it can prevent fine particles form adhering onto the substrate 10.