Showing papers on "Potassium hydroxide published in 1996"

Biochar as a precursor of activated carbon.

Abstract: Biochar was evaluated as a precursor of activated carbon. This product was produced by chemical activation using potassium hydroxide. The effects of operating conditions of activation process, such as temperature, activating agent to biochar mass ratio, and nitrogen flow rate, on the textural and chemical properties of the product were investigated. Activated carbon produced by this method has internal surface area at least 50 times than that of the precursor and is highly microporous, which is also confirmed by scanning electron microscopy analysis. Fourier-transform infrared spectroscopy analysis showed development of aromatization in the structure of activated carbon. X-ray diffraction data indicated the formation of small, two-dimensional graphite-like structure at high temperatures. Thermogravimetric study showed that when potassium hydroxide to biochar mass ratio was more than one, the weight loss decreased.

Method of treating lithium manganese oxide spinel

Abstract: A method of treating lithium manganese oxide of spinel structure is disclosed. The method involves heating the lithium manganese oxide spinel in an atmosphere of an inert gas which does not react with the spinel. Such gases may be selected advantageously from argon, helium, nitrogen, and carbon dioxide. Preferred nonreacting gases which may be employed for spinel treatment are nitrogen or carbon dioxide. The spinel is advantageously treated with such gases at elevated temperatures. Alternatively, the spinel may be first coated with a hydroxide, preferably lithium, sodium or potassium hydroxide and then heated in an atmosphere of carbon dioxide gas at elevated temperatures. Such treatment of lithium manganese oxide spinel has been determined to improve the performance of the spinel when employed as an electrode in rechargeable cells such as lithium-ion cells.

Method for manufacture of products containing disalts of formic acid

Abstract: The present invention relates to a method for manufacture of products containing disalts of formic acid. Potassium hydroxide, carbonate, bicarbonate or formate, sodium hydroxide, carbonate, bicarbonate or formate, cesium hydroxide, carbonate, bicarbonate or formate or ammonium formate or ammonia is mixed with formic acid at 40-100 °C, the mixture is cooled and centrifuged. The filtrate containing acid salt is collected. The filter cake is transported to a drier/mixer where other disalts, calcium formate and/or a desiccant can be added.

Nickel catalysts for internal reforming in molten carbonate fuel cells

Abstract: Natural gas may be used instead of hydrogen as fuel for the molten carbonate fuel cell (MCFC) by steam reforming the natural gas inside the MCFC, using a nickel catalyst (internal reforming). The severe conditions inside the MCFC, however, require that the catalyst has a very high stability. In order to find suitable types of nickel catalysts and to obtain more knowledge about the deactivation mechanism(s) occurring during internal reforming, a series of nickel catalysts was prepared and subjected to stability tests at 973 K in an atmosphere containing steam and lithium and potassium hydroxide vapours. All the catalysts prepared showed a significant growth of the nickel crystallites during the test, especially one based on ?-Al2O3 and a coprecipitated Ni/Al2O3 sample having a very high nickel content. However, this growth of nickel crystallites only partially explained the very strong deactivation observed in most cases. Only a coprecipitated nickel/alumina catalyst with high alumina content and a deposition-precipitation catalyst showed satisfactory residual activities. Addition of magnesium or lanthanum oxide to a coprecipitated nickel/alumina catalyst decreased the stability. Adsorption and retention of the alkali was the most important factor determining the stability of a catalyst in an atmosphere containing alkali hydroxides. This is because the catalyst bed may remain active if a small part of the catalyst bed retains all the alkali.

Protective coatings in harsh environments

Abstract: The chemical stability of different coatings for micromechanical sensors is investigated. The coatings included are standard passivation layers in the IC industry: silicon oxide, silicon nitride and silicon carbide. The corrosion rates of these materials are tested in water based media with varying pH values and temperatures. Homogenous corrosion is observed yielding etch rates up to for silicon oxide, for silicon nitride and for silicon carbide at in potassium hydroxide.

XPS and SIMS Investigation of Covalently Bound Lipid on the Wool Fibre Surface

Abstract: Alcoholic alkali solutions, such as potassium t-butoxide in t-butanol and potassium hydroxide in ethanol, have been known to remove the covalently bound lipid from the wool fibre surface. In this study, x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) have been used to investigate the surface characteristics of unprocessed wool fibres (both base section and weathered tips), wool fabric and the relative effects of potassium t-butoxide and potassium hydroxide treatments. Results comparing the fibre base and tip confirm that the weathering may result in partial loss of the covalently bound lipid from the tip. In addition, a loss of sulphur has been observed. While the extent of sulphur oxidation on the surface of the base section is insignificant, the tip section may have up to 30% oxidized sulphur. There is no apparent difference between the fibres and the fabric used in this study regarding the levels of carbon, sulphur and oxidation. Potassium t-butoxide is found to be less effective than potassium hydroxide in removing the surface bound lipid. An explanation is given which supports a hypothesis that the bound lipid is located not only at the outer most surface, but that it is also trapped within the underlying protein layer. The potassium t-butoxide, due to its bulky molecular structure, may not have easy access to the trapped lipid. While the extent of oxidation of surface sulphur after potassium t-butoxide treatment is higher compared to that after potassium hydroxide treatment, the levels of sulphur loss caused by these two reagents are similar. The removal of bound surface lipid for fabric is more effective than for fibres. It is suggested that fine-scale damage to the fibre, which has been observed to occur during physical processing, is responsible for this difference.

Process for etching semiconductors using a hydrazine and metal hydroxide-containing etching solution

Abstract: An etching process for a silicon semiconductor substrate to produce a semiconductor pressure sensor or a semiconductor acceleration sensor. The etching process comprises the following steps: (a) carrying out an etching of the semiconductor without application of a voltage to the semiconductor so as to accomplish a pre-etching step, the pre-etching step including dipping the semiconductor in hydrazine hydrate; and (b) carrying out an electrochemical etching of the semiconductor by applying pre-etching step so as to accomplish a final etching step, the final etching step including dipping the semiconductor in an alkali system etching solution containing at least hydrazine (N2 H4), potassium hydroxide (KOH), and water (H2 O), the alkali system etching solution containing potassium hydroxide in an amount of not less than 0.3% by weight.

Activated charcoal for organic solvent-based electric double layer capacitor

Abstract: PROBLEM TO BE SOLVED: To increase electric double layer capacity by clarifying the elements governing static density of activated charcoal by baking vinyl chloride-based resin and then activating alkali. SOLUTION: At first, vinyl chloride-based resin is baked and carbonized, and it is desired to give a temperature of more than 2000°C for the baking which is higher than the first stage weight decrease start temperature by heat analysis. This carbonized matter is activated with alkali and activated charcoal for electrode can be created but potassium hydroxide is best suited as an activating agent to be used for alkali activation. Also, activating temperature of 500 to 1000°C and activating time of 1 to 20 hours are desired. The activated charcoal thus obtained is able to improve the weight static density of electrode when used in a capacitor if the mode of pore distribution is located between 10 and 20 angstrom. COPYRIGHT: (C)1997,JPO

Paired electrooxidation Part III: Production ofn-butyric acid fromn-butanol

Abstract: It is well known that, except for methanol and benzyl alcohol, alcohol oxidation is not easy in the absence of a redox mediator since direct oxidation of alcohols at platinum and carbon anodes is limited because of the requirement of high oxidation potentials. In earlier work, nickel in aqueous potassium hydroxide was used as the anode to cause the oxidation of primary alcohol to form carboxylic acid in current yields in excess of 90% [1]. Nickel oxide hydroxide NiO(OH), is continuously produced by the electrooxidation of nickel hydroxide. The application of NiO(OH), prepared by chemical methods, to alcohol oxidation has been well studied [2-4]. Recently, a nickel hydroxide electrode was used for alcohol oxidation through indirect electrochemical oxidation [1, 5-10]. Many papers have reported that the oxidation of alcohol has both high current efficiency and yield using a nickel or nickel hydroxide plated electrode as anode. However, when oxidation takes place in such a system, the current at the cathode does not contribute to the electrolysis process. Therefore, paired electrolysis is examined in this study with a view to increasing the total current efficiency. In paired electrolysis, hydrogen peroxide is produced at the cathode to oxidize the reactant, here n-butanol. Thus, oxidation occurs at both anode and cathode. Several papers have reported the idea of paired electrolysis [11, 12]. In these papers, oxidation did not occur by direct electrooxidation at the cathode but required indirect oxidation through redox mediators, such as, Mn3+/ 3+ 2+ 2 2 Mn 2+, V5+/V 4+, Ce /Ce ,8208-/SO4-. These redox mediators are expensive and require separation from the electrolyte. Some authors have carried out cathodic reduction of oxygen to produce hydrogen peroxide [13-16]. Some papers have reported using H202 combined with metallic redox mediators for cathodic oxidation [17, 18]. But paired electrolysis by simultaneous oxidation through peroxide compounds generated both at anode and cathode has not been reported. In this study, the combination of anodic and direct cathodic oxidation without redox mediators was carried out and paired electrolysis was examined at different controlled current values in divided and undivided cells. Though n-butanol cannot be easily oxidized, very high current efficiency was obtained. The reactions in the paired electrochemical oxidation of n-butanol to n-butyric acid may be expressed as follows. Anodic reaction [8-10]:

Sulfur-containing epoxy compound and sulfur-containing epoxy resin

Abstract: PROBLEM TO BE SOLVED: To obtain the subject new compound useful as a raw material for synthetic resins and plastic lens and a raw material for medicines, agrochemicals, epoxy resin coating materials, adhesives, semiconductor sealing agents, etc., and capable of providing a resin having a high refractive index, low disperse and impact resistance. SOLUTION: This compound is represented by formula I. The compound of formula I is obtained by reacting 1,2-bis[(2-mercaptoethyl)thio]-3- mercaptopropane with a compound represented by formula II (X is Br or Cl) in an organic solvent which is inert to both compounds (preferably benzene, toluene, xylene, methanol, ethanol, etc.) or water or a mixed solvent of the organic solvent with water in the presence of an inorganic base (preferably sodium hydroxide or potassium hydroxide), preferably at 0-25°C, under ordinary pressure for 10-100hr. COPYRIGHT: (C)1998,JPO

Formation of iron oxides by the oxidation of iron in Fe-MOH-H2O and Fe-MOH-H2O-O2 systems (M = Li, Na, K)

Abstract: The oxidation behaviours of iron powders, ca. 100 μm in diameter, in 5–50 m NaOH, 5–40 m KOH and 5–40 m LiOH solutions at 373–573 K were investigated in the absence and presence of oxygen, where m is molality. The oxidation of iron proceeded noticeably above 423 K to form Fe3O4, α-Fe2O3, α-NaFeO2, γ-Fe2O3, LixFe3−xO4 and α-LiFeO2 depending on the reaction conditions. The rate of oxidation in LiOH solutions was much slowerthan those in NaOH and KOH solutions.

Thickened scouring cleanser containing inorganic abrasives and hypochlorite bleach

Abstract: A thickened stable hard surface cleaner comprising by weight (a) from about 10 to about 30 % abrasive particles, (b) from about 0.5 to about 2.5 % of a chlorine-containing bleach, (c) from about 0.5 to about 3 % of a thickening system comprising a cross-linked polyacrylate resin having a molecular weight in the range of 1,000,000 to 10,000,000 and a synthetic smectite clay resembling natural clays of the hectorite class, the amount of said clay being from about 20 to about 80 %, preferably from 50 to 80 %, of the thickening system, (d) from about 0.25 to about 2.0 % of a bleach stable surfactant system comprising mainly anionic surfactants, (e) from 0 to about 3 % of an electrolyte selected from the group comprising sodium or potassium carbonates or silicates, and (f) sufficient amount of sodium or potassium hydroxide to attain a pH in the range of 11.5 to 13.5.

Polyurethane-based thickeners for aqueous compositions

Abstract: The present invention relates to a process for the preparation of polyurethanes suitable for use as thickeners for aqueous compositions by reacting at an NCO/OH equivalent ratio of 0.9:1 to 1.2:1 a) a polyether component having an OH number of 10 to 30 mg KOH/g and obtained by the alkoxylation of a mixture of a1) 30 to 80 mole % of a monofunctional alcohol or alkylphenol having 8 to 30 carbon atoms, a2) 2 to 10 mole % of sodium hydroxide or potassium hydroxide, a3) 10 to 60 mole % of water and a4) 0 to 10 mole % of a trihydric to hexahydric alcohol having a molecular weight of 92 to 600, with ethylene oxide or a mixture of ethylene oxide with up to 20 mole %, based on the total moles of alkylene oxides, of propylene oxide, in which the percentages of a1) to a4) add up to 100, with b) a polyisocyanate component containing at least one organic diisocyanate, optionally in admixture with up to 20 mole %, based on the total moles of component b), of higher than difunctional polyisocyanates. The invention also relates to the polyurethanes obtainable by this method and their use, optionally in combination with other thickeners, for the thickening of aqueous systems.

Pre-treatment of metallic base material surface

Abstract: PROBLEM TO BE SOLVED: To provide a pre-treating method for easily wetting the surface of a metallic base material by a remarkably simple operation that the metallic base material is brought into contact with an aq. solution, containing an alkali compound or hydrogen peroxide, or a hot water or steam. SOLUTION: The metallic base material is dipped into the aq. solution containing 10mol/l alkali compound such as sodium hydroxide, potassium hydroxide or hydrogen peroxide, for example, for 3hr in the boiling state and by the pre-treatment, the contact angle particularly of an aq. solution or the like to the surface of the metallic base material is lowered to improve the wettability. A coating film composed of a calcium phosphate based sintered compact is formed on the surface of the metallic base material by applying an aq. solution containing calcium phosphate, heat treating and sintering. Particularly if the metallic base material is used for a in-vivo hard tissue substitutive member, the in-vivo hard tissue substitutive member having excellent strength and bioactivity is obtained. COPYRIGHT: (C)1997,JPO

Process for the manufacture of pure lead oxide from exhausted batteries

Abstract: The present invention relates to an improved process for producing lead oxide in a pure state from a spent paste resulting from exhausted acid batteries. The spent paste is first calcined and desulfurized, then leached by a concentrated solution comprising an alkali hydroxide at a temperature above 100° C. The separated solution is contacted with a ketone resulting in a suspension from which the α-lead oxide constituent is recovered. The solutions of alkali and ketone are recycled in the process. The preferred alkali constituents are selected from sodium hydroxide or potassium hydroxide, preferably containing also a small amount of sulfate of the respective alkali metal of the hydroxide used.

Aqueous suspensions of poly(ethylene oxide) useful as a flocculent

Abstract: A method is provided for using an aqueous suspension of at least 15% of poly(ethylene oxide)(PEO) as a flocculent. PEO is dispersed in an aqueous solution of at least one salt selected from the group consisting of sodium or potassium formate, sodium or potassium hydroxide, sodium or potassium citrate, sodium or potassium acetate, sodium chloride or mixtures thereof to form a poly(ethylene oxide) suspension having at least 15% of poly(ethylene oxide) by total weigh. This suspension is dissolved in an aqueous system; and said dissolved aqueous system is added in conjunction with a solution of a coagulant or synthetic flocculents selected from the group consisting of alum, polyaluminum chloride, sodium aluminates, polyamines, polyacrylamides, copolymers of acrylamide with cationic or anionic monomers, or polyethylene imine, to an aqueous slurry containing finely divided materials, whereby said dissolved aqueous dispersion enhances the separation of the finely divided materials from the liquid in the aqueous slurry.

Process for recovering metallic lead from exhausted batteries

Abstract: The present invention relates to a process for the recovery of metallic lead from exhausted lead-acid batteries. According to the invention, the metallic scrap obtained thereof is treated by a smelting operation which is carried out under a layer of a molten flux. The flux comprises alkali hydroxide and optionally also carbonate(s) and sulfate(s) of said alkali. The temperature which is maintained during the smelting is between 350° C. to 600° C. and most preferably in the range of between 450° C. to 550° C. The preferred weight ratio between the metallic scrap and the flux is between 15 to 45. Generally, the alkali flux is selected from sodium hydroxide and potassium hydroxide and mixtures thereof. The process is characterized by a very extent of lead recovery compared with the known processes and absence of exhausted gases.