Potassium hydroxide properties, chemical

V,lV-Dimethylformamide is a widely used solvent for many recently developed synthetic procedures because of its powerful solvating properties and its chemical stability in the absence of acidic or basic catalysts. However, distillation at atmospheric pressure (b.p. 149-156 °C) or contact with desiccants such as solid sodium or potassium hydroxide or calcium hydride causes varying degrees of decomposition. 

A unique active carbon having very high surface areas over 2500 m / gm, and extraordinary adsorptive capacities was developed in our laboratories. (1) This paper will describe its development, manufacture, properties, and uses. Until recently, samples of this carbon, which were provided worldwide for research and evaluation, were identified as Amoco Grades PX-21, 22, 23, and 24 in the powdered form and Amoco GX-31 and 32 in granular form. The carbon is made (Figure 1) by a direct chemical activation route in which petroleum coke or other carbonaceous sources are reacted with excess potassium hydroxide, KOH, at 400° to 500°C to an intermediate product that is subsequently pyrolyzed at 800°-900°C to active carbon and potassium salts. The salts are removed by water washing. 

An exceptional active carbon has been developed with a high effective surface area and high adsorptive capacity. It is prepared by a controlled chemical activation route using potassium hydroxide and a carbonaceous source, usually petroleum coke, to give a consistent quality product. It has been tested in a gamut of conventional and new uses with performance ratios averaging 2 to 4 times better than other grades of active carbon. Because of its unique structure and properties, it is likely that many new uses will be developed as it now becomes commercially available. 

The swelling of cotton with an aqueous solution of sodium hydroxide is an important com mercial treatment. It is called mercerization after its discoverer, John Mercer, who took a patent on the process in 1850 [308]. Other alkali metal hydroxides, notably lithium hydroxide and potassium hydroxide, will also mercerize cotton, but normally sodium hydroxide is used. Mercerization is utilized to improve such properties as dye affinity, chemical reactivity, dimensional stability, tensile strength, luster, and smoothness of the cotton fabrics [309]. The treatment is normally applied either to yarn or to the fabric itself either in the slack state to obtain, for example, stretch products, or under tension to improve such properties as strength and luster. The interaction of alkali metal hydroxides and cellulose has been extensively reviewed. Earlier reviews can be traced from relatively recent ones [99,310,311]. 

Activated carbon modified chemically with potassium hydroxide via low temperature wet impregnation method for NOx adsorption was used. The present study examined adsorption and desorption behaviors and the accompanied surface chemistry. In particular, typical desorption behavior was examined after NOx was adsorbed at 100°C while the temperature was increased up to 600°C. This study found that the presence of a relatively larger amount of adsorbent delays surface oxidation. NOx has become oxidized while inducing three types of physical and chemical bonds on the surface of BHAC. The results concerning the surface properties after adsorption and desorption were analyzed using various instruments. Potassium existed on the surface without consumption as K-IAC was adsorbed by potassium oxide after desorption. 

For isolation of hardwood xylans by way of holocellulose, a choice has to be made between the different methods available, according to the objectives to be attained. If molecular properties are to be investigated, the modified chlorine-2-aminoethanol method and, possibly, also the method of Klauditz are suitable. For chemical studies, especially if the location of the 0-acetyl groups is to be established, only chlorine dioxide or chlorous acid can be used. The subsequent extraction of the holocellulose will also have to be adapted to the desired ends. For isolation of a pure (4-0-methylglucurono)xylan, aqueous potassium hydroxide is excellent, since it gives almost quantitative yields and seldom causes removal of the gluco-mannan. If necessary, further purification can be effected by precipitation with Fehling solution. - ... 

CHEMICAL PROPERTIES reacts violently with potassium hydroxide FP (215°F)... 

CHEMICAL PROPERTIES stable under ordinary conditions of use and storage hydrolyzes slowly in water to telluric acid (H606Te) more quickly hydrolyzed by aqueous potassium hydroxide when pure, does not attack glass corrosive to mercury not as chemically inert as sulfur hexafluoride (SF(,) and selenium hexafluoride (SeFs) because the maximum covalence of tellurium is greater than six FP (NA) LFLZUFL(NA) AT(NA) HC(NA) HF(-1318.0 kJ/mol gas at 25 C) Tc (83 C, 181.4 ). 

CHEMICAL PROPERTIES most zirconium compounds are considered inert zirconium metal can react with hydrofluoric acid, aqua regia, and hot phosphoric acid attacked hy fused potassium hydroxide or potassium nitrate not attacked by cold, concentrated sulfuric or hydrochloric acid resistant to attack by nitric acid very resistant to corrosion oxidizes rapidly at 6°C nitrided slowly at 700°C compact form combines with oxygen, nitrogen, carbon, and the halogens on prolonged heating FP (NA) LFLAJFL (NA) AT (NA) HF (0.0 kJ/mol crystal at 25 C) Hf (21.0 kJ/mol at 2127.85K). 

Diphenylcarbinol (benzhydrol), (C6H5)2CHOH, is an example of a secondary aromatic alcohol. It resembles in chemical properties the analogous aliphatic alcohols, but the presence of the two aryl radicals brings about an activity which is not observed among the derivatives of the paraffins. Diphenylcarbinol is made most conveniently by reducing benzophenone with zinc and an alcoholic solution of potassium hydroxide —... 

The chemical properties of the three isomers illustrate the effect of the relative position of substituents on their activity. o-Nitrobromobenzene (m.p. 43°) is converted into o-nitroaniline when heated at 190° with an alcoholic solution of ammonia, and into o-bromophenol when heated at a high temperature with water and potassium hydroxide. In one reaction the halogen atom is removed by ammonia, and in the other the nitro group by potassium hydroxide. p-Nitrobromobenzene enters into similar reactions, but the meta compound is not affected by the... 

The chemical properties of chromic oxide.—E. D. Clarke said that chromic oxide is not decomposed by the oxyhydrogen blowpipe flame and J. J. Berzelius found that it is not decomposed by hydrogen at a red-heat. For the electroxidation of chromic oxide, vide chromic acid, etc. According to R. Saxon traces of chromic acid are formed by the anodic oxidation of chromic oxide in pure water the addition of manganese dioxide to the chromic oxide increases slightly the yield of chromic acid. Much more rapid oxidation ensues in the presence of calcium or potassium hydroxide or both. In soln. of alkali chlorides containing a little chrome-alum, chromic oxide is rapidly oxidized at the anode to chromic acid. 

Other physical properties, such as air permeability, interfiber pore size and porosity, were also studied. Activated carbon nanofibers were produced from eleetrospun PAN by chemical activation with potassium hydroxide (KOH) as the activating agent. They were characterized by morphology, Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller... 

In addition to the equipment properties and selected operating conditions, the process performance depends to a large extent on the state of the active solvent component(s). Commonly nsed solvents include physical solvents like methanol (Rectisol) and the dimethyl ethers of polyethylene glycol (Selexol), chemical solvents like aqneous solutions of carbonates such as K2CO3 and Na2C03, of amino acid salts such as mixtures of potassium hydroxide and alanine or tanrine, and especially of alkanolamines such as mono-ethanolamine (MEA), di-ethanolamine (DEA), (activate) methyl-di-ethanolamine (MDEA), di-isopropanolamine (DIPA), di-glycolamine (DGA), 2-amino-2-methyl-l-propanol (AMP), and piperazine (PZ) (1). 

Kim and Yang [14] prepared ACNF from electro spun PAN nano fibers activated in steam at 700-800 °C and found that the specific surface area of the ACNF activated at 700 °C was the highest but the Mesopore volume fraction was the lowest. However, the work by Lee et al. [38] showed an opposite result. Song et al. [21] investigated the effect of activation time on the formation of ACNF (ultra-thin PAN fiber based) activated in steam at 1000 °C. Ji et al. [39] made mesoporous ACNF produced from electros-pun PAN nano fibers through physical activation with silica and conducted chemical activations by potassium hydroxide and zinc chloride to increase specific surface area and pore volume of ACNF [40]. It must be pointed out that different methods and conditions of activation lead to very different physical properties and adsorption capacities for ACNF. 

Lee LY, Lee SF. et ah. Effects of potassium hydroxide post-treatments on the field-emission properties of thermal chemical vapor deposited carbon nanotubes. Journal of Nanoscience and Nanotechnology, 2011. 11(12) 11185-11189. 

Caustic Potash Solution — (I) Chemical Designations — Synonyms Potassium Hydroxide Solution Lye Otemical Formula KOH—H O (ii) Observable Characteristics — Physical State (as normally shipped) Liquid Cobr Colorless Odor None (iii) Physical and Chemical Properties — Physical State at 15 X and 1 atm. Liquid Molecular Weight Not pertinent Boiling Point at 1 atm. >266, > 130, >403 Freezing Point Not pertinent Critical Temperature Not pertinent Critical Pressure Not pertinent Specific Gravity 1.45 - 1.50 at 20° C (liquid) Vapor (Gas) Density Not pertinent Ratio of Specific Heats of Vapor (Gas) Not pertinent Latent Heat... 

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