Hydroxide reaction

Pentaerythritol is produced by reaction of formaldehyde [50-00-0] and acetaldehyde [75-07-0] in the presence of a basic catalyst, generally an alkah or alkaline-earth hydroxide. Reaction proceeds by aldol addition to the carbon adjacent to the hydroxyl on the acetaldehyde. The pentaerythrose [3818-32-4] so produced is converted to pentaerythritol by a crossed Cannizzaro reaction using formaldehyde. All reaction steps are reversible except the last, which allows completion of the reaction and high yield industrial production. 

Methylene iodide [75-11-6], CH2I2, also known as diio dome thane, mol wt 267.87, 94.76% I, mp 6.0°C, and bp 181°C, is a very heavy colorless Hquid. It has a density of 3.325 g/mL at 20°C and a refractive index of 1.7538 at 4°C. It darkens in contact with air, moisture, and light. Its solubiHty in water is 1.42 g/100 g H2O at 20°C it is soluble in alcohol, chloroform, ben2ene, and ether. Methylene iodide is prepared by reaction of sodium arsenite and iodoform with sodium hydroxide reaction of iodine, sodium ethoxide, and hydroiodic acid on iodoform the oxidation of iodoacetic acid with potassium persulfate and by reaction of potassium iodide and methylene chloride (124,125). Diiodoform is used for determining the density and refractive index of minerals. It is also used as a starting material in the manufacture of x-ray contrast media and other synthetic pharmaceuticals (qv). 

Nickel Salts and Chelates. Nickel salts of simple organic acids can be prepared by reaction of the organic acid and nickel carbonate of nickel hydroxide reaction of the acid and a water solution of a simple nickel salt and, in some cases, reaction of the acid and fine nickel powder or black nickel oxide. 

Reaction of olefin oxides (epoxides) to produce poly(oxyalkylene) ether derivatives is the etherification of polyols of greatest commercial importance. Epoxides used include ethylene oxide, propylene oxide, and epichl orohydrin. The products of oxyalkylation have the same number of hydroxyl groups per mole as the starting polyol. Examples include the poly(oxypropylene) ethers of sorbitol (130) and lactitol (131), usually formed in the presence of an alkaline catalyst such as potassium hydroxide. Reaction of epichl orohydrin and isosorbide leads to the bisglycidyl ether (132). A polysubstituted carboxyethyl ether of mannitol has been obtained by the interaction of mannitol with acrylonitrile followed by hydrolysis of the intermediate cyanoethyl ether (133). 

The thermodynamic data pertinent to the corrosion of metals in aqueous media have been systematically assembled in a form that has become known as Pourbaix diagrams (11). The data include the potential and pH dependence of metal, metal oxide, and metal hydroxide reactions and, in some cases, complex ions. The potential and pH dependence of the hydrogen and oxygen reactions are also suppHed because these are the common corrosion cathodic reactions. The Pourbaix diagram for the iron—water system is given as Figure 1. 

Fluoride F Few major industrial water problems Reduces dental decay Alum coagulation Magnesium Hydroxide reaction Anion exchange Membrane separation... 

Although organosilanes appear to react slowly (if at all) with water alone, in the presence of acids or bases (e.g., alkali metal hydroxides), reactions to give a silanol and H2 are rapid, with bases being particularly powerful catalysts. The evolution of H2 in this type of reaction may be used as both a qualitative and a quantitative test for Si-H bonds, and the mechanism of the acid and the base hydrolysis has been discussed in detail (30,31). This hydrolytic method is not very common for the preparation of silanols that are to be isolated, because both acids and bases catalyze the condensation of silanols to siloxanes, and therefore, only compounds containing large substituents are conveniently made in this way. If an anhydrous alkali metal salt is used, a metal siloxide may be isolated and subsequently hydrolyzed to give the silanol [Eq. (10)] (32). 

If in the quaternary ion a /3-hydrogen is not available, as in tetramethyl-, benzyltrimethyl- or phenyltrimethylammonium hydroxide, reaction 4.101 cannot occur, but reaction 4.102 still can this means that the quaternary ammonium ions without a /1-hydrogen are appreciably more stable, so that the type of base concerned is mainly the commercially available one (in alcoholic solution) (CH3)4NOH appears especially attractive, although the (CH3)4N salts are less soluble in non-aqueous media than, for instance, (C4H9)4N salts. 

Figure 1.4 also shows two other reactions. In reaction 2, ammonia reacts with water to form ammonium hydroxide. Reaction 3 shows that ammonia can also be oxidized to form nitric acid from which all forms of nitrates can be produced. All three forms of nitrogen (ammonia, ammonium hydroxide, and nitrates in various forms) are commonly found in soil and can be added to soil to supply nitrogen to plants (see also Figure 6.5). This process thus opened up an inexpensive method of producing nitrogen compounds that would be used as fertilizers.

Figure 12.5 Zinc-hydroxide reaction mechanism for peptide hydrolysis by carboxypeptidase A. (Reprinted with permission from Lipscomb and Strater, 1996. Copyright (1996) American Chemical Society.)...

The reaction actually involves the sodium salt of bisphenol A since polymerization is carried out in the presence of an equivalent of sodium hydroxide. Reaction temperatures are in the range 50-95°C. Side reactions (hydrolysis of epichlorohydrin, reaction of epichlorohydrin with hydroxyl groups of polymer or impurities) as well as the stoichiometric ratio need to be controlled to produce a prepolymer with two epoxide end groups. Either liquid or solid prepolymers are produced by control of molecular weight typical values of n are less than 1 for liquid prepolymers and in the range 2-30 for solid prepolymers. 

Since thiolates are far more reactive than thiols (pK 8-9.5) in nucleophilic attack on coordinated NO, these rates are pH dependent [53]. The reaction of alkaline solutions of mercaptans with nitroprusside to yield reddish-purple solutions has long been used as a test for cysteine, glutathione or other thiol-containing compounds. However, if the solution is too basic, the nitroprusside/ hydroxide reaction becomes competitive [3]. 

The increase in alkylation efficiency of HEC with quaternary ammonium hydroxide is not limited to DPGE. Experiments were conducted in which HEC was alkylated with 1-bromohexadecane (cetyl bromide), 3-n-pentadecenyl phenyl glycidyl ether (PDPGE)14, or 1,2-epoxyhexadecane (C]6 a-olefin epoxide) in the presence of either sodium hydroxide or benzyltrimethylammonium hydroxide. As before, the molar A/HEC ratio was 0.50, and the water content of the diluent in the benzyltrimethylammonium hydroxide experiment was decreased to compensate for the higher water content of the base so that the final water content of both reactions was the same (14.4%). The hexadecyl content of the polymers was measured by gas chromatography. The sodium hydroxide mediated reaction of 1-bromohexadecane yielded a hexadecyl alkylation efficiency of 0.5%, while the benzyltrimethylammonium hydroxide reaction yielded a hexadecyl alkylation efficiency of 6.2%. A twelve-fold increase in the hexadecyl alkylation efficiency was observed in the reaction conducted with the quaternary ammonium hydroxide. 

This sensitivity to substitution of neutral hydrolysis means that the pH-independent reaction gradually becomes more important than the hydroxide reaction at the high pH end of the region, and becomes much more rapidly more important than acid-catalyzed hydrolysis at low pH. Thus from Fig. 13, the acid-catalyzed reaction can be seen to be significant for the hydrolysis of ethyl acetate between pH 4 and 5, and for phenyl acetate about pH 2 but for 2,4-dinitrophenyl acetate the acid-catalyzed reaction is not detectable at pH 1, and is presumably important only in relatively strong acid. It seems certain that this fast neutral hydrolysis is at any rate a partial explanation for the low efficiency of acid catalysis in the hydrolysis of very weakly basic esters, such as the trifluoroacetates and oxalates, in moderately concentrated acid (see p. 145). 

For example, when sulfonate esters are hydrolyzed with ieO-enriched hydroxide (Reaction 4.38) the product sulfonic acids contain ieO but the starting material recovered after 50 percent reaction does not.75 By the arguments outlined on p. 200 this might be evidence for either a one-step displacement or a two-step mechanism with the first step rate-determining. The latter is made more... 

The increased solubility of quartz in basic organic solvent systems appears to be caused by aqueous potassium hydroxide reaction at temperatures above the boiling point of the aqueous system alone. The organic solvent fraction serves as a substrate which permits attainment of elevated temperatures. Increasing the pressure at which basic aqueous reactions are performed would serve as an alternative method which would eliminate the need for addition of organic solvents. This prospect is especially attractive for in situ removal of silicates from oil shale since geothermal gradient and overburden may provide the elevated temperature and pressure necessary for efficient silicate removal. 

The sequence is not entirely clean in that some CH3CDO is also obtained. Probably this is due to incomplete inversion in the tosylate — hydroxide reaction resulting from O—S cleavage (with retention). 

Such a scenario of the kinetic task uses the Michaelis-Menten equation in Linuver-Berk coordinates to describe the methane hydroxidation reaction ... 

Procedure B. Solubilization with NaOH-ethanol was done following the procedures developed by Ouchi et al (11,12). In each experiment 24 grams of coal was reacted with 120 grams of ethanol and 40 grams of sodium hydroxide. Reactions were conducted in a stirred autoclave at 300°C and at 320°C, using a processing time of 100 minutes after the reaction temperature was reached. At the completion of the reaction, the reactor was cooled to room temperature. Distilled, deionized water was introduced inside the reactor, and the product was collected in two forms ... 

The monopotassium salt (103) and the dipotassium salt (105) can be prepared in quantitative yield from (101) and potassium hydroxide. Reaction of (105) in DMF with alkyl halides gives dialkylation products (106a) from benzyl bromide, (106b) from methyl iodide, (106c) from allyl bromide, and (106d) from 1-butyl bromide in low yield. 

When a salt is introduced to water (e.g., A1C13s), the charged metal (Al3+) has a strong tendency to react with H20 or OH" and forms various Al-hydroxy species. Metal-hydroxide reactions in solution exert two types of influences on metal-hydroxide solubility, depending on the quantity of hydroxyl supplied. They either decrease or increase metal solubility. The solubility of a particular metal-hydroxide mineral depends on its Ksp, quantity of available hydroxyl, and solution pH of zero net charge. For example, aluminum (Al3+) forms a number of hydroxy species in water as shown below ... 

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