Temperature hydrolysis

Alkylated aromatics have excellent low temperature fluidity and low pour points. The viscosity indexes are lower than most mineral oils. These materials are less volatile than comparably viscous mineral oils, and more stable to high temperatures, hydrolysis, and nuclear radiation. Oxidation stabihty depends strongly on the stmcture of the alkyl groups (10). However it is difficult to incorporate inhibitors and the lubrication properties of specific stmctures maybe poor. The alkylated aromatics also are compatible with mineral oils and systems designed for mineral oils (see Benzene Toulene Xylenes and ethylbenzene). ... 

Only Pu(III) oxyhahdes (PuOF, PuOCl, PuOBr, and PuOI) and Pu(VI) oxyhaHdes (PUO2F2, PuOF, and PUO2CI2 6H20) are known. Of these the most important are PuOCl, which is the stable product of hydrolysis of PUCI3 (s) with H2O (g) (157), and PUO2F2, which is the product of low temperature hydrolysis of PuF and one of the products of room temperature hydrolysis of PuF (158—160). 

The high temperature hydrolysis of sulfur in alkaline solutions also produces thiosulfates ... 

Another event which may occur is hydrolysis. This is a chemical reaction between the plastic and water. It occurs extremely slowly at room temperature but can be significant at moulding temperatures. Hydrolysis causes degradation, reduction in properties (such as impact strength) and it is irreversible. Table 4.3 indicates the sensitivity of plastics to moisture. Note that generally extrusion requires a lower moisture content than injection moulding to produce good quality products. 

Dilute aqueous solutions of sulfamic acid are stable for many months at room temperature but at higher temperatures hydrolysis to NH4[HS04] sets in. Alkali metal salts are stable in neutral and... 

The formation of oxide compounds as a result of the thermal treatment of oxyfluorides is due to high temperature hydrolysis and reduction-oxidation processes. 

High temperature hydrolysis of EDTA is accelerated by the presence of oxygen, and chelant corrosion may take place in the presence of oxygen and a chelant overfeed. (See Section 7.4.1 for more details). Key points are ... 

Thermal oxidation is another alternative for destroying cyanide. Thermal destruction of cyanide can be accomplished through either high-temperature hydrolysis or combustion. At temperatures between 140°C and 200°C and a pH of 8, cyanide hydrolyzes quite rapidly to produce formate and ammonia.23 Pressures up to 100 bar are required, but the process can effectively treat waste streams over a wide concentration range and is applicable to both rinsewater and concentrated solutions22 ... 

Where aqueous NMS solutions are used as the feedstock, higher NMP 2P product ratios are generally observed. However, when aqueous NMS feed is run at 265°C, free methanol is observed in the earliest product samples. Loss of the methyl group from NMS via high temperature hydrolysis apparently becomes significant at this temperature. With aqueous NMS as the feedstock, and when the reaction temperature is lowered to 200°C, NMP 2P molar product ratios as high 67 1 were observed for the more active 2.5%Rh2.5%Re/C catalyst. At the same temperature, even the less active 2.5%Rh2.5%Zr/C catalyst displayed a respectable NMP 2P product ratio of 38 1. 

The carbon tetrachloride vapor carries with it any moisture that may be present. If this were not removed at a relatively low temperature, hydrolysis of the chloride would take place, with the formation of sulfonic acid which would promote decomposition of the sulfochloride during its distillation. 

The method used here was essentially that described by Stober et al. (4) which involves the room-temperature hydrolysis of tetra-ethylsilicate in ethanol containing varying amounts of ammonia and water, the latter two components control the final particle morphology and size. The method has been modified slightly by Bridger (2,5) and by van Helden and Vrij (3). 

After being stirred for 2 hours at — 15°C, the reaction was quenched with water (6 mL) and the mixture was stirred for 30 minutes at this temperature. The solution was warmed to room temperature. Hydrolysis of the tartrate was then effected by adding an aqueous solution of sodium hydroxide (30 %) saturated with sodium chloride (6 mL) and stirring vigorously for 1 hour. 

Thermal dealumination. The method involves calcination of the ammonium (or hydrogen) form of the zeolite at relatively high temperatures (usually over 500°C) in the presence of steam. This results in the expulsion of tetrahedral aluminum from the framework into non-framework positions, but does not remove the aluminum from the zeolite. The process consists essentially in a high-temperature hydrolysis of Si-O-Al bonds and leads to the formation of neutral and cationic aluminum species (Figure 1A). 

The rapid oxidation of Fe " close to the surface and in the presence of a fair supply of organic matter and dissolved Si, conditions which hinder crystallization, leads to ferrihydrite instead of goethite. The ferrihydrite is, however, often associated with goethite and it is still unknown whether the two minerals have formed simultaneously or in sequence. Simultaneous formation seems more likely for two reasons in the first place, low-temperature hydrolysis of Fe " or oxidation of Fe ", both, led to mixtures of the two oxides in different proportions if the rate of hydrolysis/oxidation was varied (Schwertmann et al. 1999 Schwertmann Cornell, 2000). Secondly, the transformation of ferrihydrite, especially in the presence of Si, appears to be extremely sluggish. 

Stability-. Stable at room temperature hydrolysis in water is rapid. 

At higher temperatures hydrolysis of the carboxonium ion and Baeyer-Villiger oxidation lead to the formation of acetone, methanol, and methyl acetate ... 

The reaction that is fundamental to the flux-reaction technique is the high-temperature hydrolysis of strontium chloride ... 

For compounds like TCA, for which both high temperature and room temperature hydrolysis rates have been measured and contaminant plumes have been observed over a considerable length of time, extrapolation using the Arrhenius parameters appears valid. In addition, apparent augmentation of reactivity in real environmental situations often can be rationalized in terms of additional reaction pathways, so that it is not necessary to invoke the non-validity of the extrapolation process. 

Many approaches have been taken to prepare colloidal doped semiconductor nanocrystals. For example, hot-injection methods have been used to synthesize colloidal Mn2+-doped CdSe (47, 48), ZnSe (49), and PbSe (50) colloidal nanocrystals. Colloidal ZnO DMS-QDs doped with Co2+, Ni2+, and Mn2+ have been prepared by low-temperature hydrolysis and condensation (51-54). Sol-gel methods have been used to prepare colloidal doped TiC>2 (55-57) and Sn02 (58-62) nanocrystals. Inverted micelle methods have been used for preparation of a range of doped II-VI sulfide DMS-QDs at low temperatures (63-68). A high-temperature lyothermal single-source method was used to synthesize Co2+- and Eu3+-doped CdSe nanocrystals (69, 70). Autoclaving has occasionally been used to induce crystallization at lower temperatures than reached under atmospheric pressures while retaining colloidal properties, for... 

Although there were several early reports of the existence of XeOF2, only that by Ogden et al. (338) was supported by experimental evidence. It was prepared as a yellow solid by the low-temperature hydrolysis of XeF4. It has since been prepared when condensed intimate mixtures of XeF4 and H20 (1 1.1 molar ratio) are allowed to warm to -80 to - 50°C (254). The bright-yellow, nonvolatile solid is stable up to -25°C but the compound is best handled below 40°C in a moisture-free atmosphere. More recently the preparations of XeOF2, Cs[XeOF )l,... 

When selecting polyurethanes for any application, a full understanding of the working conditions should be obtained to prevent overspecifying the grade and type. These conditions may include the interaction of temperature, hydrolysis, and wear in a dynamic situation. The limitations of polyurethanes also must be taken into account and some redesign carried out if needed. 

When arsonium salt 120-1 is treated with lithium aluminum hydride in tetra-hydrofurane at —70 °C copious evolution of hydrogen occurs and a red solution is obtained, whose color fades on warming to room temperature. Hydrolysis yields only 2-biphenylyl-2,2 -biphenylylenearsine (124). The same deep red solution and colorless hydrolysis product 124 are obtained when 2 -bromo-2-biphenylyl-2,2 -biphenylylenearsine (147) is first reacted with t-butyllithium in tetrahydrofurane... 

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