Decomposition moisture

Pure nitroglycerin is a stable Hquid at temperate conditions. It decomposes above 60°C to form nitric oxides which in turn catalyze further decomposition. Moisture increases the rate of decomposition under these conditions. Double- and multibase propellants containing nitroglycerin have substantially shorter stabiHty Hves at 65 and 80°C than do single-base propellants. The decomposition of nitroglycerin proceeds as... 

Air drying removes most of the surface moisture of coal, while a temperature of approximately 107°C (225°F) is needed to remove inherent moisture. At temperatures of approximately 200 to 300°C (392 to 572°F), moisture from the decomposition of organic materials is driven off, but water of hydration requires a considerable amount of energy for expulsion. For example, the water of hydration in clay minerals may require a temperature in excess of 500°C (932°F). However, the issues of decomposition moisture and water of hydration of mineral matter are not usually dealt with in conventional analysis because the temperatures specified in the test methods for moisture determination are well below those needed to remove such moisture. 

The various forms of moisture in coal are described according to the manner in which they are measured by some prescribed standard method. These forms are (1) inherent moisture, (2) surface or free moisture, (3) total moisture, (4) air-dry loss moisture, (5) residual moisture, (6) as-received moisture, (7) decomposition moisture, and (8) water of hydration of mineral matter. 

HIDROXILAMINA (Spanish) (7803-49-8) A powerful reducing agent. Aqueous solution is a base. Contact with water or steam causes decomposition to ammonium hydroxide, nitrogen, and hydrogen. Contaminants and/or elevated temperatures above (reported at 158°F/70°C and 265°F/129°C) can cause explosive decomposition. Moisture in air or carbon dioxide may cause decomposition. Violent reaction with oxidizers, strong acids, copper(II) sulfate, chromium trioxide, potassium dichromate, phosphorus chlorides, metals calcium, sodium, zinc. Incompatible with carbonyls, pyridine. Forms heat-sensitive explosive mixtures with calcium, zinc powder, and possibly other finely divided metals. Aqueous solution incompatible with organic anhydrides, acrylates, alcohols, aldehydes, alkylene oxides, substituted allyls, carbonyls, cellulose nitrate, cresols, caprolactam solution, epichlorohydrin, ethylene dichloride, glycols, isocyanates, ketones, nitrates, phenols, pyridine, vinyl acetate. Attacks aluminum, copper, tin, and zinc. 

Decomposition moisture water held within the coal s decomposed organic compounds... 

Figure 9.15 shows an example of CAF found in one test vehicle. In this case, the pathway formed between individual filaments of the glass cloth, either because they had not been sufficiently coated with resin or because resin decomposition, moisture, or other volatile compounds created a void. 

Thermal analysis has been used in a variety of areas including studies on thermal decomposition, moisture determination, volatile compounds, thermal oxidation, reaction kinetics, crystallization, phase diagrams, specific heat determination, vitreous transition determination, and storage time determination, among others [12]. 

Many materials need to be dried prior to their analysis to remove residual moisture. Depending on the material, heating to a temperature of 110-140 °C is usually sufficient. Other materials need to be heated to much higher temperatures to initiate thermal decomposition. Both processes can be accomplished using a laboratory oven capable of providing the required temperature. 

Electrical trees consist of visible permanent hoUow channels, resulting from decomposition of the material, and show up clearly in polyethylene and other translucent soHd dielectrics when examined with an optical microscope. Eresh, unstained water trees appear diffuse and temporary. Water trees consist of very fine paths along which moisture has penetrated under the action of a voltage gradient. Considerable force is required to effect this... 

Anhydrous oxaUc acid normally melts and simultaneously decomposes at 187°C. Sublimation starts at slightly below 100°C and proceeds rapidly at 125°C partial decomposition takes place during sublimation at 157°C. Anhydrous oxaUc acid is hygroscopic and thus absorbs moisture in the air to form the dihydrate. 

Because of the delay in decomposition of the peroxide, oxygen evolution follows carbon dioxide sorption. A catalyst is required to obtain total decomposition of the peroxides 2 wt % nickel sulfate often is used. The temperature of the bed is the controlling variable 204°C is required to produce the best decomposition rates (18). The reaction mechanism for sodium peroxide is the same as for lithium peroxide, ie, both carbon dioxide and moisture are required to generate oxygen. Sodium peroxide has been used extensively in breathing apparatus. 

Chemical Properties. Anhydrous sodium dithionite is combustible and can decompose exothermically if subjected to moisture. Sulfur dioxide is given off violentiy if the dry salt is heated above 190°C. At room temperature, in the absence of oxygen, alkaline (pH 9—12) aqueous solutions of dithionite decompose slowly over a matter of days. Increased temperature dramatically increases the decomposition rate. A representation of the decomposition chemistry is as follows ... 

Cyclopentadienyltitanium Compounds with Other Carbon Titanium Links. Cyclopentadienyltitanium trichloride and, particularly, CpgTiClg react with RLi or with RAl compounds to form one or more R—Ti bonds. As noted, the Cp groups stabilize the Ti—R bond considerably against thermal decomposition, although the sensitivity to air and moisture remains. Depending on the temperature, mole ratio, and stmcture of R, reduction of Ti(IV) may be a serious side reaction, which often has preparative value for Cp Ti(Ill) compounds (268,274,275). 

Beryllium Nitride. BeryUium nitride [1304-54-7], Be N2, is prepared by the reaction of metaUic beryUium and ammonia gas at 1100°C. It is a white crystalline material melting at 2200°C with decomposition. The sublimation rate becomes appreciable in a vacuum at 2000°C. Be2N2 is rapidly oxidized by air at 600°C and like the carbide is hydrolyzed by moisture. The oxide forms on beryllium metal in air at elevated temperatures, but in the absence of oxygen, beryllium reacts with nitrogen to form the nitride. When hot pressing mixtures of beryUium nitride and sUicon nitride, Si N, at 1700°C, beryllium sUicon nitride [12265-44-0], BeSiN2, is obtained. BeSiN2 may have appHcation as a ceramic material. 

Urea—formaldehyde (UF) resias commonly were used ia the past. However, because of the lack of moisture resistance and the potential for the resias to hydroly2e ia the presence of moisture and decompose iato urea and formaldehyde, they are not used as much now. Governmental regulations are under development that eliminate the use of UF resia ia wood products. This would limit the exposure of the pubHc to formaldehyde, a Hsted carciaogen, formed by the decomposition of UF resia. Today most wood products use pheaol—formaldehyde (pheaoHc) resias, but urethane-based resias are becoming more common. 

Anhydrite also has several common classifications. Anhydrite I designates the natural rock form. Anhydrite 11 identifies a relatively insoluble form of CaSO prepared by high temperature thermal decomposition of the dihydrate. It has an orthorhombic lattice. Anhydrite 111, a relatively soluble form made by lower temperature decomposition of dihydrate, is quite unstable converting to hemihydrate easily upon exposure to water or free moisture, and has the same crystal lattice as the hemihydrate phase. Soluble anhydrite is readily made from gypsum by dehydration at temperatures of 140—200°C. Insoluble anhydrite can be made by beating the dihydrate, hemihydrate, or soluble anhydrite for about 1 h at 900°C. Conversion can also be achieved at lower temperatures however, longer times are necessary. 

Solid Sta.te. The stabiHty of neutral calcium hypochlorite is primarily a function of moisture, lime, impurities, and temperature. Product containing - 7% water may lose 2—3% av CI2 during the first year when stored in warehouses without temperature control in moderate climates. Decomposition produces CaCl2, Ca(C102)2, and O2. 

By contrast, decomposition of dibasic calcium hypochlorite begins at 265° C to give Ca(OH)2, CaCl, and O2. Dibasic magnesium hypochlorite exhibits a high degree of stabiUty to moisture as shown by the following relative available chlorine losses at 24°C and 80% rh for 60 d Mg(OCl)2 2Mg(OH)2 2%,... 

Methylene chloride is one of the more stable of the chlorinated hydrocarbon solvents. Its initial thermal degradation temperature is 120°C in dry air (1). This temperature decreases as the moisture content increases. The reaction produces mainly HCl with trace amounts of phosgene. Decomposition under these conditions can be inhibited by the addition of small quantities (0.0001—1.0%) of phenoHc compounds, eg, phenol, hydroquinone, -cresol, resorcinol, thymol, and 1-naphthol (2). Stabilization may also be effected by the addition of small amounts of amines (3) or a mixture of nitromethane and 1,4-dioxane. The latter diminishes attack on aluminum and inhibits kon-catalyzed reactions of methylene chloride (4). The addition of small amounts of epoxides can also inhibit aluminum reactions catalyzed by iron (5). On prolonged contact with water, methylene chloride hydrolyzes very slowly, forming HCl as the primary product. On prolonged heating with water in a sealed vessel at 140—170°C, methylene chloride yields formaldehyde and hydrochloric acid as shown by the following equation (6). 

Stabilized tetrachloroethylene, as provided commercially, can be used in the presence of air, water, and light, in contact with common materials of constmction, at temperatures up to about 140°C. It resists hydrolysis at temperatures up to 150°C (2). However, the unstabilized compound, in the presence of water for prolonged periods, slowly hydrolyzes to yield trichloroacetic acid [76-03-9] and hydrochloric acid. In the absence of catalysts, air, or moisture, tetrachloroethylene is stable to about 500°C. Although it does not have a flash point or form flammable mixtures in air or oxygen, thermal decomposition results in the formation of hydrogen chloride and phosgene [75-44-5] (3). 

The specific electrical conductivity of dry coals is very low, specific resistance 10 ° - ohm-cm, although it increases with rank. Coal has semiconducting properties. The conductivity tends to increase exponentially with increasing temperatures (4,6). As coals are heated to above ca 600°C the conductivity rises especially rapidly owing to rearrangements in the carbon stmcture, although thermal decomposition contributes somewhat below this temperature. Moisture increases conductivity of coal samples through the water film. 

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