Decomposition carbon dioxide

An example of a solid in this category is p-aminobenzoic acid, which decomposes into aniline and carbon dioxide. Decomposition... 

The endothermic plasma-chemical process of carbon dioxide decomposition, illustrated in Fig. 5-1, can be presented by the summarizing formula... 

Ma, B., Balachandran, U., Chao, C. C., Park, J. H., Segre, C. U. (1997). Oxygen permeation in Sr—Fe—Co—O dense cetamic membranes. British Ceramic Transactions, 73, 169—177. Mahesh, S., Akira, K. (2010). Carbon dioxide decomposition by plasma methods and apphcation of high energy and high density plasmas in material processing and nano-stmctures. Transactions of JWRI39, 11—25. 

If the hydrogencarbonate is in solution and the cation is Ca or Mg. the insoluble carbonate is precipitated this reaction may be used, therefore, to remove hardness in water by precipitation of Ca or Mg ions.) The ease of decomposition of hydrogencar-bonates affords a test to distinguish between a hydrogencarbonate and a carbonate carbon dioxide is evolved by a hydrogencarbonate, but not by a carbonate, if it is heated, either as the solid or in solution, on a boiling water bath. 

If the reaction mixture used in the above preparation of formic acid is heated to 190-200°, the glyceryl monoformate which has escaped hydrolysis undergoes decomposition, with the loss of carbon dioxide and water, and the... 

The complete assembly for carrying out the catalytic decomposition of acids into ketones is shown in Fig. Ill, 72, 1. The main part of the apparatus consists of a device for dropping the acid at constant rate into a combustion tube containing the catalyst (manganous oxide deposited upon pumice) and heated electrically to about 350° the reaction products are condensed by a double surface condenser and coUected in a flask (which may be cooled in ice, if necessary) a glass bubbler at the end of the apparatus indicates the rate of decomposition (evolution of carbon dioxide). The furnace may be a commercial cylindrical furnace, about 70 cm. in length, but it is excellent practice, and certainly very much cheaper, to construct it from simple materials. 

The decomposition of a glycidic ester to an aldehyde and carbon dioxide may involve the formation of a quasi six-membered ring, followed by the shift of three electron pairs ... 

Decomposition Reactions. Minute traces of acetic anhydride are formed when very dry acetic acid is distilled. Without a catalyst, equiUbrium is reached after about 7 h of boiling, but a trace of acid catalyst produces equiUbrium in 20 min. At equiUbrium, about 4.2 mmol of anhydride is present per bter of acetic acid, even at temperatures as low as 80°C (17). Thermolysis of acetic acid occurs at 442°C and 101.3 kPa (1 atm), leading by parallel pathways to methane [72-82-8] and carbon dioxide [124-38-9] and to ketene [463-51-4] and water (18). Both reactions have great industrial significance. 

Triiodoacetic acid [594-68-3] (I CCOOH), mol wt 437.74, C2HO2I3, mp 150°C (decomposition), is soluble in water, ethyl alcohol, and ethyl ether. It has been prepared by heating iodic acid and malonic acid in boiling water (63). Solutions of triiodoacetic acid are unstable as evidenced by the formation of iodine. Triiodoacetic acid decomposes when heated above room temperature to give iodine, iodoform, and carbon dioxide. The sodium and lead salts have been prepared. 

Dehydration or Chemical Theory. In the dehydration or chemical theory, catalytic dehydration of ceUulose occurs. The decomposition path of ceUulose is altered so that flammable tars and gases are reduced and the amount of char is increased ie, upon combustion, ceUulose produces mainly carbon and water, rather than carbon dioxide and water. Because of catalytic dehydration, most fire-resistant cottons decompose at lower temperatures than do untreated cottons, eg, flame-resistant cottons decompose at 275—325°C compared with about 375°C for untreated cotton. Phosphoric acid and sulfuric acid [8014-95-7] are good examples of dehydrating agents that can act as efficient flame retardants (15—17). 

Because PTFE resins decompose slowly, they may be heated to a high temperature. The toxicity of the pyrolysis products warrants care where exposure of personnel is likely to occur (120). Above 230°C decomposition rates become measurable (0.0001% per hour). Small amounts of toxic perfiuoroisobutylene have been isolated at 400°C and above free fluorine has never been found. Above 690°C the decomposition products bum but do not support combustion if the heat is removed. Combustion products consist primarily of carbon dioxide, carbon tetrafluoride, and small quantities of toxic and corrosive hydrogen fluoride. The PTFE resins are nonflammable and do not propagate flame. 

Anhydrous, monomeric formaldehyde is not available commercially. The pure, dry gas is relatively stable at 80—100°C but slowly polymerizes at lower temperatures. Traces of polar impurities such as acids, alkahes, and water greatly accelerate the polymerization. When Hquid formaldehyde is warmed to room temperature in a sealed ampul, it polymerizes rapidly with evolution of heat (63 kj /mol or 15.05 kcal/mol). Uncatalyzed decomposition is very slow below 300°C extrapolation of kinetic data (32) to 400°C indicates that the rate of decomposition is ca 0.44%/min at 101 kPa (1 atm). The main products ate CO and H2. Metals such as platinum (33), copper (34), and chromia and alumina (35) also catalyze the formation of methanol, methyl formate, formic acid, carbon dioxide, and methane. Trace levels of formaldehyde found in urban atmospheres are readily photo-oxidized to carbon dioxide the half-life ranges from 35—50 minutes (36). 

There are three essential factors in the thermal decomposition of limestone (/) the stone must be heated to the dissociation temperature of the carbonates (2) this minimum temperature (but in practice a higher temperature) must be maintained for a certain duration and (J) the carbon dioxide evolved must be removed rapidly. 

Lithium Oxide. Lithium oxide [12057-24-8], Li20, can be prepared by heating very pure lithium hydroxide to about 800°C under vacuum or by thermal decomposition of the peroxide (67). Lithium oxide is very reactive with carbon dioxide or water. It has been considered as a potential high temperature neutron target for tritium production (68). 

Subsequent studies (63,64) suggested that the nature of the chemical activation process was a one-electron oxidation of the fluorescer by (27) followed by decomposition of the dioxetanedione radical anion to a carbon dioxide radical anion. Back electron transfer to the radical cation of the fluorescer produced the excited state which emitted the luminescence characteristic of the fluorescent state of the emitter. The chemical activation mechanism was patterned after the CIEEL mechanism proposed for dioxetanones and dioxetanes discussed earher (65). Additional support for the CIEEL mechanism, was furnished by demonstration (66) that a linear correlation existed between the singlet excitation energy of the fluorescer and the chemiluminescence intensity which had been shown earher with dimethyl dioxetanone (67). 

Decomposition and Decarboxylation. Maleic anhydride undergoes anaerobic thermal decomposition in the gas phase in a homogeneous unimolecular reaction to give carbon monoxide, carbon dioxide, and acetylene [74-86-2] in equimolar amounts. The endothermic... 

Reactions. Heating an aqueous solution of malonic acid above 70°C results in its decomposition to acetic acid and carbon dioxide. Malonic acid is a useful tool for synthesizing a-unsaturated carboxyUc acids because of its abiUty to undergo decarboxylation and condensation with aldehydes or ketones at the methylene group. Cinnamic acids are formed from the reaction of malonic acid and benzaldehyde derivatives (1). If aUphatic aldehydes are used acryhc acids result (2). Similarly this facile decarboxylation combined with the condensation with an activated double bond yields a-substituted acetic acid derivatives. For example, 4-thiazohdine acetic acids (2) are readily prepared from 2,5-dihydro-l,3-thiazoles (3). A further feature of malonic acid is that it does not form an anhydride when heated with phosphorous pentoxide [1314-56-3] but rather carbon suboxide [504-64-3] [0=C=C=0], a toxic gas that reacts with water to reform malonic acid. 

Drying a.nd Calcination. The simplest pyrometaHurgical operation is the evaporation of free water and the decomposition of hydrates and carbonates. A typical reaction is the decomposition of pure limestone [1317-65-3] CaCO, to calcium oxide [1305-78-8] and carbon dioxide ... 

Alkaline solutions of mononitroparaffins undergo many different reactions when stored for long periods, acidified, or heated. Acidification of solutions of mononitro salts is best effected slowly at 0°C or lower with weak acids or buffered acidic mixtures, such as acetic acid—urea, carbon dioxide, or hydroxyl ammonium chloride. If mineral acids are used under mild conditions, eg, dilute HCl at 0°C, decomposition yields a carbonyl compound and nitrous oxide (Nef reaction). 

Carbonate Decomposition. The carbonate content of Green River oil shale is high (see Table 4). In addition, the northern portion of the Piceance Creek basin contains significant quantities of the carbonate minerals nahcoUte and dawsonite. The decomposition of these minerals is endothermic and occurs at ca 600—750°C for dolomite, 600—900°C for calcite, 350—400°C for dawsonite, and 100—120°C for nahcohte. Kinetics of these reactions have been studied (19). Carbon dioxide, a product of decomposition, dilutes the off-gases produced from retorting processes at the above decomposition temperatures. 

On rapid heating, oxaUc acid decomposes to formic acid, carbon monoxide, carbon dioxide, and water (qv). When it is heated ia 96 wt % glycerol solution at 88—121°C, the presence of formic acid ia the decomposed product tends to accelerate the decomposition reaction. Formic acid is thus... 

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. 

Decomposition products from primary and secondary dialkyl peroxides include aldehydes, ketones, alcohols, hydrogen, hydrocarbons, carbon monoxide, and carbon dioxide (44). 

Thermal decomposition of hydroxyalkyl hydroperoxyalkyl peroxides produces mixtures of starting carbonyl compounds, mono- and dicarboxyHc acids, cycHc diperoxides, carbon dioxide, and water. One specific hydroxyalkyl hydroperoxyalkyl peroxide from cyclohexanone (2, X = OH, Y = OOH) is a soHd that is produced commercially as a free-radical initiator and bleaching agent (see Table 5). On controlled decomposition, it forms 1,12-dodecanedioic acid (150). 

The first-order decomposition rates of alkyl peroxycarbamates are strongly influenced by stmcture, eg, electron-donating substituents on nitrogen increase the rate of decomposition, and some substituents increase sensitivity to induced decomposition (20). Alkyl peroxycarbamates have been used to initiate vinyl monomer polymerizations and to cure mbbers (244). They Hberate iodine quantitatively from hydriodic acid solutions. Decomposition products include carbon dioxide, hydrazo and azo compounds, amines, imines, and O-alkyUiydroxylarnines. Many peroxycarbamates are stable at ca 20°C but decompose rapidly and sometimes violently above 80°C (20,44). 

Ammonium bicarbonate, sp gr 1.586, formula wt 79.06, is the only compound in the NH —CO2—H2O system that dissolves in water without decomposition. SolubiUty in 100 g of H2O ranges from 11.9 g at 0°C to 59.2 g/100 g of H2O at 60°C (8). The heat of formation from gaseous ammonia and carbon dioxide andUquid water is 126.5 kj/mol (30.2 kcal/mol). Ammonium bicarbonate is manufactured by passing carbon dioxide gas... 

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