Nitration heat of reaction

Nitration of cellulose in the gaseous phase Nitration with nitronium chloride Kinetics of nitration. Heat of reaction Heat of nitration... 

The highly exothermic nature of the butane-to-maleic anhydride reaction and the principal by-product reactions require substantial heat removal from the reactor. Thus the reaction is carried out in what is effectively a large multitubular heat exchanger which circulates a mixture of 53% potassium nitrate [7757-79-1/, KNO 40% sodium nitrite [7632-00-0], NaN02 and 7% sodium nitrate [7631-99-4], NaNO. Reaction tube diameters are kept at a minimum 25—30 mm in outside diameter to faciUtate heat removal. Reactor tube lengths are between 3 and 6 meters. The exothermic heat of reaction is removed from the salt mixture by the production of steam in an external salt cooler. Reactor temperatures are in the range of 390 to 430°C. Despite the rapid circulation of salt on the shell side of the reactor, catalyst temperatures can be 40 to 60°C higher than the salt temperature. The butane to maleic anhydride reaction typically reaches its maximum efficiency (maximum yield) at about 85% butane conversion. Reported molar yields are typically 50 to 60%. 

Nitrations are highly exothermic, ie, ca 126 kj/mol (30 kcal/mol). However, the heat of reaction varies with the hydrocarbon that is nitrated. The mechanism of a nitration depends on the reactants and the operating conditions. The reactions usually are either ionic or free-radical. Ionic nitrations are commonly used for aromatics many heterocycHcs hydroxyl compounds, eg, simple alcohols, glycols, glycerol, and cellulose and amines. Nitration of paraffins, cycloparaffins, and olefins frequentiy involves a free-radical reaction. Aromatic compounds and other hydrocarbons sometimes can be nitrated by free-radical reactions, but generally such reactions are less successful. 

In the last few years several modifications to the traditional mixed acid nitration procedure have been reported. An adiabatic nitration process was developed for the production of nitrobenzene (9). This method eliminated the need to remove the heat of reaction by excessive cooling. The excess heat can be used in the sulfuric acid reconcentration step. An additional advantage of this method is the reduction in reaction times to 0.5—7.5 minutes. 

According to Ref 50, nitration is carried out in an adiabatic nitrator in which the heat of reaction is utilized to vaporize the nitric acid. 

The spent acid compn is 12.6/70.8/16.6 nitric acid/sulfuric acid/water, or 83.4% total acid and 15.1% nitric acid based on total acid. The total heat of reaction AHt = AHn + AHj where AHn is the heat of nitration, ie, the heat of... 

Igniters. A pellet composed of 26.5% K. perchlorate, 16.6% Ba nitrate, 53,9% 50/50 Zr/Ni alloy, and 3.0% et cellulose can be used to ignite solid propint grains (Ref 25), A series of mixts of K perchlorate with powd metals and other oxidizable mat were examined as substitutes for BikPdr as a gun primer. Most of the mixts tested were found to be satisfactory and to be compatible with brass and other metals (Ref 9) Incendiary Compositions. Stoichiometric mixts of K perchlorate with metals and oxidizable mat have been proposed as incendiaries of the Thermit type and have heats of reaction as follows Al dust 2504, powd Mg 2429. red P 1477, powd S 705 and powd C (lampblack) 1118cal/g (Ref 4). A mixt of 12.5% K perchlorate, 75% powd Zr, and 12,5% of a 50/50 Al/Mg alloy is reported to be a readily-ignited incendiary (Ref 20). Mixts of powd Al and/or powd Fe with K perchlorate with 1.5—2% NC as a binder are also good incendiaries (Ref 35). 

In any event, it is clear from Table 3.3 that potassium nitrate is inferior to potassium perchlorate and the ammonium salts in terms of the volume of gas liberated at STP, the heat of reaction with carbon and the minimalisation of smoke (i.e. solid products). 

The reaction is carried out in aqueous phase using a slight excess of nitric acid. The heat of reaction is utilized to evaporate the water. Also, evaporation may be carried out under vacuum. Alternatively, solid ammonium nitrate is obtained by crystallization from a concentrated solution. The particle size of the dry product may be controlled by vacuum crystallization, granulation or... 

Sodium nitrate % Magnesium Linear burning rate, mm/sec Heat of reaction, kcal/gram... 

In this reaction 779 kcal/kg is evolved, the gas volume V0 amounts to 240 l./kg, and the calculated temperature is 2700°C. For mixture consisting of 70% potassium nitrate and 30% charcoal (Sulphurless Gunpowder SFG.I2) the heat of reaction is 670 20 kcal/kg, according to Thomas [27]. 

A classical paper on the composition of the explosion products of blackpowder and of the heat of reaction was published by Bunsen and Shishkov [41]. They ascertained that the gases formed constitute 31% of the charge and contain approximately 50% C02,40% N2,4% CO and lesser amounts (0.5-1.5%) of H2,02, H2S. Solid products consist of potassium carbonate, sulphate, thiosulphate, sulphide and nitrate with traces of potassium rhodanate, sulphur and carbon. These authors also detected the presence of ammonium carbonate. 

Nitrations are highly exothermic, i.e., ca 126 kJ/mol (30 keal/raol) However, the heat of reaction varies with the hydrocarbon that is nitrated. The mechanism of a nitration depends on the reactants and [he... 

This method was used by Freeman (Ref 8) to determine the heats of reaction of the nitrite-nitrate oxidation 5.2 Heat Capacities 5.2.1 By Calorimetry... 

PbF2 (c). Guntz1 found 2.2 for the heat of reaction of aqueous lead nitrate with aqueous hydrofluoric acid. This gives for PbF2 (c), Qf=159.5. From equilibrium data, Jellinek and Rudat1 calculated Qf=156. 

PbS (c). Berthelot14 found the heats of reaction of aqueous hydrogen sulfide to be 13.34 and 11.34 with aqueous lead nitrate and aqueous lead acetate, respectively whence, for PbS (c), Qf=24.8 and 20.6, respectively. Thomsen15 found Q=30.98 for the reaction between aqueous lead nitrate and aqueous sodium sulfide whence, for PbS(c), Qf=22.5. From equilibrium data, Jellinek and Zakowski1 deduced Qf=20.0 Watanabe2 obtained 22.85 Jellinek and Deubel,1 26.2. 

PbC204 (c). Berthelot12 measured the heat of reaction between aqueous lead nitrate and aqueous potassium oxalate to be 9.3. 

Ag2Se04 (c). Metzner1 2 measured the heat of reaction of aqueous silver nitrate with aqueous potassium selenate to be 8.48. 

Ag2C2 (c). Berthelot and Delepine1 measured the heat of reaction of acetylene with 2 AgN03 2 NH3(c), and the heat of solution of Ag2C2(c) in aqueous silver nitrate. 

PbCr04 (c). Goldblum and Stoffella1 measured the heat of reaction of aqueous potassium chromate with aqueous lead nitrate to be 10.6. For the heat of the reaction of aqueous lead chloride with aqueous potassium chromate, Roth, Schwrartz, and Buchner1 found Q = 11.16. 

Mg(N03)2 (aq.). Thomsen15 measured the heat of reaction of MgS04 (200) with Ba(NO3)2(200) to be 4.94 whence, for Mg(NO3)2(400), Qf=208.8. Data on the heat of dilution of aqueous magnesium nitrate were reported by Thomsen,15 Dunnington and Hoggard,1 Lange and Streeck,2 and Hammerschmid and Lange.1... 

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