Thomsons method

The process patented by the Thomsons in 1903 (J. M. Thomson and W. T. Thomson [15]) was used only in Great Britain, thou during World War I it was used to a lesser extent also in France. It has now been superceded by the use of nitrators with mechanical stirring. 

The principle features of Thomsons method are (/) immersing the cotton in the add, and (2) after nitration washing out the acid with water. 

The nitrator sketched in Fig. 143 is a cylindrical stoneware vessel of internal diameter 1.1m and depth 0.4 m, strengthened with an iron belt. Its conical bottom is fitted with an outlet pipe. A three-way valve is provided for evacuating and filling the vessel with acid. Inside the vessel there is a perforated stoneware plate to support the cotton charge. Twenty five to twenty nine centimeters above this plate supports carry a perforated aluminium plate 15 mm thick, which acts as a false 

Nitration in the Thomsons plant is carried out as follows. Some 500-540 kg of nitrating acid mixed in the ratio reported in Table 96 are introduced 

The nitration of cotton by the Thomsons method, as applied in France [14] 

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Pc mm. Critical pressure in mm. Where this was not obtained from the literature it is calculated as follows (Thomson method, private communication from George W. Thomson) The critical temperature is inserted in the Antoine equation, using the A, B, and C values to calculate the critical pressure. 

A, B, C The A, B, and C constants, except where given by the API reports, are calculated by means of the Thomson method [Chem. Revs. 38, 1-39 (1946)] using the determined boiling points at three different pressures. The three formulas for this are as follows ... 

Unstable esters formed during nitrating also undergo decomposition, when water is added. Nitrocotton prepared by Thomsons method is therefore more stable than the product obtained by other methods. Due to partial denitration, the solubility of the guncotton in an ether-alcohol solution is increased. 

The stabilization of guncotton produced by the Thomsons method is slightly less expensive, as this product is easier to purify. According to Robertson [2] 10 successive boiling and washing operations are to be carried out ... 

The water is changed after each boil. In spite of the relatively short time needed for stabilization, the Thomsons method is too expensive. 

Thomson s Method to Calculate Antoine Constants The Thomson method utilizes available boiling temperatures at three different pressures to calculate... 

E. DuPont s Process. Some Cordite plants replaced the Thomson method with the "DuPont s Mechanical Dipper Process . This method was briefly described under CELLULOSE AND DERIVATIVES in Vol 2, p C102-R of this Encycl. 

Finishing wood cellulose Other sources of cellulose Drying cellulose before nitration Industrial nitration of cellulose Mixed acids Nitration m pots Centrifugal nitration Thomsons method Nitration with mechanical stirring German method Continuous methods of nitration Literature... 

Consequently, in order for the Joule-Thomson method to function as a liquefaction process, one must operate at a temperature below Tf and... 

R. A. M. Thomson, Methods of polymerization for preparation of water soluble polymer, in Chemistr) and Technology for Water Soluble Polymer, 31-70, C. A. Finch, Ed., Plenum, New York (1983). 

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