Paper acid decomposition

Decomposition of Metal Chlorides by Acids. Two commercial processes employing the acidic decomposition of metal chlorides are the salt—sulfuric acid process and the Hargreaves process. Although these processes are declining in importance, they are used mainly because of the industrial demand for salt cake [7757-82-6] by the paper (qv) and glass (qv) industries. In the United States, however, Httle HCl is produced this way. 

Gold forms a continuous series of solid solutions with palladium, and there is no evidence for the existence of a miscibility gap. Also, the catalytic properties of the component metals are very different, and for these reasons the Pd-Au alloys have been popular in studies of the electronic factor in catalysis. The well-known paper by Couper and Eley (127) remains the most clearly defined example of a correlation between catalytic activity and the filling of d-band vacancies. The apparent activation energy for the ortho-parahydrogen conversion over Pd-Au wires wras constant on Pd and the Pd-rich alloys, but increased abruptly at 60% Au, at which composition d-band vacancies were considered to be just filled. Subsequently, Eley, with various collaborators, has studied a number of other reactions over the same alloy wires, e.g., formic acid decomposition 128), CO oxidation 129), and N20 decomposition ISO). These results, and the extent to which they support the d-band theory, have been reviewed by Eley (1). We shall confine our attention here to the chemisorption of oxygen and the decomposition of formic acid, winch have been studied on Pd-Au alloy films. 

Session 4 focused on recent advances in the thermochemical copper chloride and calcium bromide cycles. Much of the current research on thermochemical cycles for hydrogen production involves the sulphur cycles (sulphur-iodine, hybrid sulphur), however, these cycles require very high temperatures ( 800-900°C) to drive the acid decomposition step. The interest in the Cu-Cl and Ca-Br cycles is due to the lower peak temperature requirements of these cycles. The peak temperature requirement for the Cu-Cl cycle is about 550°C, which would allow this cycle to be used with lower temperature reactors, such as sodium- or lead-cooled reactors, or possibly supercritical water reactors. Ca-Br requires peak temperatures of about 760°C. Both of these cycles are projected to have good efficiencies, in the range of 40%. Work on Cu-Cl is ongoing in France, Canada and the United States. Work on Ca-Br has been done primarily in Japan and the US, with the more recent work being done in the US at ANL. The papers presented in this session summarised the recent advances in these cycles. 

In 2006, GA participated in a study conducted by the Savannah River National Laboratory (Summers, 2006). The S-I process was coupled to a VHTR with a required helium return temperature near 600°C. To efficiently match temperature requirements with available heat, a design was developed to supply HI decomposition section energy with recovered heat from the sulphuric acid decomposition section. For the purposes of comparison and analysis in this paper, the GA flow sheets will refer to this design, and CEA flow sheets will refer to a design in which helium supplies heat to both acid decomposition sections. CEA uses ProSimPlus for flow sheet analysis, and GA uses Aspen Plus . A previous study (Buckingham, 2008) showed that the two process simulators give similar calculated results when the same unit operations and stream compositions are modelled, although different thermodynamic models are used for the calculations. 

Ginosar, D.M., Glenn, A.W., and Petkovic, L.M., Stability of Sulfuric Acid Decomposition Catalysts for Thermochemical Water Splitting Cycles, paper presented at the AlChE Spring Meeting 2005, Atlanta, 2005. 

Schematic diagram of the strategy for solving the problem of the acid decomposition of paper.

The kinetics of the solvolysis of linalyl p-nitrobenzoate were published in note form 18 years ago, but a full discussion of the reaction, including the mechanism for retention of optical activity in the cyclized products, has now been published as one of the Winstein memorial papers. Another paper on the reaction of linalool with phosphorus pentachloride reports 88 % yield of a ca. 3 1 mixture of geranyl and linalyl chlorides (after 4 h at —10 °C). Acetylation of linalool is notoriously fickle on account of ready rearrangements now a method using t-butyl acetate and sodium methoxide is said to give a 90% yield of the unrearranged acetate. The rearrangements involved in the acid decomposition of the... 

The type of problem solving illustrated by investigation of the acid decomposition of paper is quite typical of that which a practicing chemist confronts daily. The first step in successful problem solving is to identify the... 

It is a liquid, b,p. 363 K, but if heated it decomposes and hence must be distilled under reduced pressure decomposition may occur with explosive violence and this can occur even at room temperature if impurities are present. Combustible material, for example paper and wood, ignite spontaneously with explosive violence on contact with the acid, and it can produce painful blisters on the skin,... 

Dissolve 20 g, (19 -6 ml.) of anihne in a mixture of 55 ml. of concentrated hydrochloric acid (1) and 55 ml. of water contained in a 350 ml, conical flask. Place a thermometer in the solution and immerse the flask in a bath of crushed ice (2) cool until the temperature of the stirred solution falls below 5°, Dissolve 16 g. of sodium nitrite in 75 ml. of water and chUl the solution by immersion in the ice bath add the sodium nitrite solution (3) in small volumes (2-3 ml. at a time) to the cold anihne hydrochloride solution, and keep the latter weh stirred with the thermometer. Heat is evolved by the reaction. The temperature should not be allowed to rise above 10° (add a few grams of ice to the reaction mixture if necessary) otherwise appreciable decomposition of the diazonium compound and of nitrous acid wih occur. Add the last 5 per cent, of the sodium nitrite solution more slowly (say, about 1 ml. at a time) and, after stirring for 3-4 minutes, test a drop of the solution diluted with 3-4 drops of water with potassium iodide - starch paper (4) if no immediate blue colour... 

Amino acids have high melting or decomposition points and are best examined for purity by paper or thin layer chromatography. The spots are developed with ninhydrin. Customary methods for the purification of small quantities of amino acids obtained from natural sources (i.e. l-5g) are ion-exchange chromatography (see Chapter 1). For general treatment of amino acids see Greenstein and Winitz [The Amino Acids, Vols 1-3, J.Wiley Sons, New York 1961] and individual amino acids in Chapters 4 and 6. 

A. l-Formyl-3-thiosemicarbazide. Four hundred milliliters of 90% formic acid contained in a 2-1. round-bottomed flask is heated on a steam bath for 15 minutes, and then 182 g. (2 moles) of colorless thiosemicarbazide (Note 1) is added. The mixture is swirled until the thiosemicarbazide dissolves. The heating is continued for 30 minutes, during which time crystalline 1-formyl-3-thiosemicarbazide usually separates. Boiling water (600 ml.) is added, and the milky solution that results is filtered through a fluted filter paper. After standing for 1 hour, the filtrate is cooled in an ice bath for 2 hours, and the l-formyl-3-thiosemicarbazide that separates is collected by suction filtration and air-dried overnight. It weighs 170 192 g. (71-81%) and melts at 177-178° with decomposition. 

One-tenth mol (20 g) of benzhydryl chloride was mixed with 0.19 mol (19 g) of N-methyl-piperazine and about 10 cc of benzene and the whole was heated on the steam bath four hours. The contents of the flask was partitioned between ether and water, and the ethereal layer was washed with water until the washings were neutral. The base was then extracted from the ethereal layer by N hydrochloric acid and the extract, made acid to Congo red paper, was evaporated under vacuum, 29.5 g of the pure dihydrochloride of N-methyl-N -benzhydryl piperazine was recovered from the residue by recrystallization from 95% alcohol melting above 250°C with decomposition. 

A review of earlier results is included in a paper by Kiyoura and Urano [946] on the decompositions of (NH4)2S04 (413—513 K) and NH4HS04 (433-473 K). The intermediate formation at 433 K of the double salt (NH4)3H(S04)2 was detected by X-ray diffraction and this salt decomposed to NH4HS04 at 453 K. Decomposition of the ammonium hydrogen sulphate at 473 K proceeded through the formation of molten sulphamic acid... 

---