A laboratory experiment on the boiling-point curves of non-azeotropic binary mixtures

1929 ◽  
Vol 6 (9) ◽  
pp. 1544 ◽  
Author(s):  
George W. Bennett
2008 ◽  
Vol 3 (1) ◽  
pp. 52-55
Author(s):  
Gheorghe Zgherea

Mixtures of small quantities of carbonyl compounds are presents in foods, concerning sensorial qualities. The inferior carbonyl compounds (C2-C4, boiling point <100°C) – mono and dicarbonyl – can be identified and measured their concentrations, after a separation by distillation on the water bath. They are transferred in a strongly acid solution of 2.4-dinitrophenylhidrazine (2.4-DNPH), generating a mixture of insoluble 2.4-dinitrophenylhidrazones (2.4-DNPH-ones). The 2.4-DNPH-ones are organic compounds with weak polarity, solids, crystallized, yellows and water insoluble, soluble in organic solvents. The mixture of 2.4dinitrophenylhidrazones may be separated by liquid chromatography, using the reverse phase mechanism [1-3]. This paper contains experimental and theoretical considerations to the means of separation through liquid chromatography of two synthetically and a natural mixtures that contain 2.4-DNPH-ones provided by inferior carbonyl compounds; to obtain conclude results, in the synthetically mixtures was introduce and 2.4-DNPH-ones provided by carbonyl compounds having three (acetone and propanal) and four (isobutyl aldehyde) atoms of carbon.


AIHAJ ◽  
1996 ◽  
Vol 57 (8) ◽  
pp. 717-723 ◽  
Author(s):  
Coreen A. Robbins ◽  
Patrick N. Breysse

1938 ◽  
Vol 11 (2) ◽  
pp. 319-330
Author(s):  
J. M. Wright ◽  
B. L. Davies

Abstract Since Ostromislensky (J. Russ. Phys. Chem. Soc., 49, 1456 (1916)) claimed that vulcanization of rubber in the presence of m-dinitrobenzene entailed the addition of oxygen to the rubber molecule, it has been suggested that this form of vulcanization may be the oxygen analog of ordinary sulfur vulcanization. Blake (Ind. Eng. Chem., 22, 740 (1930)), however, extracted vulcanizates with acetone and determined the nitrogen content. If it were assumed that the unextractable nitrogen was combined with the rubber, the figures indicated that the chemical reaction was monomolecular, and in explanation it was suggested that consecutive reactions occurred, one of which was slow. The vulcanizate was concluded to be an additive compound of the vulcanizing agent with the rubber. Objects and Technic.—The objects of the present work were to answer two questions: (1) what are the reactants, and (2) in what manner do they react? It was hoped with the simplest binary mixtures to find what were the essential ingredients, and to proceed to increasingly complex mixtures to discover the roles of the various accessory substances. By vulcanization in solution it was found that the examination of the final reaction mixture was facilitated. The mixes were therefore dispersed in technical xylene, of boiling point 140° C., and vulcanized by boiling. At a particular stage, the rubber became insoluble, and the time required to arrive at this stage was a characteristic of the mix and was taken to be proportional to the rate of reaction.


2003 ◽  
Vol 190 (2) ◽  
pp. 171-176 ◽  
Author(s):  
T. E. Vittal Prasad ◽  
D. H. L. Prasad ◽  
G. V. Ramserish ◽  
P. Satya Kishore

2006 ◽  
Author(s):  
Daren S. Protolipac ◽  
Lisa Finkelstein ◽  
John Kulas

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