NMR determination of high temperature acetic acid/water vapor phase equilibria

AIChE Journal ◽  
2005 ◽  
Vol 52 (1) ◽  
pp. 422-424 ◽  
Author(s):  
Michael J. Richardson ◽  
James H. Johnston ◽  
Peter T. Northcote
Keyword(s):  
Acetic Acid ◽  
Water Vapor ◽  
High Temperature ◽  
Phase Equilibria ◽  
Vapor Phase ◽  
Acid Water ◽  
Acetic Acid Water

Reverse Phase Liquid Chromatographic Determination of Some Food Additives

1987 ◽  
Vol 70 (3) ◽  
pp. 578-582 ◽  
Author(s):  
Madduri Veerabhadrarao ◽  
Mandayam S Narayan ◽  
Omprakash Kapur ◽  
Chilukuri Suryaprakasa Sastry
Keyword(s):  
Acetic Acid ◽  
Benzoic Acid ◽  
Mobile Phase ◽  
Direct Method ◽  
Food Additives ◽  
Acid Water ◽  
Relative Standard ◽  
Acetic Acid Water ◽  
Liquid Chromatographic

Abstract Liquid chromatographic methods are described for the separation and determination of non-nutritive sweeteners, namely, acesulfame, aspartame, saccharin, and dulcin; preservatives such as benzoic acid and p-hydroxybenzoic acid; and caffeine and vanillin in ready-toserve beverages, ice candy, ice cream, squash beverage, tomato sauce, and dry beverage mix samples. These additives are separated on a ^Bondapak C18 column using methanol-acetic acid-water (20 + 5 + 75) as mobile phase and detected by UV absorption at 254 nm. Caffeine, vanillin, dulcin, and benzoic acid can be analyzed quickly by using a mobile phase of methanol-acetic acid-water (35 + 5 + 60). Aspartame can be separated in the presence of caffeine and vanillin by using the mobile phase pH 3 acetate buffer-methanol (95 + 5). Retention factors and minimum detectable limits are described. The percentage error and the percent relative standard deviation for 6 replicate samples ranged from 0.3 to 2.8 and from 1.64 to 3.60, respectively. Recovery of additives added to the foods named and analyzed by the direct method and by extraction ranged from 98.0 to 100.6% and from 91.6 to 101.8%, respectively. The proposed LC techniques are simple, rapid, and advantageous because all the additives can be detected in a single step, which makes it useful for the routine analysis of various food products.

VAPOR–LIQUID EQUILIBRIA, DENSITIES, AND REFRACTIVITIES IN THE SYSTEM ACETIC ACID – CHLOROFORM – WATER AT 25 °C

1963 ◽  
Vol 41 (2) ◽  
pp. 407-429 ◽  
Author(s):  
A. N. Campbell ◽  
E. M. Kartzmark ◽  
J. M. T. M. Gieskes
Keyword(s):  
Acetic Acid ◽  
Molar Volume ◽  
Vapor Phase ◽  
Excess Molar Volume ◽  
Binary Systems ◽  
Acid Water ◽  
Positive Deviation ◽  
Acetic Acid Water ◽  
Vapor Liquid Equilibria ◽  
Vapor Liquid

The volume changes on mixing of the two binary mixtures acetic acid – water and acetic acid – chloroform and of the ternary mixture acetic acid – chloroform – water have been determined. In the system acetic acid – water a volume contraction occurs, showing a minimum excess molar volume at 50 mole%. Partial molal volume determinations suggest the formation of a mixed association of one molecule of water with one molecule of acetic acid. In the system acetic acid – chloroform the excess molar volume function is positive over the complete concentration range and this suggests the probability of a positive deviation from Raoult's law.The refractivities of the two binary systems show that the true molecular volumes of acetic acid, water, and chloroform are additive on mixing.Studies of the vapor–liquid equilibria show that in all three constituent binary systems there is positive deviation from Raoult's law but if the dimerization of acetic acid in the vapor phase is taken into account the vapor pressure behavior of the system acetic acid – chloroform is virtually ideal. The vapor pressures in the ternary system show strong positive deviations from Raoult's law over the complete concentration range. This shows that the line of pseudo-ideality in terms of zero excess molar volume does not really represent ideal behavior. Zero excess molar volume is caused by the counteracting effects of water and of chloroform molecules on acetic acid molecules.In the two binary systems investigated the experimental data satisfy the Gibbs–Duhem–Margules equation. This proves that treatment for dimerization of acetic acid in the vapor phase is not merely permissible but necessary.

Phase equilibria for reactive distillation of diethyl succinate. Part II: Systems diethyl succinate+ethyl acetate+water and diethyl succinate+acetic acid+water

2010 ◽  
Vol 290 (1-2) ◽  
pp. 68-74 ◽  
Author(s):  
Alvaro Orjuela ◽  
Abraham J. Yanez ◽  
Peter K. Rossman ◽  
Dung T. Vu ◽  
Damien Bernard-Brunel ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Phase Equilibria ◽  
Ethyl Acetate ◽  
Reactive Distillation ◽  
Acid Water ◽  
Diethyl Succinate ◽  
Acetic Acid Water
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