Some Physical Chemical Studies with Heteropoly Acids.

1955 ◽  
Vol 59 (10) ◽  
pp. 1074-1076 ◽  
Author(s):  
Melvin C. Baker ◽  
Philip A. Lyons ◽  
S. J. Singer
Keyword(s):  
Heteropoly Acids ◽  
Physical Chemical ◽  
Chemical Studies

scholarly journals PHYSICAL CHEMICAL STUDIES OF THE SURFACTANT DILAURYLDIMETHYLAMMONIUM BROMIDE (DLDMAB): AGGREGATION AND CATALYTIC PROPERTIES

2009 ◽  
Vol 17 (17) ◽  
pp. 21-32
Author(s):  
Elizabeth Fatima de Souza ◽  
Silvia Dani ◽  
Lavinel G. IONESCU
Keyword(s):  
Thermodynamic Parameters ◽  
Catalytic Properties ◽  
Activation Parameters ◽  
Critical Micellar Concentration ◽  
Physical Chemical ◽  
Chemical Studies ◽  
Diphenyl Phosphate ◽  
C 32 ◽  
Free Energy Of Micellization ◽  
Hydrolysis Of

The micellization of dilauryldimethylammonium bromide (DLDMAB) in water was studied by using surface tension measurements. The critical micellar concentration (CMC) was determined at 25°C, 32°C and 40°C and thermodynamic parameters such as the free energy of micellization (∆G°mic), enthalpy (∆H°mic), and entropy (∆S°mic) of micellization were measured. The CMC at 25°C was 4.93 x 10-5 M and the corresponding values of the thermodynamic parameters were: ∆G°mic = -5.87 kcal/mol; ∆H°mic = -1.12 kcal/mol and ∆S°mic = +16.00 e.u. Micelles of the surfactant DLDMAB act as catalysts for the alkaline hydrolysis of p-nitrophenyl diphenyl phosphate (NPDPP) with a maximum catalytic factor of approximately 120 compared to 80 for CTAB. Typical activation parameters measured for 1.00 x 10-3 M surfactant and 0.005 M NaOH were: Ea = 9.7 kcal/mo/; ∆H°≠ = 9.1 kcal/mol; ∆G°≠ = 19.6 kcal/mol and ∆S°≠ = -33.9 e.u. The kinetic results were also analyzed in terms of the pseudo-phase ion-exchange models (PPIE) and showed that the model is applicable to describe the experimental results.

Physical chemical studies of short-chain lecithin homologues. I.

1974 ◽  
Vol 1 (3) ◽  
pp. 175-183 ◽  
Author(s):  
R.J.M. Tausk ◽  
J. Karmiggelt ◽  
C. Oudshoorn ◽  
J.Th.G. Overbeek
Keyword(s):  
Short Chain ◽  
Physical Chemical ◽  
Chemical Studies

scholarly journals PHYSICAL CHEMICAL STUDIES ON THE SPECIFIC INTERACTION OF AN ACRIFLAVINE-PHOSPHOTUNGSTIC ACID COMPLEX WITH DOUBLE-STRANDED NUCLEIC ACIDS

1970 ◽  
Vol 47 (2) ◽  
pp. 500-511 ◽  
Author(s):  
Charles T. Ladoulis ◽  
Thomas J. Gill
Keyword(s):  
Organic Cation ◽  
Phosphotungstic Acid ◽  
Physiological Activity ◽  
Specific Interaction ◽  
Genetic Material ◽  
Acid Complex ◽  
Dna And Rna ◽  
Physical Chemical ◽  
Chemical Studies ◽  
Definition Of

The detailed definition of the structure of DNA in chromosomes and in interphase chromatin is important for correlating the structure of the genetic material with various states of physiological activity. A general approach to developing specific reagents for a variety of such studies in solution and in tissues is to combine a chemically specific organic cation with the electron-opaque phosphotungstic acid (PTA) molecule. The reagent described in this paper was made from the interaction of acriflavine and phosphotungstic acid. The acriflavine-PTA complex (a) displays some unique absorption and fluorescence properties, (b) binds specifically to DNA and RNA by intercalation of the acriflavine moiety, and (c) is electron opaque. In addition, it binds to double-stranded synthetic polynucleotides, but not to a variety of proteins, nucleoproteins, or polysaccharides.

Comparative physical-chemical studies of mammalian arginases

1970 ◽  
Vol 37 (3) ◽  
pp. 345-359 ◽  
Author(s):  
Helga Hirsch-Kolb ◽  
John P Heine ◽  
Helmut J Kolb ◽  
David M Greenberg
Keyword(s):  
Physical Chemical ◽  
Chemical Studies

Effects of ionising radiation on aromatic polymers—Dielectric and other physical/chemical studies

1996 ◽  
Vol 48 (1) ◽  
pp. 120-121 ◽  
Author(s):  
H.M. Li ◽  
R.A. Fouracre ◽  
D.J. Tedford ◽  
S. Wysocki ◽  
S. Karolczak
Keyword(s):  
Ionising Radiation ◽  
Physical Chemical ◽  
Aromatic Polymers ◽  
Chemical Studies
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