ANALYSIS OF SMALL QUANTITIES OF VOLATILE MATERIAL BY DETERMINATION OF THE VAPOR PRESSURE AND MOLECULAR WEIGHT DURING DISTILLATION

1932 ◽  
Vol 54 (10) ◽  
pp. 3962-3969
Author(s):  
B. G. Šimek ◽  
R. Kassler
Keyword(s):  
Molecular Weight ◽  
Vapor Pressure ◽  
Volatile Material

MOLECULAR WEIGHTS FROM MICRO QUANTITIES OF MATERIALS

1949 ◽  
Vol 27b (3) ◽  
pp. 151-157 ◽  
Author(s):  
I. E. Puddington
Keyword(s):  
Molecular Weight ◽  
Vapor Pressure ◽  
Chemical Compounds ◽  
Unknown Compound ◽  
Molecular Weights ◽  
Pure Solvent ◽  
Unknown Substance ◽  
The Difference

A method is proposed for the determination of the molecular weight of chemical compounds in which the unknown substance may be used successfully m quantities of 1 mgm. or less. The method depends on the accurate measurement of the difference in vapor pressure between a solution of the unknown compound and the pure solvent, and this is accomplished with a modified mercury U-tube manometer. The results presented indicate that the difference between the experimental and theoretical molecular weights is of the order of 2%. Determinations require from two to three hours and the sample may be recovered.

scholarly journals THE DETERMINATION OF MOLECULAR WEIGHT

1955 ◽  
Vol 33 (5) ◽  
pp. 755-762 ◽  
Author(s):  
A. F. Sirianni ◽  
I. E. Puddington
Keyword(s):  
Molecular Weight ◽  
Vapor Pressure ◽  
Organic Compounds ◽  
Chemical Stability ◽  
Pressure Difference ◽  
Molecular Weight Range ◽  
Vapor Pressure Difference ◽  
Static Measurement ◽  
Molecular Weights

The molecular weights of organic compounds of known constitution have been determined with satisfactory accuracy, using milligram quantities of materials, by a static measurement of the vapor pressure difference between pure solvents and solutions of the compounds. The method may be used over a considerable temperature range. The suitability of solvents is governed by their chemical stability and vapor pressure. Results obtained using compounds in the molecular weight range of 600–1000 are reported.

scholarly journals Determination of Molecular Weight

1966 ◽  
Vol 49 (4) ◽  
pp. 744-749
Author(s):  
C L Ogg
Keyword(s):  
Molecular Weight ◽  
Vapor Pressure ◽  
Initial Study ◽  
Vapor Pressure Osmometry ◽  
Reference Standard ◽  
Isothermal Distillation

Abstract An initial study, in which 23 collaborators participated, was conducted on the determination of molecular weight by the isothermal distillation (vapor pressure osmometry) method. Each used his own method and apparatus to analyze four samples in duplicate; the molecular weight ranged from 123 to 891. Results show that the chief problem is the choice of the correct solvent and reference standard and that the use of bare thermistors is questionable.

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