Device for Control of Still-Head Pressures during Isothermal Distillation

1949 ◽  
Vol 21 (11) ◽  
pp. 1416-1417 ◽  
Author(s):  
H. S. Booth ◽  
R. L. Jarry
Keyword(s):  
Isothermal Distillation

Molecular weight microdetermination by isothermal distillation

1961 ◽  
Vol 26 (8) ◽  
pp. 2073-2075 ◽  
Author(s):  
J. Jonas ◽  
J. Kánský ◽  
O. Knessl
Keyword(s):  
Molecular Weight ◽  
Isothermal Distillation

CUPRIETHYLENEDIAMINE AS A REAGENT FOR HEMICELLULOSE SEPARATION FROM WHEAT STRAW HOLOCELLULOSE

1951 ◽  
Vol 29 (11) ◽  
pp. 974-985
Author(s):  
V. D. Harwood
Keyword(s):  
Molecular Weight ◽  
Vapor Pressure ◽  
Petroleum Ether ◽  
Wheat Straw ◽  
Periodate Oxidation ◽  
Chloroform Solution ◽  
Chemical Compositions ◽  
Distillation Method ◽  
Molecular Weights ◽  
Isothermal Distillation

Wheat straw and wheat straw holocellulose were dispersed in aqueous cupriethylenediamine solutions and fractionated by graded precipitation with acid and alcohol. From the holocellulose a 25.4% recovery of a hemicellulose containing negligible quantities of hexoses was achieved. The corresponding product from wheat straw was contaminated with both lignin and cellulose but a comparison of the chemical compositions of the two hemicelluloses showed that the acid chlorite used for delignification had caused very little hydrolytic action. The acetate of the hemicellulose from holocellulose was fractionated from chloroform solution by the addition of petroleum ether into a series of fractions and subfractions. Analysis of representative fractions from this series led to the conclusion that the hexoses present were not chemically combined with pentosan. Molecular weights were determined by periodate oxidation, the Signer isothermal distillation method, and from the lowering of the vapor pressure of their chloroform solutions and showed that the hemicellulose molecules were relatively small (mol. wt. < 10,000). The decreasing ratio of xylose to arabinose in the fractions of lower molecular weight indicated increasing chain branching.

scholarly journals The mechanism of isothermal distillation in the porous-disk osmometer

1948 ◽  
Vol 195 (1040) ◽  
pp. 97-115 ◽  
Keyword(s):  
Thermal Conduction ◽  
Theoretical Study ◽  
Quantitative Relationship ◽  
Porous Disk ◽  
Molecular Weights ◽  
Experimental Apparatus ◽  
Theoretical Investigations ◽  
Isothermal Distillation ◽  
Thermostat Temperature ◽  
Made In

This paper describes the theoretical investigations which have been made in an effort to clarify several well-established but unexplained observations by previous workers who have carried out experiments by the unusual osmotic-pressure technique known as isothermal distillation. The treatment is essentially thermodynamic, and leads to the derivation of equations which agree with the accumulated experimental evidence while showing how substantial improvements in performance can be achieved by designing the apparatus in accordance with the guidance given by the theoretical study. One of the derived equations stresses the importance of good thermal conduction between the solvent and solution inside the stillhead, while another gives a quantitative relationship between thermostat temperature fluctuations and osmoticpressure errors. A description is then given of the essential features of the experimental apparatus which has been built for the application of these theoretical advances to the measurement of the molecular weights of high polymers.

Isothermal distillation in flow injection analysis

1979 ◽  
Vol 109 (1) ◽  
pp. 45-54 ◽  
Author(s):  
E.A.G. Zagatto ◽  
B.F. Reis ◽  
H. Bergamin F ◽  
F.J. Krug
Keyword(s):  
Flow Injection ◽  
Flow Injection Analysis ◽  
Isothermal Distillation
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