Correlation between Macroscopic Diffusion Rates and Microscopic Interactions in Ethylene Glycol-Based Solvents

Author(s):  
Ryo Nagumo ◽  
Kohei Omori ◽  
Yukihiro Muraki ◽  
Shuichi Iwata ◽  
Hideki Mori ◽  
...  
1962 ◽  
Vol 46 (2) ◽  
pp. 245-255 ◽  
Author(s):  
Raimundo Villegas ◽  
Carlo Caputo ◽  
Leopoldo Villegas

The squid nerve barriers are formed by (a) the axolemma (membrane of the axon proper), a membrane 80 Å thick perforated by cylindrical pores 4.0 to 4.5 Å radius, and (b) the Schwann layer, constituted of numerous cells forming a layer one cell thick, crossed by 60 Å wide slit channels. If a molecule present in the axoplasm has to reach the extraneural space, it has to pass (a) the pores, and (b) the channels, in series, and the diffusion rate will depend on the effective diffusion areas per unit path length, Apd/Δx for the axolemma, and Acd/Δx for the Schwann layer. By addition, And/Δx, the transneural effective area for diffusion per unit path length is obtained. The diffusion rates of C14-ethylene glycol (2.2 Å radius), and C14-glycerol (2.8 Å radius) were measured. The diffusion rate of H3-labeled water (1.5 Å radius) has been previously determined. The results expressed in terms of And/Δx (mean values ± SD, referred to 1 cm2 of nerve surface) are 5.3 ± 1.4 cm for water, 2.5 ± 0.4 cm for ethylene glycol, and 0.29 ± 0.03 cm for glycerol. Theoretical values for And/Δx of 2.5 and 0.83 cm for ethylene glycol and glycerol have been calculated. The agreement between the theoretical values for And/Δx and the experimental ones supports the diffusion barrier model described above.


2019 ◽  
Vol 10 (10) ◽  
Author(s):  
Anton Bonartsev ◽  
Vera Voinova ◽  
Elizaveta Akoulina ◽  
Andrey Dudun ◽  
Irina Zharkova ◽  
...  

2020 ◽  
pp. 48-55
Author(s):  
M.E. Sharanda ◽  
◽  
E.A. Bondarenko ◽  

Ethylene glycol and propylene glycol are important representatives of polyols. On an industrial scale, they are obtained from petrochemical raw materials. Within a decade, significant efforts were made for the producing of polyols from biologically renewable raw materials - carbohydrates. The general trend for carbohydrate hydrogenolysis includes application of liquid-phase process with the use of modified metal-oxide catalysts, at 120-120 ° C and pressure of 3MPa or above. So high pressure is used for the reason to increase hydrogen solubility, and also due to the high partial pressure of low boiling solvents. We supposed that usage of high boiling solvents could allow hydrogenolysis to be performed at the lower pressure. Ethylene glycol and propylene glycol are of particular interest as such kind of solvent since they are both the main products of glucose hydrogenolysis. In this work, the process of hydrogenolysis of glucose and fructose over Cu / MgO-ZrO2 catalyst have been studied at temperature range of 160-200 °C and a pressure of 0.1-0.3 MPa in a flow reactor. The solvents were simultaneously the target products of the reaction - ethylene glycol and / or propylene glycol. Gas chromatography and 13C NMR were used for the reaction products identification. It was found that the solubility of glucose in propylene glycol is 21 % by weight, and in ethylene glycol 62% by weight. It was pointed out that the process of hydrogenolysis can take place at a pressure close to atmospheric. Under these conditions, the conversion of hexoses reaches 96-100 %. The reaction products are preferably propylene glycol and ethylene glycol. The total selectivity for C3-2 polyols is 90-94 %, that is higher than in the hydrogenolysis of glucose in aqueous solution.


Author(s):  
Michael A. Henry ◽  
John F. Maddox ◽  
Sushil Bhavnani ◽  
Roy W. Knight ◽  
James Pool

2017 ◽  
Vol 59 (02) ◽  
pp. 10-13
Author(s):  
Trong Tam Nguyen ◽  
◽  
Hung Thang Bui ◽  
Ngoc Minh Phan ◽  
◽  
...  

Sign in / Sign up

Export Citation Format

Share Document