Effect of Lithium tert-Alkoxides on Anionic Polymerization of Butadiene Initiated with a Bifunctional Initiator

2000 ◽  
Vol 65 (3) ◽  
pp. 352-360 ◽  
Author(s):  
Luděk Toman ◽  
Petr Vlček ◽  
Miloslav Sufčák ◽  
Alexander Pleska ◽  
Jiří Spěváček ◽  
...  
Keyword(s):  
Methyl Ether ◽  
Anionic Polymerization ◽  
Polymerization Rate ◽  
Fold Excess ◽  
Butyl Methyl Ether

Polymerization of buta-1,3-diene initiated by bifunctional dilithium initiator in tert-butyl methyl ether, hexane and hexane-toluene mixtures was studied in the presence of Li tert-butoxide, 2-methylpentan-2-olate, 3-methylpentan-3-olate or 2,3-dimethylbutan-2-olate. The alkoxides lower the overall polymerization rate and affect, to a certain extent, microstructure of formed polymers. When applied in a concentration equal to that of the initiating centres, they lower the content of vinyl structures in polybutadiene by 10-12%. Increasing concentration of the alkoxide has no perceptible effect and, if used in 12-fold excess over the initiator, the content of 1,2-structures even increases. Polymers prepared in the presence of an alkoxide mostly have unimodal and narrow MWDs.

Crystal Structures of Two New Cyclosporin Clathrates

2000 ◽  
Vol 65 (12) ◽  
pp. 1950-1958 ◽  
Author(s):  
Michal Hušák ◽  
Bohumil Kratochvíl ◽  
Ivana Císařová ◽  
Alexandr Jegorov
Keyword(s):  
Crystal Structures ◽  
Methyl Ether ◽  
Van Der Waals ◽  
Van Der Waals Interactions ◽  
Solvent Molecules ◽  
Butyl Methyl Ether

Two isomorphous clathrates formed by dihydrocyclosporin A or cyclosporin V with tert-butyl methyl ether are reported and compared with the structures of related P21-symmetry cyclosporin clathrates. The cyclosporin molecules in both structures are associated via van der Waals interactions forming cavities occupied by solvent molecules (cyclosporin : tert-butyl methyl ether is 1 : 2).

Storage Stability of Solvent-Free Condensates of Functionalized Trialkoxysilanes

1999 ◽  
Vol 576 ◽  
Author(s):  
S. Stein ◽  
St. Cramer V. Clausbruch ◽  
N. Moszner ◽  
V. Rheinberger Ivoclar Ag
Keyword(s):  
Methyl Ether ◽  
Storage Stability ◽  
Solvent Free ◽  
Residual Silanol Groups ◽  
Acid Catalyzed ◽  
Chemical Conditions ◽  
Degree Of Condensation ◽  
Hydrolysis Of ◽  
Initial Viscosity ◽  
Butyl Methyl Ether

ABSTRACTThe lack of storage stability of organic-inorganic solvent-free sols is a well-known problem. We investigated the influence of different solvents in the acid catalyzed hydrolysis of various sols on their storage stability. Our experiments were based on two different silanes, 3-methacryloxypropyltrimethoxysilane (MPTS) and 1,1,1-tris(allyloxymethyl)-l-[[[3-(triethoxysilyl)propyl]aminocarbonyl]oxymethyl]methane (silane 31), synthesized by reaction of pentaerythritol triallyl ether and 3-isocyanatopropyltriethoxysilane. The employed solvents were alcohol, tetrahydofuran and tert-butyl methyl ether in a range of 95 wt% to 30 wt% in solution. In order to get comparable chemical conditions the degree of condensation of the various sols were adjusted between 75% and 85%. Furthermore, the sols were modified by silylation with trimethylchlorosilane. A comparison of silylated and not silylated silane 31 clearly showed that a decrease in residual silanol groups increase the storage stability. The results of the investigations demonstrated that both the kind and the amount of solvent used in hydrolysis affects the initial viscosity of solvent-free condensates of silane 31 and MPTS.

Excess volumes for binary mixtures of n-butyl methyl ether with n-alkanes at 298.15 K

1990 ◽  
Vol 35 (3) ◽  
pp. 242-244 ◽  
Author(s):  
Luo Wang ◽  
George C. Benson ◽  
Benjamin C. Y. Lu
Keyword(s):  
Binary Mixtures ◽  
Methyl Ether ◽  
Excess Volumes ◽  
Butyl Methyl Ether

tert-Butyl methyl ether C5H12O + C8H18 2,2,4-Trimethylpentane

2007 ◽  
pp. 1-1
Author(s):  
I. Wichterle ◽  
J. Linek ◽  
Z. Wagner ◽  
J.-C. Fontaine ◽  
K. Sosnkowska-Kehiaian ◽  
...  
Keyword(s):  
Methyl Ether ◽  
Tert Butyl ◽  
Butyl Methyl Ether

tert-Butyl methyl ether C5H12O + C8H18 2,2,4-Trimethylpentane

2007 ◽  
pp. 1-1
Author(s):  
I. Wichterle ◽  
J. Linek ◽  
Z. Wagner ◽  
J.-C. Fontaine ◽  
K. Sosnkowska-Kehiaian ◽  
...  
Keyword(s):  
Methyl Ether ◽  
Tert Butyl ◽  
Butyl Methyl Ether

1-Methylpyrrolidin-2-one C5H9NO + C5H12O tert-Butyl methyl ether

2007 ◽  
pp. 1-1
Author(s):  
I. Wichterle ◽  
J. Linek ◽  
Z. Wagner ◽  
J.-C. Fontaine ◽  
K. Sosnkowska-Kehiaian ◽  
...  
Keyword(s):  
Methyl Ether ◽  
Tert Butyl ◽  
Butyl Methyl Ether

Ethyl propanoate C5H10O2 + C5H12O Butyl methyl ether

2007 ◽  
pp. 1-1
Author(s):  
I. Wichterle ◽  
J. Linek ◽  
Z. Wagner ◽  
J.-C. Fontaine ◽  
K. Sosnkowska-Kehiaian ◽  
...  
Keyword(s):  
Methyl Ether ◽  
Butyl Methyl Ether
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