The extracts were then dried under nitrogen, resuspended with a mixture of acetonitri1e : methanol : tetrahydrofurane
(THF) as the solvent, the extraction time was decreased four-fold while the fraction extracted was increased thrice at room temperature by using ultrasounds under 20 kHz frequency.
Sodium diphenyl amino-4-sulfonate (>99%; Sigma-Aldrich), ammonium persulfate (98%; Sigma-Aldrich), sodium hydroxide (Fluka), sodium sulfate (Merck), hydrochloric acid (37%; Merck), ammonium hydroxide (Sigma-Aldrich), analytical grade ethanol (Merck), tetrahydrofurane
(Merck), and diethyl ether (Merck) were used in synthesis of the polymers.
dimethyl ether, iso-propylether, tetrahydrofurane
, hexane and toluene (Guan et al.
Indeed, the prepared copolymers are insoluble in dichloromethane, ethanol, tetrahydrofurane
but they can dissolve in dimethylformamide.
8), methanol and tetrahydrofurane
as mobile phase (A, 82:17:1; B, 22:77:1) at a flow-rate of 1.
1] solution was prepared by dissolving an appropriate amount in tetrahydrofurane
, Merck (Darmstadt, Germany).
First, oxidative hydroboration of separated exo-benzyllactol exo-7b, with the hydroborane tetrahydrofurane
complex used, afforded a mixture of regio- and diasereoisomeric bicyclic alcohols exo-8b + exo-9b.
At the first step, a mixture of conductive material consisting of 50 % (w/w) graphite, 35 % (w/w) epoxy and 15 % (w/w) hardener was prepared by dissolving in sufficient tetrahydrofurane
n]) were estimated by gel permeation chromatography in tetrahydrofurane
Thermo-optical studies of solutions of asphaltenes in toluene and tetrahydrofurane
 have shown that the solvent molecules can be trapped during aggregation of asphaltenes resulting in minimum diffusivities (D) before 50 mg/l and an increase in D at higher concentrations until a constant value is reached near 2000 mg/l.
The nature of association in tetrahydrofurane
and diethyl ether solutions.