Diethyl ether flexibility

A quantity of I (0.200 g, 0.412 mmol) is dissolved in 20 mL of acetone in a 100-mL Schlenk flask in the air. After 48 h at room temperature in the air, the deep purple color of the solution fades to a pale brown with precipitation of a crystalline material. The reaction is complete when a TLC (IB2-F flexible sheets, J. T. Baker, CH2C12 as elutant) shows the disappearance of the band due to I (R = 0.3) and the appearance of the band due to II (Rr = 0). The reaction mixture is dried under vacuum. The solid product is washed with 5 mL of diethyl ether and 20 mL of hexane and dried again to give shining black crystals. The total weight of crystals is 0.171 g (0.0541 mmol), corresponding a 96% yield based on total cobalt when optimized. The checkers observed variable and generally lower yields. 

Teflon tubing provides flexibility and does not contain plasticizers to contaminate the final diazomethane/diethyl ether solution. 

Manufacture. Much of the diethyl ether manufactured is obtained as a by-product when ethanol (qv) is produced by the vapor-phase hydration of ethylene (qv) over a supported phosphoric acid catalyst. Such a process has the flexibility to adjust to some extent the relative amounts of ethanol and diethyl ether produced in order to meet existing market demands. Diethyl ether can be prepared directly to greater than 95% yield by the vapor-phase dehydration of ethanol in a fixed-bed reactor using an alumina catalyst (21). 

Another exceedingly important validation step for emphatically flexible molecules is to test whether steric parameters derived by averaging the characteristics of a diverse conformational set are capable of reproducing the flexibility of species from the smdied series at the MD level. Due to the unusual behavior of the torsion angles in this class of compounds (the pronounced gauche-effect), it is necessary to generate the probability distribution of the parametrized dihedral angle C-O-C-C and the symmetric C-C-O-C in the MD simulation of diethyl ether in liquid phase in order to check the performance of the modified force field. 

Li et al. [641] recently showed that high quality P(P) films could be prepared via electropolymerization of benzene at stainless steel electrodes, employing a BF3-diethyl ether medium. Films obtained were said to be flexible and cuttable into any shape. Their conductivity, modulus, and tensile strength were claimed to be, respectively, 2.7 S/cm, 1.2 X 10 ° dyne/cm and 600 kg/cm. ... 

Maleate/vinyl ether formulations based on a model unsaturated polyester prepared from maleic anhydride and 1,5-pentane diol and triethylene glycol divinyl ether were studied. At molecular weights of less than about 10,000 the cured films were extremely brittle. When the equivalent weight of the unsaturated polyester was increased by replacing some of the maleic anhydride with succinic anhydride, measurable values for film elongation could be obtained but the cure speed was definitely slower. When either diethyl maleate or isobutyl vinyl ether were added as monofunctional diluents the cure dose needed to obtain 200 MEKDR was increased and the flexibility measured by pencil hardness increased as the amount of diluent was increased. A urethane vinyl ether was synthesized and used to replace DVE-3 and films with increased elongation were obtained at equivalent at dosages as low as 1 J/cm2. 

---