Dimethyl-formamide DMF

Poly(7-benzyl-L-glutamate) is known to possess a helical structure in certain solvents. As part of an investigationf of this molecule, a fractionated sample was examined in chloroform (CHCI3) and chloroform saturated ( 0.5%) with dimethyl formamide (DMF). The following results were obtained ... 

One approach is to uses solvent extraction with dimethyl formamide (DMF) to remove Cj acetylene and a C, acetylene-propadiene mixture from their steam cracked ethylene and propylene streams. The simple acetylene is sold as welding gas, and the C, stream is sold as starting material for chemical synthesis. 

A condensible blowdown tank, designed on a similar basis to that described above for phenol, may be provided in other services where a conventional condensible blowdown drum would not be acceptable (e.g., due to effluent water pollution considerations). Examples of such cases are methyl ethyl ketone (MEK) and dimethyl formamide (DMF). A suitable absorbing material is specified (e.g., a lube oil stock for MEK water for DMF), and the design must include consideration of maximum permissible operating temperatures to prevent excessive vapor evolution or the boiling of water. 

Select mobile phases for HPSEC based on their ability to dissolve the sample and their compatibility with the column. Zorbax PSM columns are compatible with a wide variety of organic and aqueous mobile phases (Table 3.4), but analysts should avoid aqueous mobile phases with a pH greater than 8.5. As mentioned earlier, select mobile phases that minimize adsorption between samples and silica-based packings. Sample elution from the column after the permeation volume indicates that adsorption has occurred. If adsorption is observed or suspected, select a mobile phase that will be more strongly adsorbed onto the silica surface than the sample. For example, N,N-dimethyl-formamide (DMF) is often used for polyurethanes and polyacrylonitrile because it eliminates adsorption and dissolves the polymers. When aqueous mobile phases are required, highly polar macromolecules such as Carbowax can be used to coat the silica surface and eliminate adsorption. Table 3.5 provides a list of recommended mobile-phase conditions for some common polymers. 

Fryer et al. have found that hcnzodiazepinones rearrange to isoindoles in high yield under a variety of conditions. The benzo-diazepinone (73), on treatment vuth sodium hydride in dimethyl formamide (DMF), gave the isoindolecarboxamide (74) in better than... 

Silver nitrate and/or cuppric nitrate [50] can photoinitiate the polymerization of acrylonitrile in a dimethyl formamide (DMF) medium. The photoactive species is the complex formed between the monomer and salt molecules ... 

Polar aprotic solvent (Section 11.3) A polar solvent that can t function as a hydrogen ion donor. Polar aprotic solvents such as dimethyl sulfoxide (DMSO) and dimethyl-formamide (DMF) are particularly useful in Sn2 reactions because of their ability to solvate cations. 

Dimethyl ester-diol polyesterifications, 84 Dimethyl formamide (DMF), 79, 295 Dimethyl isophthalate (DMI), 106 Dimethylol propionic acid (DMPA), 238 Dimethyl sulfoxide (DMSO), 83, 185,... 

The Hg/dimethyl formamide (DMF) interface has been studied by capacitance measurements10,120,294,301,310 in the presence of various tetraalkylammonium and alkali metal perchlorates in the range of temperatures -15 to 40°C. The specific adsorption of (C2H5)4NC104 was found to be negligible.108,109 The properties of the inner layer were analyzed on the basis of a three-state model. The temperature coefficient of the inner-layer potential drop has been found to be negative at Easo, with a minimum at -5.5 fiC cm-2. Thus the entropy of formation of the interface has a maximum at this charge. These data cannot be described... 

Intrinsic Viscosity Measurements were made by standard techniques in dimethyl formamide (DMF) at 30 C. Weight average molecular weights were calculated from the following relationship ... 

Allyl chloride and a-phenylethyl chloride are reduced by Cr(II) sulphate in aqueous dimethyl formamide (DMF) in a simple second-order process. At 29.7... 

The reaction of eq. 16.9 will regenerate the antioxidant Arj-OH at the expense of the antioxidant At2-OH. Despite the fact that such regeneration reactions are not simple electron transfer reactions, the rate of reactions like that of eq. 16.9 has been correlated with the E values for the respective Ar-0. Thermodynamic and kinetic effects have not been clearly separated for such hierarchies, but for a number of flavonoids the following pecking order was established in dimethyl formamid (DMF) by a combination of electrolysis for generating the a-tocopherol and the flavonoid phenoxyl radicals and electron spin resonance (ESR) spectroscopy for detection of these radicals (Jorgensen et al, 1999) ... 

Dimethyl formamide (DMF) has been found to be a particularly useful solvent in these reactions because it absorbs MW irradiation strongly, has a relatively high boil-... 

The protected 5-amino-l-ribofuranosyl-4-(5-methyl-l,2,4-oxadiazol-3-yl)imidazole 58 (Equation 4) undergoes MHR to afford the 3-acetamidoimidazopyrazole 59 in dimethyl formamide (DMF) or DMSO as solvent at... 

Dehydrative condensation of pyrrole-2-carboxaldehyde 77 and ethyl carbazate afforded carbethoxyhydrazone 78 in quantitative yield. Cyclization of 78 in the presence of a catalytic amount of sodium hydride (10mol%) in dimethyl-formamide (DMF) at 100°C led to the formation of pyrrolo[l,2-tf][l,2,4]triazin-4-one 27 in 75% yield (Scheme 8) <1999T13703>. 

The reaction of the -C(Hal)=N-function with azide ion or hydrazoic acid is known to give the tetrazole system. As part of a mechanistic study of the one-pot synthesis of an azadibenzoporphyrine in 84% isolated yield from reaction of a 1-bromobenzopyrromethene hydrobromide 74 with sodium azide at 140 °C, 74 was treated with azide at lower temperature (60 °C) in an attempt to isolate the proposed azide mechanistic intermediate 75 however, the fused tetrazole 76 was isolated in 47% yield (identified by X-ray analysis) (Equation 4) <1999MI530>. Upon heating a dimethyl formamide (DMF) solution of tetrazole 76 to 140°C for 1 h, the desired porphyrin was indeed obtained in 14% yield, consistent with the temperature-dependent equilibrium between tetrazole and azide that has been observed with some fused tetrazoles. 

The hydroboration/oxidation sequence does not change the molecular-weight distribution. Gel permeation chromatography (GPC) measurements in dimethyl-formamide (DMF) with the resulting polystyrene-ft-polyalcohol polymers show very similar polydispersity indexes (Table 10.2). Here, the hydroboration/oxidation sequence is clearly superior to the epoxidation reaction, which leads to a... 

Materials. Reagent grade solvents, dimethyl formamide (DMF), dimethyl acetamide (DMAC), dimethyl sulfoxide (DMSO) and methanol were purchased from Baker, stored over molecular sieves once opened, and used without further purification. Aminoethane thiosulfuric acid (AETSA) purchased from Kodak, and Taurine, purchased from Alfa were purified by recrystallization. Each was thrice recrystallized from hot, deionized water. The crystalline precipitate was dried (48 hours at 40 °C) in-vacuo and subsequently stored in a desiccator. Benzophenone (BP) was purchased from Aldrich Chemical Company. QUANTACURE BTC (BTC), (4-benzolybenzyl) trimethylammonium chloride, was used as supplied by Aceto, Inc., Flushing, New York. Phenyl glycidyl ether (PGE) was purchased from MCB, distilled in-vacuo. and stored at -15 °C. Epon 828 was used as supplied bv Shell Chemical Company. The epoxy equivalent weight (EEW) for Epon 828 determined by an appropriate titration, was found to be 187.7. 

The syntheses of the receptors 10 and 12 were carried out by the treatment of bisphenol porphyrin 13 and its Zn complex 14, respectively, with portionwise addition of a large excess of P-cyclodextrin-6-O-monotosylate (CD-Tos) 15 using caesium carbonate as base in N,N dimethyl formamide (DMF) (Fig. 6) (13). 

A procedure given by Zahn and Wiirz (89) was followed. 0.5 gm of the carbon was agitated with 25 ml of a 1 if solution of DNFB in dimethyl-formamide (DMF) for 20 hours. In order to neutralize the HF set free, 10 ml of a 1% aqueous solution of NaHCOj were added. The reaction products were washed and extracted successively with DMF, dilute HCl, methanol, and ether. Nitrogen determinations, Kjeldahl as well as Dumas determinations, gave identical results. Treatment with p-nitrobenzoylchloride followed standard procedures. 

Melt spinning is not used for polyacrylics because they are sensitive to high temperatures. They actually begin to decompose before they reach melting temperature. Solution spinning is used instead. The dried polymer is dissolved in a polar solvent like acetone or dimethyl formamide (DMF). The spinning mechanics are otherwise the same, except the solvent is recovered as it vaporizes, immediately after the extrusion through the spinneret. Most acrylics are sold and used in the form of staple fiber. 

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