Solvents 2-pyrrolidone

When the copoly condensation is carried out in the melt, very often phase segregation takes place between the oligomer and the precursors of the other block, which may result in quite heterogeneous copolymers. This difficulty can be overcome in different ways. Caymans et al. [16] carried out a pre-polycondensation in a solvent (pyrrolidone) which resulted in a homogeneous mixture of... 

N-methyl-2-pyrrolidone Biodegradable solvent particularly for resins. 

It has been demonstrated that a solvent-extraction procedure with N-methyl pyrrolidone is capable of producing coal-derived extract pitches with low-ash contents. Moreover, the properties of the pitches can be varied by partial hydrogenation of the coal prior to extraction. The yield of the pitches along with the physical and chemical properties of the cokes and graphites vai in an understandable fashion. 

Another type of detergent is a group called the pyrrolidones. These are complex molecules that dissolve in both water and organic solvents. 

Aprotic polar solvents have to be used for several reasons. They are often good solvents for both monomers (including phenolates) and amorphous polymers. In addition, they can also stabilize the Meisenheimer intermediates. Common aprotic polar solvents, such as DMSO, /V,/V-dimcthyl acetamide (DMAc), DMF, N-methyl pyrrolidone (NMP), and cyclohexylpyrrolidone (CHP) can be used. Under some circumstances, very high reaction temperature and boiling point solvents such as sulfolane and diphenyl sulfone (DPS) have to be used due to the poor reactivity of the monomers or poor solubility of the resulting, possibly semicrystalline polymers, as in the PEEK systems. 

Poly(ether ether ketone), known as PEEK, is a crystalline high-temperature thermoplastic. It is produced by a step (condensation) process (see Chapter 2) in which 4,4-difluorobenzophenone is reacted with the anion of hydro-quinone. This reaction is carried out in a high boiling point polar solvent, such as A -cyclohexyl-2-pyrrolidone (1.13). 

This study involved the preparation and characterization of poly(N-phenyl 3,4-dimethylenepyrrolidine) and the subsequent oxidation and reduction of this polymer. The parent polymer was not very soluble, so it was difficult to characterize. However, after oxidizing in the presence of palladium on carbon in nitrobenzene, the resultant poly(N-phenyl 3,4-dimethylenepyrrole) was soluble in several organic solvents. Attempts to reduce the original polymer to the pyrrolidone were unsuccessful. 

Pyrrolidones fit well into the bio-refinery concept since they may be produced in a scheme beginning with the fermentation of a portion of the bio-refineiy s sugar product into succinate. Pyrrolidones are a class of industrially important chemicals with a variety of uses including polymer intermediates, cleaners, and green solvents which can replace hazardous chlorinated compounds. 

The electrodes for examination were produced by smearing of suspension of active materials in the solution of binding substance -po 1 yviny 1 idcncfluoride (PVDF) - on the metal substrate by means of applicator "Doctor Blade" by Hohsen Corp. N-methyl-2-pyrrolidone was used as the solvent for the binding substance. 

The electrode active masses were prepared by mixing the active material with 10 wt.% of polyvynilidene fluoride slurred in 1-methyl-pyrrolidone solvent. The actual mass was then pasted onto one side of precleaned Co foil, dried for 4 h at 100°C, pressed and the disks of 15,6 mm diameter were cut and placed into the cell s coins. Large excess of Li metal (foil) was used as a counter electrode. 1M LiPF6 solution in mixture of ethylene carbonate (50 vol.%) and methyl carbonate was used as an electrolyte (Merck product LP30). 

For example, many microwave-assisted solid-phase coupling reactions utilize l-methyl-2-pyrrolidone (NMP) or 1,2-dichlorobenzene (DCB) as the reaction solvent. The main reason for this is the high thermal stabilities of these solvents and their... 

As far as polymer supports for microwave-assisted SPOS are concerned, the use of cross-linked macroporous or microporous polystyrene (PS) resins has been most prevalent. In contrast to common belief, which states that the use of polystyrene resins limits reaction conditions to temperatures below 130 °C [14], it has been shown that these resins can withstand microwave irradiation for short periods of time, such as 20-30 min, even at 200 °C in solvents such as l-methyl-2-pyrrolidone or 1,2-dichlorobenzene [15]. Standard polystyrene Merrifield resin shows thermal stability up to 220 °C without any degradation of the macromolecular structure of the polymer backbone, which allows reactions to be performed even at significantly elevated temperatures. 

Figures 3 and 4 give displacement isotherms of PVP adsorbed on pyrogenic silica. The polymer surface excess is plotted versus the volume fraction of displacer < >d. Results in Figure 3 are for water as the solvent and in Figure 4 for dioxane as the solvent. Various displacers were used, as indicated in the figures. One of the displacers was N-ethyl pyrrolidone (NEP), which can be considered as the monomer of PVP. From the isotherm in dioxane, it was found that In = 0.14. The aqueous system shows strong...

The three component condensations of aldehydes, amines and elemental sulfur using 1-methyl-2-pyrrolidone as solvent employing microwave flash heating 100-180 °C for 2-20 min give the corresponding primary, secondary and tertiary thioamides (Scheme 6).23... 

Mujazaki et al. [733] found that di-isobutyl ketone is an excellent solvent for the extraction of the 2,4-pyrrolidone dithiocarbamate chelates of these elements from seawater. 

In recent years researchers at West Virginia University have developed coal-derived pitches on a laboratory scale in quantities sufficient to make 1 kg samples of calcined coke for fashioning graphite test specimens. The pitches were derived by utilizing solvent extraction with N-methyl pyrrolidone (NMP). This solvent is able to isolate coal-based pitches m high yield and with low mineral matter content [13]. It is this work that will form the basis of the discussion for the later part of this chapter. 

EXOL N Also called EXOL N Extraction. A solvent extraction process for purifying feedstocks for making lubricating oil. The solvent is N-methyl pyrrolidone. Developed and licensed by Exxon Research Engineering Compary. Seventeen units had been installed by 1994. 

Lai, M.C., Hageman, M.J., Schowen, R.L., Borchardt, R.T., Laiard, B.B., and Topp, E.M. 1999b. Chemical stability of peptides in polymers. 2. Discriminating between solvent and plasticizing effects of water on peptide demidation in poly(vinyl pyrrolidone). J. Pharm. Sci. 88, 1081-1089. 

For the addition of ethylene, EtOAc as solvent was particularly advantageous and gave 418 in 60% yield (Scheme 6.86). The monosubstituted ethylenes 1-hexene, vinylcyclohexane, allyltrimethylsilane, allyl alcohol, ethyl vinyl ether, vinyl acetate and N-vinyl-2-pyrrolidone furnished [2 + 2]-cycloadducts of the type 419 in yields of 54—100%. Mixtures of [2 + 2]-cycloadducts of the types 419 and 420 were formed with vinylcyclopropane, styrene and derivatives substituted at the phenyl group, acrylonitrile, methyl acrylate and phenyl vinyl thioether (yields of 56-76%), in which the diastereomers 419 predominated up to a ratio of 2.5 1 except in the case of the styrenes, where this ratio was 1 1. The Hammett p value for the addition of the styrenes to 417 turned out to be -0.54, suggesting that there is little charge separation in the transition state [155]. In the case of 6, the p value was determined as +0.79 (see Section 6.3.1) and indicates a slight polarization in the opposite direction. This astounding variety of substrates for 417 is contrasted by only a few monosubstituted ethylenes whose addition products with 417 could not be observed or were formed in only small amounts phenyl vinyl ether, vinyl bromide, (perfluorobutyl)-ethylene, phenyl vinyl sulfoxide and sulfone, methyl vinyl ketone and the vinylpyri-dines. 

The heteroatoms S, O, and N can be introduced as substituents of the cluster under acidic conditions (see Scheme 2.2-19). For S and O, the reaction of the hydrochlorides of thiopyrrolidone or pyrrolidone, with the non-protonated form of the pyrrolidone as solvent, is the method used by most workers. The amino group can be introduced with hydroxylamine O-sulfonic acid. 

For this reason pyrrolidones were tested as semi-polar solvents in further experiments [25] and ethylene carbonate (EC) and butylene carbonate (BC) were examined as the polar catalyst phase instead of PC. 

Table 10 Hydroformylation of trans-4-octene in cyclic carbonate/N-octyl-2-pyrrolidone/ extraction agent, T = 125 °C, p(syngas, 1 1) = 10bar, t(reaction) = 4h, m(solvents) = 30 g, n([Rh(acac)(CO)2]) = lO- mol, n(BIPHEPHOS) = 5 x mol...

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