Methanol-poly system

Similar to anhydride-bearing polymers, the synthesis of a poly(norborn-2-en-5-yl-methanol)-derived system, polymerized by a Gmbbs catalyst after scavenging excess of reagent, was reported by Hanson (Tab. 8.3) [42, 43]. 

Fig. 14. ORD and CD of poly-(—)-l 2-diaminopropane sebacamide (XXII) at polymer concentration Cm in CaClj-methanol solvent systems at salt concentration Cgi...

To show how this system works, let us consider some of the values shown in Table 5.1. Firstly, let us use poly(ethylene) as an example. This polymer has a 5p value of 16.2 J cm hexane, with a value of 8 = 14.8 J cm gives a (5. - 5p) of -1.4 J cm, which being less than 4.0 indicates solubility. By contrast, methanol has a 4 value of 29.7 J cm , giving a (4 8p) of 13.5 J cm this indicates that poly(ethylene) is not soluble in methanol. 

Klooster, N. Th. M., van der Trouw, F. Mandel, M. (1984). Solvent effects in polyelectrolyte solutions. 3. Spectrophotometric results with (partially) neutralised poly(acrylic acid) in methanol and general conclusions regarding these systems. Macromolecules, 17, 2087-93. 

Simultaneous determination of both cations and anions in acid rain has been achieved using a portable conductimetric ion-exclusion cation-exchange chromatographic analyzer.14 This system utilized the poly(meth-ylmethacrylate)-based weak acid cation exchange resin TSK-Gel OA-PAK-A, (Tosoh , Tokyo, Japan) with an eluent of tartaric acid-methanol-water. All of the desired species, 3 anions and 5 cations, were separated in less than 30 minutes detection limits were on the order of 10 ppb. Simultaneous determination of nitrate, phosphate, and ammonium ions in wastewater has been reported utilizing isocratic IEC followed by sequential flow injection analysis.9 The ammonium cations were detected by colorimetry, while the anions were measured by conductivity. These determinations could be done with a single injection and the run time was under 9 minutes. 

We have reported the first example of a ring-opening metathesis polymerization in C02 [144,145]. In this work, bicyclo[2.2.1]hept-2-ene (norbornene) was polymerized in C02 and C02/methanol mixtures using a Ru(H20)6(tos)2 initiator (see Scheme 6). These reactions were carried out at 65 °C and pressure was varied from 60 to 345 bar they resulted in poly(norbornene) with similar conversions and molecular weights as those obtained in other solvent systems. JH NMR spectroscopy of the poly(norbornene) showed that the product from a polymerization in pure methanol had the same structure as the product from the polymerization in pure C02. More interestingly, it was shown that the cis/trans ratio of the polymer microstructure can be controlled by the addition of a methanol cosolvent to the polymerization medium (see Fig. 12). The poly(norbornene) prepared in pure methanol or in methanol/C02 mixtures had a very high trans-vinylene content, while the polymer prepared in pure C02 had very high ds-vinylene content. These results can be explained by the solvent effects on relative populations of the two different possible metal... 

Equimolar quantities of 2,4-diamino-l,5-benzenediol dihydrochloride and isophthalic acid were mixed in fresh poly (phosphoric acid) using a high-shear stirrer under a slow stream of nitrogen gas. The system was heated at 40°C for 6 hours, at CG°C for 18 hours, at 120°C for 6 hours, at 160°C for 8 hours, and at 220°C for 24 hours. The resultant mixture was dark brown. The polymer was precipitated from water. After filtration and washing with water and methanol, the solid product was then dissolved in methane-sulfonic acid, filtered and precipitated by the addition of methanol. The solid was washed with concentrated ammonium hydroxide, water, methanol, methanol/benzene mixtures (with a volume ratio of 1/1), and finally benzene. The final product was dark brown. 

Syntheses. The polymerization reaction of poly(2-methyl pentene-1 sulfone) (PMPS) was carried out at -78°C. Purified 2-methyl pentene-1 (42 grams) and condensed SO, (about 125 grams) at a molar ratio of 1 to 4 were charged into the reaction system under atmospheric pressure, and the reaction was Initiated by 2 milliliters of butyl hydroperoxide. The white polymer mass was purified by dissolving 1n acetone, then precipitating Into methanol (8). 

A mechanistic study by Haynes et al. demonstrated that the same basic reaction cycle operates for rhodium-catalysed methanol carbonylation in both homogeneous and supported systems [59]. The catalytically active complex [Rh(CO)2l2] was supported on an ion exchange resin based on poly(4-vinylpyridine-co-styrene-co-divinylbenzene) in which the pendant pyridyl groups had been quaternised by reaction with Mel. Heterogenisation of the Rh(I) complex was achieved by reaction of the quaternised polymer with the dimer, [Rh(CO)2l]2 (Scheme 11). Infrared spectroscopy revealed i (CO) bands for the supported [Rh(CO)2l2] anions at frequencies very similar to those observed in solution spectra. The structure of the supported complex was confirmed by EXAFS measurements, which revealed a square planar geometry comparable to that found in solution and the solid state. The first X-ray crystal structures of salts of [Rh(CO)2l2]" were also reported in this study. 

Ester synthesis of fatty acid ethyl ester. The lipase-catalyzed esterification of fatty acid and alcohol is well-known. It was also favorable for the esterification of poly unsaturated fatty acids under mild conditions with the enzyme. However, the activity of native lipase is lower in polar organic solvents, i.e. ethanol and methanol. The synthesis of Ae fatty acid ethyl ester was carried out in ethanol using the palmitic acid-modified lipase. As shown in Figure 7, the reactivity of the modified lipase in this system was much higher than that of the unmoditied lipase. 

Suppose AHr and ASR are both negative. In this case ASR opposes aggregation while AHr favors it. Since the resistance to aggregation decreases with decreasing temperature, aggregation is expected as T is lowered. Poly(12-hydroxystearic acid) adsorbed from n-heptane and polyoxyethylene adsorbed from methanol are examples of systems that display a CFT with decreasing temperature. Since ASR is the source of the stabilization in these cases, this mechanism is called entropic stabilization. 

Poly(styrene-co-acrylonitrile) samples (SAN) have been fractionated through methanol-acetone or methanol-dichloromethane mixtures of stepwise-altered composition 108) through methanol/dichloromethane, n-hexane/dichloromethane, or methanol/acetone gradients109), cyclohexane/methyl ethyl ketone gradients 110), or (toluene — 1-propanol 50 50)/dimethyl formamide gradients111. Mixtures of ethylene cyanohydrin — ethylene carbonate 112) or cyclohexane — methyl ethyl ketone 113 have also been used for the separation of SAN copolymers. Both the latter systems as well as the n-hexane/dichloromethane gradient109) had the efficacy of fractionating SAN copolymers by composition. 

Reaction of cw- 1,4-Poly butadiene and PVC. Et2AlClt-Cobalt Compound Catalyst. Commercial cw-1,4-polybutadiene prepared with a Et AlCl-cobalt compound catalyst system was freed of antioxidant by solution in benzene and precipitation with methanol. The cis-1,4,polybutadiene had an intrinsic viscosity in benzene at 25 °C of 2.4 and a greater than 96% cis-1,4 content. 

Et2AlCl Catalyst. Under the same conditions as above 20 grams of PVC and 2 grams of cis-1,4-polybutadiene, prepared with an alkyl-aluminum-titanium tetraiodide catalyst system (95% cis-1,4 content, intrinsic viscosity at 25°C in benzene 2.2) in 200 ml chlorobenzene were allowed to react in the presence of 2 mmoles of Et2AlCl at 5°-10°C for 60 minutes. The reaction product was isolated by precipitation in methanol and dried to yield 22.0 grams of modified poly (vinyl chloride). Hexane extraction under reflux for 24 hours removed 8% of hexane-soluble material. 

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