Poly methyl butanes

Fresh rat brain tissue is immediately immersed in 2-methyl butane at -15 to -25°C for several minutes and stored at -70°C. Sections (10 p,m) are cut in the parasagittal plane on a cryostat, which are thaw-mounted onto poly-L-lysine-coated glass slides and stored at -70°C. The sections are dried on a slide warmer at the lowest setting to avoid excessive drying. They are fixed with 4% formaldehyde in PBS (pH 7.5) for 30 min and then rinsed three times for 10 min each in PBS to remove excess fixative. This is followed by treatment with 0.3% hydrogen peroxide in PBS for 30-40 min to quench endogenous peroxidase activity. 

By using an imidazolium ionic liquid with a chiral alkyl chain, R-(+)-2-methyl butane, induction of isotactic sequences in the poly(methyl acrylate)... 

The sensitivity of the helical preference of polyisocyanates to small chiral influences is also observed in chiral solvents. Poly(n-hexyl isocyanate) was found experimentally to have a persistence length of 20— 40 nm depending on the solvent in which the measurements were carried out.66 It was hypothesized that in more polar solvents a local interaction of the solvent would give rise to larger torsional oscillations around the backbone bonds. It was indeed observed that dissolution of poly(n-hexyl isocyanate) in non-racemic chiral solvents, e.g., (5)-l-chloro-2-methyl-butane, changed the persistence length and in addition also resulted in an excess of one helical sense.67 The chiral bias favoring one helical sense by itself is miniscule, but due to the cooperativity, a chiral preference is observed. More recently it was noted that the circular dichroism of these polymers decreases upon the addition of an achiral or racemic... 

Fig. 5.6. The dependence of the CFTs (both UCFT and LCFT) upon latex particle concentration for poly(methyl methacrylate) particles stabilized by poly(dimethylsiloxane) dispersion medium 1,2 n-propane 3,4 n-butane 5,6 -pentane (after Everett and Stageman, 1977).

Currently, almost all acetic acid produced commercially comes from acetaldehyde oxidation, methanol or methyl acetate carbonylation, or light hydrocarbon Hquid-phase oxidation. Comparatively small amounts are generated by butane Hquid-phase oxidation, direct ethanol oxidation, and synthesis gas. Large amounts of acetic acid are recycled industrially in the production of cellulose acetate, poly(vinyl alcohol), and aspirin and in a broad array of other... 

Phase behavior studies with poly(ethylene-co-methyl acrylate), poly (ethylene-co-butyl acrylate), poly(ethylene-co-acrylic add), and poly(ethylene-co-methacrylic acid) were performed in the normal alkanes, their olefinic analogs, dimethyl ether, chlorodifluoromethane, and carbon dioxide up to 250 °C and 2,700 bar. The backbone architecture of the copolymers as well as the solvent quality greatly influences the solution behavior in supercritical fluids. The effect of cosolvent was also studied using dimethyl ether and ethanol as cosolvent in butane at varying concentrations of cosolvent, exhibiting that the cosolvent effect diminishes with increasing cosolvent concentrations. 

L = bis(hydroxymethyldihydroxyoxazolyl)pyridine = 1,4-bis(diphenylphosphanyl)butane L = (S,S)-2,6-bis-(4-isopropyl-2-oxazolin-2yl)pyridine PS-PEG = polystyrene-poly(ethyleneglycol) L-abrine = N-(a)-methyl-L-... 

Nagai, K., Sugawara, A., Kazama, S. and Freeman, B.D. 2004. Effects of physical aging on solubility, diffusivity, and permeability of propane and n-butane in poly(4-methyl-2-pentyne). J. Polvm. Sci. B Pol. Phvs. 42(12) 2407-2418. 

Yave, W., Shishatskiy, S., Abetz, V., Matson, S., Litvinova, E., Khotimskiy, V. and Peinemann, K.V. 2007. A novel poly(4-methyl-2-pentyne)/Ti02 hybrid nanocomposite membrane for natural gas conditioning Butane/methane separation. 

Chemical name poly[[6-[(1,1,3,3-tetramethylbutyl) amino]-1,3,5-triazine-2,4-diyl] [(2,2,6,6-tetramethyl-4-piperidinyl) imino]-1,6-hexanediyl[(2,2,6,6-tetra-methyl-4-piperidinyl)imino]]) + butane-dioic acid, dimethylester, polymer with 4-hydroxy-2,2,6,6-tetramethyl-1-piperidine ethanol ... 

Quaternary ammonium ion exchange resins were produced initially by chloromethylating crosslinked polystyrene beads with chloromethyl methyl ether, followed by quaternization with tertiary amines. We have circumvented exposure to the highly carcinogenic bis(chloromethyl) ether, a common contaminant of commercial chloromethyl methyl ether, by employing l,4-bis(chloromethoxy)butane or 1-chloromethoxy-4-chlorobutane and have produced chloromethylated poly(oxy-2,6-dimethyl-1,4-phenylene) and polysulfone. Alternatively, chloromethyl methyl ether can be generated from acetyl chloride and methylal, and the reaction mixture utilized directly in chloromethylation of activated aromatic repeat units. 

Poly(4-methyl-2-pentyne) [PMP] is a glassy, disubstituted, purely hydrocarbon-based polyacetylene. PMP has a density of only 0.78 g/cm and a high fractional free volume of 0.28. The polymer has very high hydrocarbon permeabilities for example, the /i-butane permeability of PMP in a mixture of 2 mol% n-butane in methane is 7,500 X lO l cm3(STP) cm/cm2 s cmHg at 25 C. In contrast to conventional, low-free-volume glassy polymer membranes, PMP is significantly more permeable to n-butane than to methane in gas mixtures. In this paper, we present the gas permeation properties of PMP in mixtures of -butane with methane. The mixed-gas permeation and physical aging properties of PMP are compared to those of poly(l-trimethylsilyl-l-propyne), the most permeable polymer known. 

Figure 2. Mixed-gas methane and w-butane permeability of poly(4-methyl-2-pentyne) as a function of -butane relative pressure. Feed 2 mol% n-butane in methane feed pressure 150 psig permeate pressure atmospheric (0 psig) T=25°C.

Nanocomposite membranes based on poly(4-methyl-2-pentyne) (PMP) and nano-sized fumed silica fillers have been put forward as a possible alternative to the less chemically resistant PTMSP for the removal ofC hydrocarbons (He et al, 2002). Specifically, an n-butane/methane separation factor of 26 and n-butane permeability of 19 000 Barrer were estimated when 30% hydrophilic silica was added to PMP, resulting in a simultaneous increase in n-butane/methane selectivity and n-butane permeability, in contrast to the more conventional trade-off relationships between selectivity and permeability in polymers. The addition of fumed silica in PMP enables this polymer to challenge PTMSP in terms of both efficiency and productivity, as it disrupts the molecular packing by fillers, which in turn causes a redistribution of the free volume (Merkel et al, 2002). 

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