Isocyanates hexyl

Examples shown in this chapter are for PMMA. Other polymers can be separated as well. The polymers separated so far (1,2) include polystyrene, poly(a-methylstyrene), polycaprolactone, polycarbonate, poly(hexyl isocyanate), polytetrahydrofuran, poly (vinyl methyl ether), and polyvinylpyrrolidone. 

C22H40O3 111466-59-2) see Orlistat (35,45)-3-hexyl-4 [(27f)-2-hydroxytridecyl]-2-oxetanone (C22H42O3 104872-06-2) see Orlistat n-hexyl isocyanate... 

A few synthetic helical polymers are known to act as chiral selectors.7a,918d l8k i9d i9h ancj are widely used as chiral stationary phases (CSP) in gas or liquid chromatography.73,53 Recently, it has been reported that the preference of one helical sense in isotropic solution can be induced by some interaction between optically inactive polymers and chiral solvents/additives. Examples of this include poly(n-hexyl isocyanate)18d l8k and poly(phenylacetylene)s bearing functional group.19d 19h The polysilane derivatives also show chiral recognition ability in solution at room temperature. Poly(methyl-ft-pinanylsilane) includes two chiral centers per bulky hydrophobic pinanyl side group28 and... 

Cardias Williams and Hale (1999, 2003) studied the effect of the carbon chain length of the isocyanate upon decay resistance of the modified wood. Wood was reacted with butyl or hexyl isocyanate, or HDI in a pyridine/acetone solvent mix. Modified wood was... 

Cyclohexylurea has been prepared by the reaction of cyclo-hexyl isocyanate with gaseous ammonia or ammonium hydroxide, by thermal decomposition of cyclohexyl allophanamide, by treating cyclohexylamine hydrochloride with an aqueous solution of potassium cyanate," by heating nitrosomethylurea with cyclohexylamine, and by heating an ethanolic solution of cyclohexylamine and 3,5-dimethyl-l-carbamylpyrazole. 2,6-DimethyIphenyIthiourea has been synthesized by allowing 2,6-dimethylaniline hydrochloride to react with ammonium thiocyanate. ... 

Itou et al. [60] determined 0II/0C for isotropic solutions of poly(n-hexyl isocyanate) (PHIC) and dichloromethane (DCM) from sedimentation equilibrium data on narrow distribution PHIC samples. Figure 3 shows their results, where the ordinate Mw(0II/0c) represents the osmotic pressure increment on the molar concentration scale. 

Fig. 7. Comparison of experimental phase boundary concentrations between the isotropic and biphasic regions for various liquid-crystalline polymer solutions with the scaled particle theory for wormlike hard spherocylinders. ( ) schizophyllan water [65] (A) poly y-benzyl L-glutamate) (PBLG)-dimethylformamide (DMF) [66-69] (A) PBLG-m-cresoI [70] ( ) PBLG-dioxane [71] (O) PBLG-methylene chloride [71] (o) po y(n-hexyl isocyanate) (PHICH°Iuene at 10,25,30,40 °C [64] (O) PHIC-dichloromethane (DCM) at 20 °C [64] (5) a po y(yne)-platinum polymer (PYPt)-tuchIoroethane (TCE) [33] ( ) (hydroxypropyl)-cellulose (HPC)-water [34] ( ) HPC-dimethylacetamide (DMAc) [34] (N) (acetoxypropyl) cellulose (APC)-dibutylphthalate (DBP) [35] ( ) cellulose triacetate (CTA)-trifluoroacetic acid [72]...

Karol MH, Hauth BA. 1982. Use of hexyl isocyanate antigen to detect antibodies to hexamethylene diisocyanate (HDI) in sensitized guinea pigs and in a sensitized worker. Fund Appl Toxicol 2(3) 108-113. 

Poly(n-alkyl isocyanate) compounds have a rigid helical structure in solution (174). As shown in Scheme 74, a chirally deuterium-labeled isocyanate is polymerized by sodium cyanide to form a product with a very high rotation value (175). The rotation is highly temperature dependent because of the unique chain structure of the product. Interestingly, the reaction of hexyl isocyanate in the presence of 1 mol % of a related chiral analogue leads to a polymer with a high rotation value. The bias of the chain helicity could be induced by living achiral-chiral copolymers. 

Since the addition of dimethylpyrazole to an isocyanate is reversible by heating at 60°C, the product (10) is known as a blocked isocyanate . Now, it has been shown that magnesium triflate, Mg(OTf)2, is highly active as a catalyst in the reaction at 60 °C between an acid and a blocked isocyanate to give an amide. Thus blocked hexyl isocyanate (10) and heptanoic acid (11) when heated in equimolar quantities in CHCI3 at reflux for 1 h in the presence of 1 mol% Mg(OTf)2 gave a quantitative yield of IV-heptyloctamide (12) with evolution of CO2.6... 

A more remarkable and dramatic change in the conformation of helical polymers upon photoirradiation has been observed for the azobenzene-modified poly isocyanates. Polyisocyanates are typical dynamic helical polymers [59,60]. Even the optically inactive poly(n-hexyl isocyanate) (20), which is devoid of stereogenic centers, exists as an equal mixture of right- and left-handed helical conformations. Equilibrium exists in solution between both helices separated by... 

Few other sets of viscosities exist for polymeric nematics. Yang and Shine (1993) obtained three of the Leslie viscosities for monodomains of poly(n-hexyl isocyanate) (PHIC) from rheological measurements in the presence of an electric field, and they obtained values reasonably consistent with the predictions of the Kuzuu-Doi expressions. From monodomains of the polyion PBZT, poly(l,4-phenylene-2,6-benzobisthiazole) in methane sulfonic acid, some of the Leslie-Ericksen parameters have been extracted via light-scattering and magnetic-field-reorientation studies (Berry 198S Srinivasarao and... 

POLYMETHYL METHACRYLATE POLY T-BUTYL METHACRYLATE POLYMETHYL ISOPROPENYL KETONE CROSSLINKED POLYMETHYL METHACRYLATE POLY OLEFIN SULFONES POLY HEXYL ISOCYANATE DIAZOQUINONE PHOTORESIST... 

Polyisocyanates are obtained by anionic polymerization using initiators such as NaCN and organo-lithiums and have the structure of 1-nylon (72).146,147 Polymerization of hexyl isocyanate with a halfmetallocene complex (73) leads to a living polymer,148... 

An excess helicity is induced by the effect of a chiral solvent or additive.41161171172 In the case of poly(hexyl isocyanate), a CD spectrum based on an excess helicity was observed in chiral chloroalkane solvents (Figure 10), and the sign and intensity of the CD... 

Ober and Thomas et al. reported on rod—coil diblock copolymers consisting of poly(hexyl isocyanate) as the rod block and polystyrene as the coil block (Scheme 2).51 53 The polymers (2) were synthesized... 

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... 

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