Alcohols epoxidation poly

Polyether. A polymer in which the repeating unit includes a carbon-oxygen bond derived from aldehydes, epoxides, poly alcohols or similar materials (Refs 1 4a). 

Table 5.2 Asymmetric epoxidation of cis- and trans-allylic and homoallylic alcohols using poly(octamethylene tartrate)/Ti(Oz Pr)4/TBHP. 

Flexible linear macromolecules make up, as mentioned before, the newest class of molecules and are the molecules most important to man. Their number is practically unlimited. For examples, almost all textile fibers are flexible macromolecules, from cotton, silk, wool, hair, and rayon to nylon, polyesters, and aramid. Many structural materials are also flexible macromolecules, such as lumber, compmsites, polyoxyethylene, poly(vinyl chloride), and nylon. Because of the ease of melting, many flexible macromolecules have earned the name plastics, such as polyethylene, polypropylene, polytetra-fluoroethylene, and polyoxides. Many adhesives such as glues, epoxides, poly-(vinyl alcohol), cyanoacrylic polyesters, and ethylene-vinyl alcohol copolymers are based on flexible macromolecules. The unique combination of viscosity and elasticity in the liquid state makes many flexible macromolecules useful as elastomers, of which natural and synthetic robbers and segmented polyurethanes are best known. Class 2 also includes the biolo cal macromolecules carbohydrates, proteins, and DNA. The biological macromolecules alone are practically unlimited in number, as documented by the variety of forms of life. 

Cationic poly(vinyl alcohol) has been prepared by the reaction of A/-(3-chloro-2-hydroxypropyl)-Ai,Ai,A/-trimethylammonium chloride, PVA, and sodium hydroxide (143). Reactions between alkyUdene epoxide and PVA in particulate, free-flowing form in an alkaline environment have been reported (144). 

Canali et al.17 reported the use a linear poly(tartrate) ligand in the asymmetric epoxidation of allylic alcohols. Moderate results were obtained. They also reported the use of branched/crosslinked poly(tartrate), which gave moderate to good results in the asymmetric epoxidation of allylic alcohols. As shown in Scheme 4-9, when L-(+)-tartaric acid and 1,8-octanediol are heated... 

Poly(octamethylene tartrate) can be used directly in place of dialkyl tartrates in the Sharpless epoxidation of allylic alcohols. 

Use of poly(octamethylene tartrate) in place of dialkyl tartrates offers practical utility since the branched polymers yield hetereogeneous Ti complex catalysts which can be removed by filtration. Overall the work-up procedure is considerably simplified relative to the conventional Sharpless system. In addition, significant induction is shown in the epoxidation of (Z)-allylic alcohols[7] and even with homoallylic[8] species where the dialkyltartrates give very poor results Figure 5.3. Table 5.2 is illustrative of the scope using the polymer ligand. 

HMX HMX HMX HMX HMX HMX HMX HMX HMX HMX HMX HMX HNS NTO NTO/HMX NTO/HMX NTO/HMX PETN PETN PETN PETN PETN PETN PETN PETN PETN PETN RDX RDX RDX RDX RDX RDX RDX RDX RDX RDX RDX RDX RDX TATB/HMX Cariflex (thermoplastic elastomer) Hydroxy-terminated polybutadiene (polyurethane) Hydroxy-terminated polyester Kraton (block copolymer of styrene and ethylene-butylene) Nylon (polyamide) Polyester resin-styrene Polyethylene Polyurethane Poly(vinyl) alcohol Poly(vinyl) butyral resin Teflon (polytetrafluoroethylene) Viton (fluoroelastomer) Teflon (polytetrafluoroethylene) Cariflex (block copolymer of butadiene-styrene) Cariflex (block copolymer of butadiene-styrene) Estane (polyester polyurethane copolymer) Hytemp (thermoplastic elastomer) Butyl rubber with acetyl tributylcitrate Epoxy resin-diethylenetriamine Kraton (block copolymer of styrene and ethylene-butylene) Latex with bis-(2-ethylhexyl adipate) Nylon (polyamide) Polyester and styrene copolymer Poly(ethyl acrylate) with dibutyl phthalate Silicone rubber Viton (fluoroelastomer) Teflon (polytetrafluoroethylene) Epoxy ether Exon (polychlorotrifluoroethylene/vinylidine chloride) Hydroxy-terminated polybutadiene (polyurethane) Kel-F (polychlorotrifluoroethylene) Nylon (polyamide) Nylon and aluminium Nitro-fluoroalkyl epoxides Polyacrylate and paraffin Polyamide resin Polyisobutylene/Teflon (polytetrafluoroethylene) Polyester Polystyrene Teflon (polytetrafluoroethylene) Kraton (block copolymer of styrene and ethylene-butylene)... 

Oxidation is the first step for producing molecules with a very wide range of functional gronps because oxygenated compounds are precursors to many other prodncts. For example, alcohols may be converted to ethers, esters, alkenes, and, via nncleophilic substitution, to halogenated or amine products. Ketones and aldehydes may be used in condensation reactions to form new C-C double bonds, epoxides may be ring opened to form diols and polymers, and, finally, carboxylic acids are routinely converted to esters, amides, acid chlorides and acid anhydrides. Oxidation reactions are some of the largest scale industrial processes in synthetic chemistry, and the production of alcohols, ketones, aldehydes, epoxides and carboxylic acids is performed on a mammoth scale. For example, world prodnction of ethylene oxide is estimated at 58 million tonnes, 2 million tonnes of adipic acid are made, mainly as a precursor in the synthesis of nylons, and 8 million tonnes of terephthalic acid are produced each year, mainly for the prodnction of poly(ethylene terephthalate) [1]. 

Hydrocarboxylation of the Ce-Cs a-olefins with cobaltcarbonyl/pyridine catalysts at 200 °C and 20 MPa gives predominantly the linear carboxylic acids. The acids and their esters are used as additives for lubricants. The Ce-Cio a-olefins are hydroformylated to odd-numbered linear primary alcohols, which are converted to polyvinylchloride (PVC) plasticizers with phthalic anhydride. Oligomerization of (preferably) 1 -decene, applying BF3 catalysts, gives oligomers used as synthetic lubricants known as poly-a-olefins (PAO) or synthetic hydrocarbons (SHC) [11, 12]. The C10-C12 a-olefins can be epoxidized by peracids this opens up a route to bifunctional derivatives or ethoxylates as nonionic surfactants [13]. 

L-24 as a ligand, up to 85—90% yield. The linking reaction of a poly(tBA) with a bromide terminal was also possible with divinylbenzene, whereas the other two divinyl compounds led to side reactions.328 The yield of star polymers can be increased up to 95% with the use of additives. The a-end-functionalized linear polymers afford surface-functionalized star polymers with various functional groups such as alcohols, amines, epoxides, and nitriles. 

Golub (16) found, using Ir and NMR, that functional groups of epoxide and alcohol are mainly formed In the oxidation of poly-butadlene in the temperature range of 90-180°C. These two products suggest the addition of the peroxy radical to the double bond to form an alkoxy radical and an epoxide group ... 

Yoshida and co-workers reported the oxidation of alcohols mediated by cross-linked poly(4-vinylpyridininium bromide) in the presence of a small amount of water (Figure 12.5) [16]. The electrolysis can be carried out without intentionally added electrolyte, and therefore ketone products are easily separated by simple filtration and the mediator can be recovered and re-used. This method has also been applied successfully to the oxidation of sulfides, epoxidation of olefins, and side-chain oxidation of alkylbenzenes. A similar polymeric system has also been reported by Zupan and Dolenc [17]. 

A heterogeneous version of the Sharpless [73] epoxidation of allylic alcohols has been described [74], A complex formed between Ti(OPr )4 and a linear poly-L-tar-trate, in combination with zeolite 4A as a drying agent, catalyzed the enantio-selective epoxidation of tra/iJ-2-hexen-l-ol with TBHP (92 % yield and 79 % ee), although not all of the titanium remained complexed to the polymer on recycling and was uncomplexed or complexed with tartrate monomer/oligomer in solution. 

A number of hydroxylated water soluble polymers were examined as coreactants with polymer 52 in the absence of calcium alginate, and were judged on the basis of the rate of gel formation and the physical properties of the gel These polymers included sodium alginate, polyvinyl alcohol, and copolymers of HEMA with MAA. Of the polymers tested, best results were obtained with polymer 10a, a copolymer of HEMA with a mole fraction of about 10% MAA, which rapidly produced an elastic gel on exposure to polymer 52 in solution. Simple condensation of the carboxyls in polymer 10a with the epoxide functionality was ruled out as a competing reaction due to the measurable but slow reaction between polymer 52 and poly methacrylic acid. It is, therefore, likely... 

A general synthesis for all diastereomeric L-hexoses, as an example for monosaccharides that often do not occur in the chiral pool, has been worked out. The epoxidation of allylic alcohols with tertiary butyl hydroperoxide in presence of titanyl tartaric ester catalysts converts the carbon-carbon double bond stereose-lectively to a diol and is thus ideally suited for the preparation of carbohydrates. The procedure is particularly useful as a repetitive two-carbon homologiza-tion in total syntheses of higher monosaccharides and other poly hydroxy compounds. It starts with a Wittig reaction of a benzylated a-hydroxy aldehyde with (triphenylphosphoran-ylidene)acetaldehyde to produce the olefinic double bond needed for epoxidation. Reduction with sodium-borohydride... 

Methods of Preparation of Hydrophobically Modified WSPs (HMWSPs). Incorporation of Hydrophobes into WSPs. Water-soluble cellulose derivatives ((hydroxyethyl)cellulose, (hydroxypropyl)cellulose, methylcellulose, etc.) or synthetic polymers containing hydroxyl groups (e.g., poly(vinyl alcohol)) can be reacted with a long-chain alkyl halide (2), acyl halide (2), acid anhydride (6), isocyanate (2), or epoxide (2, 3) under appropriate conditions to form an HMWSP. These reactions are shown in Scheme I. These postmodifications can be done in solution or in hetero-... 

Since the network density is changed by the reaction between epoxide and alcohol or water, the mechanical properties of the resulting polymer are also influenced. This can be used, for example, in the flexibiHzation of dental materials with poly(l,4-butanediol) [11] or coatings with polyester polyols [12]. It is not only alcohols that influence the polymerization kinetics and the properties of the polymer, but also carboxylic acids. By the addition of a polymer with carboxylic acid groups instead of the polyol, a polyester is formed as a reaction product and not a polyether. This was examined in detail by Wu and Soucek [13]. 

A fascinating triphase catalyst has been developed this past year for catalytic epoxidation of allylic alcohols. The combination of phosphotungstic acid with an amphiphilic poly(fV-isopropylacrylamidc)-dcrived polymer provides a macroporous complex 5, which functions as a recoverable catalyst in aqueous conditions. Thus, treatment of allylic alcohol 6 with 0.003 mol% catalyst 5 and 2 equiv of hydrogen peroxide in aqueous medium resulted in the formation of the corresponding epoxide 7 in 96% yield. The catalyst exhibits... 

---