Insoluble resins

CH2=CHC = CCH = CH2. a colourless liquid which turns yellow on exposure to the air it has a distinct garlic-like odour b.p. 83-5°C. Manufactured by the controlled, low-temperature polymerization of acetylene in the presence of an aqueous solution of copper(I) and ammonium chlorides. It is very dangerous to handle, as it absorbs oxygen from the air to give an explosive peroxide. When heated in an inert atmosphere, it polymerizes to form first a drying oil and finally a hard, brittle insoluble resin. Reacts with chlorine to give a mixture of chlorinated products used as drying oils and plastics. 

When exposed to sunlight, it is converted to a white insoluble resin, disacryl. Oxidized by air to propenoic acid small amounts of hy-droquinone will inhibit this. Bromine forms a dibromide which is converted by barium hydroxide into DL-fructose. The acrid odour of burning fats is due to traces of propenal. It is used in the production of methionine and in controlled polymerization reactions to give acrolein polymers. ... 

Phenolic resins were the first totally synthetic plastics invented. They were commercialized by 1910 [I]. Their history begins before the development of the structural theory of chemistry and even before Kekule had his famous dreams of snakes biting their tails. It commences with Gerhardt s 1853 observations of insoluble resin formation while dehydrating sodium salicylate [2]. These were followed by similar reports on the behavior of salicylic acid derivatives under a variety of reaction conditions by Schroder et al. (1869), Baeyer (1872), Velden (1877), Doebner (1896 and 1898), Speyer (1897) and Baekeland (1909-1912) [3-17]. Many of these early reports appear to involve the formation of phenolic polyesters rather than the phenol-aldehyde resins that we think of today. For... 

An interesting development of this research is the preparation of polymer-supported FITS reagent from bis(trifluoroacetoxy)iodoperfluoroalkanes and Nafion-H [145]. FITS-Nafion reacts with organic substrates that react to usual FITS reagents, but the products of the perfluoroalkylation reaction can be separated easily from the insoluble resin by filtration [145]... 

The resinification of 2-furaldehyde promoted by acidic substances or by heat has been known to chemists since the end of last century, and attempts to explain the mechanism leading to the formation of black, insoluble resins have been published... 

A particulate gel breaker for acid fracturing for gels crosslinked with titanium or zirconium compounds is composed of complexing materials such as fluoride, phosphate, sulfate anions, and multicarboxylated compounds. The particles are coated with a water-insoluble resin coating, which reduces the rate of release of the breaker materials of the particles so that the viscosity of the gel is reduced at a retarded rate [205]. 

Normally the reaction Is useful for the conversion of alkyl halides to primary amines without concomitant formation of secondary amines.29 Treatment of polymer 17 with hexamethylenetetramine in a mixture of ethanol/THF afforded an insoluble resin. Using diazabicyclooctane (DABCO), we demonstrated that the reaction could be limited to attack by a single nitrogen in a multifunctional amine, so we did not anticipate crosslinking via bis-quat salt formation. Hydrolysis of 2 with anhydrous HC1 in ethanol generated free amino groups as evidenced by a positive ninhydrin test, but quantitative hydrolysis could not be achieved and the product remained insoluble. One would have expected a simple bis-quat to hydrolyse and open the crosslinked structure. 

The polyester sizes used have a much lower average molecular mass than polyester fibres. These structures (10.69) contain sulphonic acid groups and may be water-soluble or water-dispersible types. The degree of sulphonation is low [171]. If these resins are subjected to a high pH, the sulphonate groups can be hydrolysed, giving an insoluble resin that is very difficult to remove from the fibres. 

An ionic surfactant or phase-transfer catalyst can also be immobilized by binding it to an insoluble resin. The binding is generally covalent (Brown and Jenkins, 1976 Brown and Lynn, 1980) but it can be coulombic (Brown et al., 1980) the catalysts are re-usable and product separations are also simplified. 

The most important alkyds are obtained from glycerol and phthalic anhydride. A linear polymer can be obtained by heating them at 180°C in ratio 2 3 (i.e., excess of acid). This polymer when heated forms cross-links and yields a thermosetting insoluble resin. 

A number of modifications of the structure of the allylstannane have been prepared with the aim of facilitating the removal of tin from the product. These include Curran s fluorous allylstannane (see Section 3.14.04.1), Pereyre s monoallylstannane AllylXSn[N(TMS)2]2 (Equation (92) above),258 allylstannanes with a polar (oligoethylene oxide) tail (e.g., 23 and 24), and the allylstannyl group bonded to a soluble or insoluble (cross-linked) polystyrene. The reaction using the allylstannane bonded to a soluble, uncross-linked, polystyrene resin occurs about 100 times faster than that on the cross-linked, insoluble resin, and the polymer can be recovered by recrystallization from methanol. 

The alkaline hydrolysis of the ether-insoluble resin glycoside fraction from seeds of Ipomoea nil (L.) Roth (syn. Pharbitis nil Choisy) yielded a pentasaccharide of ipurolic acid, which was named pharbitic acid C (tetradecanoic acid, ll-[(0-6-deoxy- S-D-glucopyranosyl-(1 4)-0-6-deoxy-a-L-mannopyranosyl-(l—>6)-0-[6-deoxy-a-L-mannopyranosyl-(l—>2)-0-jS-D-glucopyranosyl-(l—>2)]- S-D-glucopyra-nosyl)oxy]-3-hydroxy). On complete hydrolysis, it produced two o-glucoses, two L-rhamnoses, one o-quinovose, and the aglycone moiety (77). 

Du X-M, Sun N-Y, Nishi M, Kawasaki T, Guo Y-T, Miyahara K (1999) Components of the Ether-Insoluble Resin Glycoside Fraction from the Seed of Cuscuta australis. J Nat Prod 62 722... 

Ono M, NodaN, Kawasaki T, Miyahara K (1990) Resin Glycosides. VII. Reinvestigation of the Component Organic and Glycosidic Acids of Pharbitin, the Crude Ether-Insoluble Resin Glycoside ( Convolvulin ) of Pharbitis Semen (Seeds of Pharbitis nil). Chem Pharm Bull 38 1892... 

Ono M, Nakagawa T, Kawasaki T, Miyahara K (1993) Woodrosins I and II, Ether-Insoluble Resin Glycosides from the Stems of Ipomoea tuberosa. Chem Pharm Bull 41 1925... 

The cationic polymerization of 2-vinylfuran with strong acids can be allowed to proceed to black crosslinked resins which display a remarkable proton affinity when swelled in organic solvents (19). Their very high Lewis basicity can be exploited to scavenge Bronsted acids the insoluble resin is easily removed by filtration at the end of the operation and readily regenerated by neutralization with a strong Bronsted base. 

Resinous materials have also been made directly from molasses for example, Vazquez describes a resin that is made by merely heating molasses with sulfuric acid and a solvent such as acetone or ethyl acetate. The extract, on evaporation, gave a hard insoluble resin which could be molded. 

Direct sequestration of a reactant by an insoluble resin is impractical if the kinetics is sluggish and impossible if the solution-phase reactant does not contain a functionality to enable direct sequestration. These limitations led several research groups to use bifunctional solution-phase linking reagents, also referred to as sequestration-enabling-reagents. 33... 

Although hydrogen chloride has been the catalyst principally employed in the Fischer method, other acids, notably sulfuric acid, have been used, as well as acidic, ion-exchange resins.66-19 The advantage of the latter reagents is that the insoluble resin can be readily filtered from the reaction solution. It is held that the replacement of soluble acids by insoluble resins does not appreciably alter the formation of the glycofuranosides. 

For some uses it is important to form bonds that link different polysilane chains, to transform soluble, meltable polysilanes into insoluble resins. This process is vital if the polysilanes are to be used as precursors to silicon carbide ceramics, since, if cross-linking is not carried out, most of the polymer is volatilized before thermolysis to silicon carbide can take place. Several methods have therefore been developed to bring about cross-linking of polysilanes.109 110... 

Discussion In principle, acetals are cleaved by acid-catalyzed hydrolysis. In most cases aqueous acetic acid, aqueous trifluoracetic acid, dilute HC1 in THF or DOWEX 50W (H+) resin are used. Thus, treatment of 6 with DOWEX ion exchange resin in methanol rapidly furnishes the corresponding 1,2-diol without any further chromatographic purification steps. Generally, polymer supported reagents benefit from the ease of removal from the reaction mixture just by filtration of the insoluble resin. The resulting diol is acetylated by addition of acetic anhydride and pyridine. Final acetal exchange is achieved by acetic anhydride and catalytic amounts of concentrated sulfuric acid. A mixture (2 1) of anomers is obtained. 

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