Pentaerythritol compound

Pentaerythritol is used in self-extinguishing, non dripping, flame-retardant compositions with a variety of polymers, including olefins, vinyl acetate and alcohols, methyl methacrylate, and urethanes. Phosphoms compounds are added to the formulation of these materials. When exposed to fire, a thick foam is produced, forming a fire-resistant barrier (see Elame retardants) (84—86). 

Photocurable materials for photographic films contain pentaerythritol and dialkylamino and/or nitrile compounds, which have good adhesion and peelabihty of the layers, and produce clear transfer images (97,98). 

Formaldehyde condenses with itself in an aldol-type reaction to yield lower hydroxy aldehydes, hydroxy ketones, and other hydroxy compounds the reaction is autocatalytic and is favored by alkaline conditions. Condensation with various compounds gives methylol (—CH2OH) and methylene (=CH2) derivatives. The former are usually produced under alkaline or neutral conditions, the latter under acidic conditions or in the vapor phase. In the presence of alkahes, aldehydes and ketones containing a-hydrogen atoms undergo aldol reactions with formaldehyde to form mono- and polymethylol derivatives. Acetaldehyde and 4 moles of formaldehyde give pentaerythritol (PE) ... 

The basic metal salts and soaps tend to be less cosdy than the alkyl tin stabilizers for example, in the United States, the market price in 1993 for calcium stearate was about 1.30— 1.60, zinc stearate was 1.70— 2.00, and barium stearate was 2.40— 2.80/kg. Not all of the coadditives are necessary in every PVC compound. Typically, commercial mixed metal stabilizers contain most of the necessary coadditives and usually an epoxy compound and a phosphite are the only additional products that may be added by the processor. The requited costabilizers, however, significantly add to the stabilization costs. Typical phosphites, used in most flexible PVC formulations, are sold for 4.00— 7.50/kg. Typical antioxidants are bisphenol A, selling at 2.00/kg Nnonylphenol at 1.25/kg and BHT at 3.50/kg, respectively. Pricing for ESO is about 2.00— 2.50/kg. Polyols, such as pentaerythritol, used with the barium—cadmium systems, sells at 2.00, whereas the derivative dipentaerythritol costs over three times as much. The P-diketones and specialized dihydropyridines, which are powerful costabilizers for calcium—zinc and barium—zinc systems, are very cosdy. These additives are 10.00 and 20.00/kg, respectively, contributing significantly to the overall stabilizer costs. Hydrotalcites are sold for about 5.00— 7.00/kg. 

Various polymers, such as polythiourethanes, polythioethers, and polythioacrylates, are used to produce resins which are transparent, colorless and have a high refractive index and good mechanical properties, useful for the production of optical lenses. Higher refractive indices are promoted by sulfur compounds and especially by esters of mercaptocarboxyhc acids and polyols such as pentaerythritol (41) (see Polymers containing sulfur). 

Peroxide curing systems are generally the same for CSM as for other elastomers but large amounts of acid acceptor must be present to complete the cure. A small amount of a polyfunctional alcohol, ie, pentaerythritol (PER) in the compound significantly reduces the amount of base required by acting as a solubiHzer. TriaHyl cyanurate [101-37-17 is an additional cure promoter and leads to higher cross-link density. 

In some cases it may be desired to increase the cross-link density and hence the rigidity independently of the isocyanate-water reaction. Compounds such as glycerol, pentaerythritol and various amines have been employed as additional cross-linking agents. 

As with the flexible foams there has been a shift to the use of polyethers. These are largely adducts based either on trifunctional hydroxy compounds, on tetrafunctional materials such as pentaerythritol or a hexafunctional material such as sorbitol. Ethylene diamine and, it is understood, domestic sugar are also employed. Where trifunctional materials are used these are of lower molecular weight (-500) than with the polyethers for flexible foams in order to reduce the distance between hydroxyl groups and hence increase the degree of cross-linking. 

An even more complicated nomenclature problem arises with the closely related all-oxygen cryptands. These compounds do not utilize nitrogen as the three-chain junction. Most examples of this class of compounds have utilized pentaerythritol or glycerol as the junction. This naturally imparts a somewhat lower flexibility to the molecule than would be present in the nitrogen-containing cases. Structures of two such molecules are illustrated below. 

The reaction sequence to be used as an example will be the bromination of polyhydroxyl compounds by exchange with bromide ion (eqn. 1). In particular, at Bromine Compounds, we are concerned with the bromination of pentaerythritol 1 and dipentaerythritol 2. 

Esterification of the hydroxyl groups with a chromophore contributing acid levels the polarity effects and strengthens the detectability. The method even separates mixed bromo-chloro compounds (Fig. 7). We see the separation of the dinitrobenzoate esters of trichloropentaerythritol (6.67 min.), monobromodichloro-pentaerythritol (7.35 min.), dibromomonochloropentaerythritol (8.11 min.), 5, 4 and 1 (8.99, 10.25 and 11.71 min.), in that order. 

If simple sample pretreatment procedures are insufficient to simplify the complex matrix often observed in process mixtures, multidimensional chromatography may be required. Manual fraction collection from one separation mode and re-injection into a second mode are impractical, so automatic collection and reinjection techniques are preferred. For example, a programmed temperature vaporizer has been used to transfer fractions of sterols such as cholesterol and stigmasterol from a reversed phase HPLC system to a gas chromatographic system.11 Interfacing gel permeation HPLC and supercritical fluid chromatography is useful for nonvolatile or thermally unstable analytes and was demonstrated to be extremely useful for separation of compounds such as pentaerythritol tetrastearate and a C36 hydrocarbon standard.12... 

Four Ru(tpy) + units with or without carborane-type substituents have been linked to a pentaerythritol core. The resulting compounds exhibit only one cyclic voltammetric wave assigned to the simultaneous oxidation of the four metal-based centers [33]. 

Nitro compounds, like quinones, terminate chains in oxidizing compounds where hydroperoxyl radicals are formed. This was proved for the oxidation of polyatomic esters [37] and PP [38], Nitrobenzene retards the initiated oxidation of the following esters tetrapropionate of pentaerythritol, propionate of 2,2-dimethylbutanol, and dipropionate of 2,2-dimethylpro-panediol terminating chains by the reaction with peroxyl radicals [37]. The hydroperoxyl radicals were supposed to be formed as a result of the following reactions ... 

The above mechanism of intramolecularly catalyzed cleavage is possible only for compounds with a N02 group close to the departing NO group. In other words, it can be postulated to follow nitro reduction in erythritol tetra-nitrate (9.8), mannitol hexanitrate (9.9), pentaerythritol tetranitrate (9.10), and perhaps trolnitrate (9.14), but not in isosorbide dinitrate (9.11). 

The best large-scale preparation of cyclobutanone is the reaction of diazomethane with ketene.2 It requires a ketene generator and implies handling of large quantities of the potentially hazardous diazo compound. A more frequently used method for the preparation of cyclobutanone starts from pentaerythritol, the final step being the oxidative degradation of methylenecyclobutane,3,4 which can also be prepared from other precursors.5 A general survey of all methods used to obtain cyclobutanone has been published.6,7... 

The dicarboxylic acids normally employed are phthalic acid or its anhydride, or mixtures of them with, for example, adipic acid or unsaturated acids.The polyhydroxy compounds generally used are glycerol, trimethylolpropane, or pentaerythritol. In the... 

Solvents that have been less extensively used are N-methyl-2-pyrrolidinone and hexamethylphosphoric triamide.183 The author of this article183 also discussed the purification of chlorotrimethylsilane, and the anomalous results that may be obtained from the use of impure reagent have been commented on in the case of analyses of pentaerythritol.184 The various methods available for the bulk purification of methyl sulfoxide have been reviewed,185 and a symposium on this compound reviewed its use as a solvent in selected reactions.186... 

Problem 17.31 Use aldol condensations to synthesize the following useful compounds from cheap and readily available compounds (a) the food preservative sorbic acid, CHjCH=CH—CH==CH—COOH (fe) 2-ethyl-l-hexanol (c) 2-ethyl-l,3-hexanediol, an insect repellant (d) the humectant pentaerythritol, CCCHjOHjo. ... 

Between World War I and II, TNT replaced picric acid as the explosive of choice in munitions. It was also mixed with other compounds to produce more powerful explosives with unique characteristics. Amatol is a mixture containing between 40% and 80% ammonium nitrate and TNT. Pentolite is a mixture of PETN (pentaerythritol tetranitrate) and TNT. Another common explosive mixture is RDX (cyclotrimethylenetrinitramine) and TNT. RDX is an abbreviation for Royal Demolition Explosive. 

Pentaerythritol diphenyl diphosphate Figure 8.4 Spiro Phosphorus Compounds (69)... 

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