Pentaerythritol, synthesis

Formaldehyde also does not contain an a-H atom. However, formaldehyde is such a reactive electrophile that it tends to undergo multiple aldol additions instead of a simple aldol condensation. This type of reaction is exploited in the pentaerythritol synthesis. 

Another ester synthesis employs the reaction of a long-chain ketone and pentaerythritol in xylene or chlorobenzene (14). Mixed esters have been produced using mixed isostearic and cyclohexane carboxyUc acids in trihromophosphoric acid, followed by reaction with lauric acid (15). 

Albright Wilson s Antiblaze 100. The synthesis (81) involves reaction of pentaerythritol and phosphoms trichloride to produce a... 

PETN was first prepared in 1894 by the nitration of pentaerythritol, PE (Ref 1). This is still the basic method used today. Commercial production of PETN could not be realized until the formaldehyde and acetaldehyde required in the synthesis of PE became readily available about a decade before WWII... 

A combination of anionic and ATRP was employed for the synthesis of (PEO-b-PS) , n = 3, 4 star-block copolymers [148]. 2-Hydroxymethyl-l,3-propanediol was used as the initiator for the synthesis of the 3-arm PEO star. The hydroxyl functions were activated by diphenylmethyl potassium, DPMK in DMSO as the solvent. Only 20% of the stoichiometric quantity of DPMK was used to prevent a very fast polymerization of EO. Employing pentaerythritol as the multifunctional initiator a 4-arm PEO star was obtained. Well-defined products were provided in both cases. The hydroxyl end groups of the star polymers were activated with D PM K and reacted with an excess of 2-bromopropionylbro-mide at room temperature. Using these 2-bromopropionate-ended PEO stars in the presence of CuBr/bpy the ATRP of styrene was conducted in bulk at 100 °C, leading to the synthesis of the star-block copolymers with relatively narrow molecular weight distributions (Scheme 72). 

Scheme 4. Synthesis of tetramannosylated pentaerythritol having an extended linker.75...

H. Al-Mughaid and T. Bruce Grindley, Synthesis of a nonavalent mannoside glycodendrimer based on pentaerythritol, J. Org. Chem., 71 (2006) 1390-1398. 

The dihydroxylation of alkenes is a useful sttategy for the synthesis of polyols and these can be nitrated to the corresponding nitrate esters. Evans and Gallaghan " synthesized both the mono- (74) and di- (70) allyl ethers of pentaerythritol and used these for the synthesis of some novel nitrate ester explosives. 

Marans and Preckel " synthesized both the mononitrate (95) and the dinitrate (92) esters of metriol by using a similar strategy to that used for pentaerythritol trinitrate. Thus, nitration of both the mono- (90) and the di- (93) acetate esters of metriol, followed by selective hydrolysis of the acetate groups, yields (92) and (95) respectively the latter could be useful as a monomer for the synthesis of energetic polyurethane polymers. 

Uses. As a chemical intermediate in synthesis of acetic acid, pentaerythritol, and pyridine in the production of perfumes, polyester resins, and dyes and as a food preservative and flavoring agent... 

A crossed Cannizzaro reaction is similar to a normal Cannizzaro reaction however, two different aldehydes are reacting. Normally one of the aldehydes is formaldehyde because there are fewer chances for side reactions. (It also has the advantage of being cheap.) The reactions in Figures 11-34 and 11-35 are crossed Cannizzaro reactions using an excess of formaldehyde. The excess of formaldehyde increases the probability of the initial attack by the hydroxide being on the formaldehyde instead of the other aldehyde. Figure 11-35 shows the synthesis of pentaerythritol. 

Polyacetal resins have a repeating unit of -O-CH2-. They are strong, stiff polymers for valves, hoses, and tube connectors. Pentaerythritol finds end-uses in alkyd resins and explosives (pentaerythritol tetranitrate). To appreciate this synthesis, the student should review two condensation reactions, the crossed aldol and the crossed Cannizzaro. Acetaldehyde reacts with 3 mol of formaldehyde in three successive aldol condensations. This product then undergoes a Cannizzaro reaction with formaldehyde. 

A similar method was applied in the synthesis of a polyester-vinyl graft copolymer in which a polyester of pentaerythritol dibromide and... 

The use of polyols such as pentaerythritol, mannitol, or sorbitol as classical char formers in intumescent formulations for thermoplastics is associated with migration and water solubility problems. Moreover, these additives are often not compatible with the polymeric matrix and the mechanical properties of the formulations are then very poor. Those problems can be solved (at least partially) by the synthesis of additives that concentrate the three intumescent FR elements in one material, as suggested by the pioneering work of Halpern.29 b-MAP (4) (melamine salt of 3,9-dihydroxy-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]-undecane-3,9-dioxide) and Melabis (5) (melamine salt of bis(l-oxo-2,6,7-trioxa-l-phosphabicyclo[2.2.2]octan-4-ylmethanol)phosphate) were synthesized from pentaerythritol (2), melamine (3), and phosphoryl trichloride (1) (Figure 6.4). They were found to be more effective to fire retard PP than standard halogen-antimony FR. 

To avoid dissolution or extraction of the FR, FR oligomer can be used instead of monomer. Using this approach, Ma et al.39 reported the synthesis of phosphate-polyester copolymers from spirocyclic pentaerythritol di(phosphate acid monochloride)s. It was shown that LOI of the copolymer increases with increasing phosphate content to reach a maximum of 30 vol %. 

FIGURE 6.13 Synthesis scheme of poly(2-hydroxy propylene spirocyclic pentaerythritol bisphosphonate or PPPBP. (From Chen, D.Q. et al., Polym. Deg. Stab., 88, 349, 2005.)... 

Liu, Y. and Wang, Q. 2006. Catalytic action of phospho-tungstic acid in the synthesis of melamine salts of pentaerythritol phosphate and their synergistic effects in flame retarded polypropylene. Polym. Deg. Stab. 91 2513-2519. 

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