Poly acrolein

Monomer Synthesis. Three processes are used commercially for the manufacture of acrolein, CH2=CH—CHO  

Dehydration of glycerol with KHSO4, AI2O3, or H3PO4 at about 190°C (obsolete method). 

The oxidation of propylene at 370°C with 0.4% CU2O on carborundum. In the synthesis, a hydrogen atom is eliminated from the methyl group and an allyl radical is formed. 

Polymerization and Properties. In the free radical polymerization of acrolein, a copolymer is formed with the monomeric units  

The ladder structure is responsible for the relatively high glass-transition temperature (85°C). The copolymers contain about 4 % vinyl double bonds, which result from polymerization via the aldehyde groups. Depending on initiator and reaction conditions, ionic polymerization leads to polymerization via the aldehyde or the vinyl group or both. A 1,4-polymerization of the kind found in butadiene has not yet been established. Several polymers are at the pilot-plant stage. 

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Polymere Ketone [z.B. Poly-(methyl-vinyl-keton), Styrol/Methyl-vinyl-keton-Copolymere] werden durch Natriumboranat in Bis-[2-methoxy-athyl]-ather bei 60-90° nur zu 40-60%, in N-Methyl-morpholin bei 115° durch Lithiumalanat dagegen vdllig reduziert5 und Poly-(chalkone) mit Natriumboranat in Bis-[2-methoxy-athylj-ather ebenfalls quantitativ6. Die Reduktion von Poly-acrolein zum Poly-allylalkohol gelingt mit Kalium-boranat in Wasser7. 

The surfactant is an important component of this process and acts to stabilize the growing polymeric particles by surface adsorption. Phase separation and the formation of solid particles occur before or after termination of the polymerization process [42]. Polymerization can occur in some systems without the presence of surfactants [40]. Various particulate systems have been prepared by this method, including poly(styrene) [43], poly(vinylpyridine) [44, 45], poly(acrolein) [46, 47], and poly(glutaraldehyde) [48-50],... 

Papers concerning the physical properties of polymers as the guest components in urea inclusion compounds and polymerization reactions of guest monomer molecules within the urea tunnel structure have been reviewed elsewhere. The polymers studied included poly (ethylene), poly (acrylonitrile), poly (1,3-butadiene), poly(eth-ylene oxide), poly(tetrahydrofiiran), poly(acrolein), poly(vinyl chloride), poly(ethyl acrylate), poly(lactide), poIy(lactic acid), poly(ethylene adipate). poly(ethylene succinate), acrylonitrile-ethyl acrylate copolymer, and poly(hexanediol di acrylate). 

The attachment of iron chelating ligands to polymers is an alternative means of modifying bioavailability. DFB has been covalently bonded to poly(acrolein) and other synthetic polymers and shown to have some potential for use in extracorporeal detoxification of acute iron overloaded plasma (57). Poly(N-methacryl-oyl-6-alanine hydroxamic acid), a polydentate polymer obtained by derivatization of poly(acrylic acid) with pendant hydroxamic acid groups, has shown significant iron chelation activity in vivo (58), a result which is possibly related to the longer retention of polymeric species in the circulatory system. 

Biocatalysts that are reversibly soluble as a function of pH have been obtained by the covalent coupling of lysozyme to alginate (113) of trypsin to poly(acrolein-co-acrylic acid) (114) and of cellulase (115), amylase (115) a-chymotrypsin, and papain (116) to poly(methyl methacrylate-co-methacrylic acid). A reversibly soluble cofactor has been produced by the covalent binding of NAD to alginate (117). Reversibly soluble a-chymotrypsin, penicillin acylase, and alcohol dehydrogenase were produced by coupling to the polycation component of polyelectrolyte complexes formed by poly(methacrylic acid) and poly(iY-ethyl-4-vinyl-pyridinium bromide) (118). 

The monomer is soluble in numerous solvents however, the polymer precipitates from most of these solvents at about 15% conversion during radical polymerization. Molecular weights up to 100,000g/mol and aldehyde contents above 65% can be achieved when the polymerization is carried out in polar solvents such as DMF, y-butyrolactone, or pyridine by means of hydroperoxides and nitrous acid derivatives as redox catalysts [68]. Deviations from this behavior are observed if DMF is used as solvent and the polymerization is initiated by AIBN. A microgel is formed here after 16% conversion the clear reaction solution turns into a transparent gel [69]. Polymerization in the presence of methanol initiated by means of azo compounds or peroxides does yield soluble poly(acrolein), presumably because of the polymer s molecular weight [70]. 

Short poly(acrolein) blocks were formed, if a,co-disodium oligobutadiene (initiated with sodium naphthalene in THF at — 40°C) was treated with... 

Radically Polymerized Acrolein (Redox Poly (acrolein))... 

Because of the insolubility of redox poly (acrolein) [129], modification reactions must always start in heterogeneous systems and lead to soluble products gradually. The already presented water-soluble products of the reaction between poly(acrolein) and Na2S03 or H2SO3 [76-78] are still better precursors for modification reactions than is native redox poly (acrolein). They permit a reaction performance in homogeneous media. 

In this way poly(acrolein) particles may play an important role as immunoreagents for biological research. 

Poly(acetaldehyde-co-chloral) Fractional precipitation Poly(acrolein-co-thiophenolmercaptal) Chloroform/methanol 1457 2911... 

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