Butyraldehyde polymerization

Table IV gives an example of our own work on the polymerization of a number of higher aldehydes. Potassium triphenylmethoxide—a soluble initiator—polymerized a number of higher aldehydes to crystalline isotactic poly aldehydes. Table V lists a number of alkali alkoxides and other related compounds used as initiators for the n-butyraldehyde polymerization. Neither the type of the alkoxide nor the cation is of any great importance for the polymerization rate, the polymer yield, and stereoregularity of the resulting polyaldehyde as long as the initiator is adequately soluble in the reaction mixture.

Figure 3. Conversion in n-butyraldehyde polymerizations potassium triphenylmethoxide (0.2 mole %) as initiator in 25% pentane solutions A = by gas chromatography, 0 = isolated and weighed. A = time dependence of conversion at -75° C. B = temperature dependence of conversion after 10 minutes reaction time...

In solvents of high dielectric constant, (e.g. dimethylformamide), formaldehyde polymerized sluggishly and polymers were formed in low yield. In similar solvents, aliphatic aldehydes could not be polymerized. Precipitated aldehyde polymers have the tendency to absorb monomers. The monomer concentration near the propagating site may be much hi er than that in the surrounding solution. This occurs with n-butyraldehyde polymerizations in pentane [5] the polymer precipitated during the polymerization is highly swollen by the monomer. 

Vinyl coatings are used primarily on metal surfaces. They provide excellent protection by their strong cohesive forces, although their adhesion to the metal is not good. Used with a phosphoric acid-containing primer to etch the metal surface, this adhesion is markedly improved. The primer also contains poly(vinyl butyral) and is approximately 0.2-0.3 mil thick (1 mil = 1/1000th inch). Poly(vinyl butyral) is made from polymerized vinyl acetate by hydrolysis and reaction with butyraldehyde. 

The manufacture of linear low-density polyethylene (LLDPE) by slurry polymerization in hexane (see Sections 6.2 and 6.8) is carried out by Hoechst, Mitsui, and a number of other chemical manufacturers in a series of continuous stirred tank reactors. The manufacture of butyraldehyde from CO, H2, and propylene using a soluble rhodium phosphine complex (see Sections 5.2 and 5.5) is also carried out in a continuous stirred tank reactor. 

Figure 2. Influence of the dielectric constant e of various solvents upon the polymerization of n-butyraldehyde. Initial reaction temperature, -75° C. time, one-half hour initiator, potassium triphenylmethoxide (0.13 mole %) solvent, n-butyraldehyde (ratio, 4 1)...

Polymerization of aldehydes can be accomplished only at low temperatures. The influence of temperature on aldehyde polymerization initiated by potassium triphenylmethoxide is shown in Figure 3 with n-butyraldehyde as the example. At -78° C. the polymerization goes to high conversions (95%) the conversion decreases substantially with increasing temperature. No polymerization is observed above -15° C. 

Dialkylzinc initiates homo- and copolymerization of aldehydes such as acetaldehyde 151, 234, 310, 487, 533), formaldehyde 310, 495), butyraldehyde 468), glutardehyde 386), cyanopropionaldehyde 479), chloroacetaldehyde 233, 234, 324, 325, 412, 495, 533), and dichloro-acetaldehyde 325). Aluminum triisopropoxide 485) and phosphorus compounds 339) were proposed as additives for the polymerizations. Polymerization of optically active aldehydes was also reported ). 

Butyl nitrite decomposes slowly on standing and should be kept in a cool place and used within a few days or, at most, a few weeks after it is prepared. A sample which stood for five months during a warm summer seemed to contain only 20-25 per cent of the original nitrite. The products of decomposition consist of oades of nitrogen, water, butyl alcohol, and polymerization products of butyraldehyde. 

Higher aldehydes, for example acetaldehyde or n-butyraldehyde, have much less tendency to polymerize compared to formaldehyde [5, 6]. Reasons have been given in thermodynamic terms by referring to the lower enthalpy of polymerization (about —7 kcal mole" ) as compared to formaldehydes (—12 kcal mole" ), which results in ceiling temperatures of —40°C. In terms of reactivity, aliphatic aldehydes undergo hydration and hemiacetal formation to an extent of about 50%. 

The only useful conversion—time curve for an anionic aldehyde polymerization has been obtained for 1 n-butyraldehyde (25% solution in pentane) at —78°C with potassium triphenyl methoxide (Fig. 23) [59]. The conversion was determined from polymer weight and monomer remaining in solution. It was shown that the polymerization is very rapid and an 80% conversion is reached in 5 min. 

In addition to chloral the polymerization of other chlorinated aldehydes was studied by Kambe et al., for example that of oi-chloro iso-butyraldehyde. It was also found in this case that the initiation was almost instantaneous and the growing polymer ends could be acetylated when acetylation was carried out immediately at the low polymerization... 

BUTYRALDEHYD (German) (123-72-8) Forms explosive mixture with air (flash point I0°F/—12°C). Can form explosive peroxides with air polymerization may occur. Incompatible with strong oxidizers, strong acids (with elevated temperature and pressure), caustics, amines, ammonia. 

Oily liquid. Characteristic odor. Breathing of vapor causes headache and vasodilation, dj 0.9114. bp1M 78.2 (some decompn). Miscible with alcohol, ether. Dec on storage. Polymerization products of butyraldehyde have been found in five-month -old samples. 

The propagation reaction continues after polymer precipitation, because the precipitated macromolecules are highly swollen by the monomers. This was shown in polymerizations of n-butyraldehyde in heptane. The physical state of the polymers and the surface areas of their crystalline domains therefore influence the paths of the polymerizations. 

Bromo-2-fluoro biphenyl intermediate, foam builders Alkenyl succinic anhydride intermediate, food additives Soy acid Stearyl alcohol intermediate, food emulsifiers Caprylic/capric acid Tallow acid intermediate, food supplements (tablet form) Cetyl alcohol intermediate, food wrap Vinylidene chloride monomer intermediate, fragrances p-t-Butyl toluene t-Butyl-m-xylene Citral Cyclopentanone Diethyl toluene diamine Dimethyl hexynediol 1,2-Methylenedioxybenzene 2-Methylpentanal Myrcene n-Propyl bromide intermediate, fragrances cosmetics Acetic anhydride n-Butyraldehyde n-Butyric acid Butyric anhydride 2-Ethylhexoic acid Isobutyric anhydride 2-Methylpropanal Propionic anhydride intermediate, fragrances personal care Butyric anhydride Isobutyric anhydride intermediate, free-radical polymerization initiators... 

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