2-Methyl-6-vinylpyridine

The other main source of various pyridopyridazines from pyridines are the [4 + 2] cycloaddition reactions, already mentioned (Section 2.15.8.3), between vinylpyridines and azodicarboxylic esters (79T2027, 79KGS639) or triazolidinediones e.g. 78KGS651). 2-Vinyl-pyridines gave reduced pyrido[3,2-c]pyridazines (370), 4-vinylpyridines gave [3,4-c] analogues, whilst 2-methyl-5-vinylpyridine furnishes a mixture of the [2,3-c] and [4,3-c] compounds. Yields are low, however, and these remain curiosities for practical synthetic purposes. 

A catalytic quantity of potassium in pyridine solution catalyzed the Michael-type addition of carbazole to 2- and 4-vinylpyridine giving 29 (R = 35 and R = 36) comparable addition to 2-methyl-5-vinylpyridine... 

Fig. 19. Dependence of the parameter m/ 0 on the volume fraction of ethanol, Qo, in the mixture with water for PAA gel in the isoelectric point containing quatemized 2-methyl-5-vinylpyridine and SMA units (I) and for the neutral PAA gel (2) The content of SMA units is 3.67 mol %, BAA-0.21 mol %. 4>0 = 0.039, T = 25 °C. Reproduced from Ret [15]...

By chemical agents, indirect grafting on Nylon in liquid phase is frequently referred to in the bibliography. The most common reagent is air (144) or ozone, under controlled conditions, in order to avoid deterioration on the mechanical properties of the fiber, which is then immersed in the monomer. Hence, styrene (145-149), vinylidene chloride (146), vinyl acetate (146), acrylic and methacrylic acids (149), methyl methacrylate (146), acrylonitrile (146,148,149), 2-methyl-5-vinylpyridine (149) were successfully employed as grafting comonomers. 

Stearamidomethylpyridinium chloride is used in waterproofing textiles. It is made by reacting pyridine hydrochloride with stearamide and formaldehyde. Vmylpyridines are used as components of acrylonitrile copolymers to improve the dyeability of polyacrylonitrile fibers. Tile commercially important products are 2-vinylpyndine 4-vinylpyndine and 2-methyl-5-vinylpyridine. Formulas are shown below. 

Under copolymerization, the preferred sorption of one of the monomers on the matrix leads to enriching the daughter chains with this monomer. For instance, Polovinsky showed that MA — methyl methacrylate 85) and MA-styrene 86) copolymers, formed in the presence of a PEO matrix, are enriched in MA, the constants of copolymerization depending on the concentration of the matrix. It is shown by Kargina et al. 87) that in the presence of a PPh-Na matrix copolymers of 2-methyl-5-vinylpyridine and AA are considerably enriched in the cation monomer up to complete elimination of AA and formation of homopoly-2-methyl-5-vinylpyridine. 

In the present paper we pay special attention to block polymers with polypropylene and polyethylene as the initial anionic block. However, both crystalline and amorphous block polymers of ethylene and propylene, butadiene, and several other olefins and dienes have been made by the AFR technique. The second or free radical block has been made from 4-vinylpyridine, 2-methyl-5-vinylpyridine, and mixtures with other monomers, as well as a number of acrylic monomers. Vinyl chloride, vinylidine chloride, vinyl acetate, and several related monomers have not been successfully copolymerized. 

Of the three most common vinylpyridines, 4-vinylpyridine and 2-methyl-5-vinylpyridine are approximately equivalent in terms of the amount incorporated into block polymers, while 2-vinylpyridine is about one-fourth as reactive. 

Monomer Concentration. When 2-methyl-5-vinylpyridine is used alone, the incorporation or conversion of the monomer to block polymer is low, of the order of 10% of monomer used. However, conversion of vinylpyridine is increased greatly by the presence of acrylonitrile (Table II). Table II also shows that a lower temperature favors conversion, with 50°C. being optimum. Conversion at 70°C. is lower than at 30°C., even when twice the peroxide is used. 

The amount of vinyl pyridine used has some effect on incorporation of acrylonitrile. At half the level of 2-methyl-5-vinylpyridine (1.0 gram) a smaller conversion of acrylonitrile is noted. However, conversion of 2-methyl-5-vinylpyridine is increased somewhat at the lower level. 

The effect of styrene on conversion of 2-methyl-5-vinylpyridine and acrylonitrile is quite dramatic, as shown in Table VI. Surprisingly, the incorporation of both methylvinylpyridine and acrylonitrile increases with the addition of styrene, but styrene itself is not incorporated to any appreciable extent. The low temperature of block polymerization (30°C.) may have been responsible for this selectivity. In subsequent work to be reported on at a later date, it was observed that styrene itself can be introduced as a block during the anionic portion of the polymerization, and that this anion was particularly attractive as an anchor for free radical block formation. From this it may be concluded that styrene serves mainly in the anionic rather than the free radical phase of the block polymerization. 

Two grams 2-methyl-5-vinylpyridine, 3.2 grams acrylonitrile, 0.1-0.2 gram benzoyl peroxide. 

PMVPD PNA POD PODMI POEDE poly(2-methyl-5-vinylpyridine) polylsodium acrylate) polyoctadecene-1 poly(N-(n-octadecyl)maleimide) poly(oxyethylene)dodecyl ether... 

Gechele, G. B. Crescentini, L., "Phase Separation, Viscosity, and Thermodynamic Parameters for Poly-2-methyl-5-vinylpyridine- Diluent Systems," J. Polym. Sci., Part A., 3, 3599 (1965). 

Acrylamide, 2-methyl-5-vinylpyridine and /V-vinylpyrrolidone can be polymerized under similar conditions, and also after decomposition of a monomer-peroxide complex. On the other hand, styrene, methyl methacrylate, isoprene, methyl acrylate, vinyl acetate and ascorbic acid do not polymerize under these conditions. Complex formation between persulphate and these monomer donors is more favourable energetically [165]. The complex is more stable, it is not decomposed into initiating radicals and polymerization does not occur. 

In methanol it is built into the copolymer much more rapidly than the non-ionized 2-methyl-5-vinylpyridine... 

On the other hand, in a more polar medium, 2-methyl-5-vinylpyridine is faster. 

Kagan. H. S. and Ardashev, B. I.. Mannich reaction with 2-methyl-5-vinylpyridine, Khim. Geterotsiki Soedin.. 1066, 1%8 Chem. Abstr. 70, 77740, 1%9. 

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