Phenyl isopropenyl ketone

Aromatic groups provide a convenient chromophore for UV absorption. Copolymers of isopropenyl phenyl ketone (IPPhK) with MM A show spectral sensitivity up to the mid-UV range (Table 3.3) (7J). P(IPPhK-MMA) (28 72) is 10 times more sensitive than PMIPK when exposed to the full output of a Xe-Hg lamp. 

Hudrlik and Kulkarni have shown that a-t-butyldimethylsilyl aldehydes serve as vinyl cation equivalents for the synthesis of /3,y-unsaturated ketones (and esters). Addition of lithium enolates to the a-silyl aldehydes is highly erythro-selective, enabling products of either E- or Z-geometry to be obtained (Scheme 58). In a related process, phenylselenoacetaldehyde has been used to transform ketones into the corresponding a-vinylketones (Scheme 59) phenyl-selenoacetone enables a- isopropenylation of ketones in an analogous fashion. ... 

VIII POLY (STYRENE-CO - PHENYL ISOPROPENYL KETONE) (PS-PIPK)... 

Poly(phenyl isopropenyl ketone-co-M M A) [P(PhlPK-MMA)] 10 Copolymer with MMA(28 72) 71... 

Preparation of Monomers. Methyl vinyl ketone (MVK) was obtained from Pfizer Chemical Division, New York, and distilled to remove the inhibitor. Methyl isopropenyl ketone (MIPK) was prepared by the aldol condensation of methyl ethyl ketone and formaldehyde, according to the method of Landau and Irany 0. The major impurity in this monomer is ethyl vinyl ketone (5. The monomer was redistilled before use. 3 Ethyl 3 buten 2 one (EB) was prepared by the aldol condensation of methyl propyl ketone and formaldehyde. Ethyl vinyl ketone (EVK) was prepared by a Grignard synthesis of the alcohol, followed by oxidation to the ketone. t-Butyl vinyl ketone (tBVK) was prepared from pinacolone and formaldehyde by the method of Cologne (9). Phenyl vinyl ketone (PVK) was prepared fay the dehydrochlorlnatlon of 0 cbloro propiophenone (Eastman Kodak). Phenyl isopropenyl ketone (PPK) was prepared by the Mannich reaction using propiophenone, formaldehyde and dimethylamine HCl. 

The procedure involves reaction in acetic anhydride, or in another solvent, followed by the addition of acetic anhydride to decompose the intermediate complex. The procedure has been extensively examined in relation to the 5-methyl- and 4,5-dimethyl-substituted compounds derived from ethenyl methyl and methyl isopropenyl ketones and with mesityl oxide which gives the 3,3,5-trimethyl-substituted compounds. Amongest the phosphorus reactants, the trichloride itself and methyl- " , ethyl- " " and phenyl- phosphonous dichlorides have been employed, as have ethyl and phenyP dichlorophosphites, ROPCI2. The use of 2-thienylphosphonous dichloride to give 137 is recorded as is that of the unsaturated ketone 138 to give 139. A more novel conversion is that of 140 into 141 in 25% yield with a similar conversion (15%) being observed for cholest-4-en-3-one. ... 

Poly(styrene-co-phenyl isopropenyl ketone) (PS-PIPK) VIII... 

Both UV- and y-irradiation have been applied successfully for the initiation of methyl isopropenyl ketone [349-351] and phenyl vinyl ketone polymerization [341]. Since polymerization initiated by y-irradiation was inhibited by chinone, a radical mechanism was proposed. 

Conjugate addition was almost quantitative for the reaction between di- -butyl zinc or tri-n-butyl aluminum and both methyl isopropenyl ketone and phenyl vinyl ketone. With 2-furyl vinyl ketone an increase in initiator concentration produced crosslinking of the material [353]. 

UV and y-radiation of poly(methyl isopropenyl ketone) produced random chain scission at 23 °C. The presence of air increases unexpectedly the main chain scission of the polymer under y-radiation [377]. In a series of publications [378] the radiolysis and photolysis of poly(phenyl vinyl ketone), poly(vinyl benzophenone), and poly(/-butyl vinyl ketone) [357] were described. The authors stated that photodegradation of poly (phenyl vinyl ketone) occurred by the abstraction of a hydrogen in the y-position to a carbonyl group, followed by chain scission by a Norrish type II photoelimination mechanism. 

Poly(phenyl isopropenyl ketone-co-acrylic acid)... 

Photodegradation of poly(phenyl isopropenyl ketone) (or poly(2-methyl-l-phenyl-2-propen-l-one) (3.21) occurs by the following mechanism, which includes [1541-1543] ... 

The triplet lifetime and the quantum yield of the chain scission ( J of copolymers of phenyl isopropenyl ketone and methyl methacrylate are independent of copolymer composition, indicating that the photolysis of the phenyl isopropenyl ketone moieties is not influenced by neighbouring methyl methacrylate units. 

Copolymers of the phenyl isopropenyl ketone and styrene undergo P-cleavage (Type II Norrish process) according to reaction ... 

The extent of this process increases with decreasing phenyl isopropenyl ketone content, i.e. with increasing probability of the phenyl isopropenyl ketone moieties having styrene units as nearest neighbours. 

Photodegradation of poly(acrylic acid [449, 1952] occurs by mechanisms similar to those described for poly(methacrylic acid) (cf section 3.4.2). There are several papers devoted to the photodegradation of polycarboxylic acid esters such as poly(vinyl acetate) [335-337, 519, 749, 750, 1482, 2147, 2173] (cf section 3.4.4), poly(vinyl propionate [335-337], poly(vinyl butyrate) [1480], and copolymers such as poly(acrylic acid-co-phenyl isopropenyl ketone) [1465], poly(vinyl acetate-co-ethylene [335-337,2003], poly(vinyl acetate-coethylene) blends with poly(vinyl chloride [2005] and poly(vinyl acetate-cophenyl vinyl ketone [1208, 1209]. 

Poly(methyl methacrylate-co-phenyl isopropenyl ketone) 1194, 1540, 1541,... 

Poly(styrene-p-ring substituted (Cl, OH, NH2, NO2) phenyl isopropenyl ketone)... 

A macromolecular chain presents a unique reaction situation in which, in certain cases, groups which are potential reactants at elevated temperature are located in close proximity. Thus intramolecular cyclization may occur, which may or may not involve elimination of small molecules. For example, vinyl ketone polymers such as poly(methyl vinyl ketone) (PMVK), poly(methyl isopropenyl ketone) (PMIK) and poly(phenyl vinyl ketone) undergo random cyclization of adjacent monomer units with release of water. The reaction for PMVK is illustrated in Scheme 4. 

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