Methyl methacrylate Diels-Alder reactions

Heteroatom functionalized terpene resins are also utilized in hot melt adhesive and ink appHcations. Diels-Alder reaction of terpenic dienes or trienes with acrylates, methacrylates, or other a, P-unsaturated esters of polyhydric alcohols has been shown to yield resins with superior pressure sensitive adhesive properties relative to petroleum and unmodified polyterpene resins (107). Limonene—phenol resins, produced by the BF etherate-catalyzed condensation of 1.4—2.0 moles of limonene with 1.0 mole of phenol have been shown to impart improved tack, elongation, and tensile strength to ethylene—vinyl acetate and ethylene—methyl acrylate-based hot melt adhesive systems (108). Terpene polyol ethers have been shown to be particularly effective tackifiers in pressure sensitive adhesive appHcations (109). 

The Diels-Alder reaction of methyl methacrylate with cyclopentadiene was studied [72] with solutions from three different regions of the pseudophase diagram for toluene, water and 2-propanol, in the absence and in the presence of surfactant [sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium bromide (HTAB)]. The composition of the three solutions (Table 6.11) corresponds to a W/O-fiE (A), a solution of small aggregates (B) and a normal ternary solution (C). The diastereoselectivity was practically constant in the absence and in the presence of surfactant a slight increase of endo adduct was observed in the C medium in the presence of surfactant. This suggests that the reaction probably occurs in the interphase and that the transition state has a similar environment in all three media. 

Table 6.11 Diastereoselectivity of Diels-Alder reaction of methyl methacrylate with cyclopentadiene performed in ternary solutions...

Holt studied the Diels-Alder reaction in a mixture of water, 2-propanol, and toluene as microemulsions.33 The endo/exo ratio between the reaction of cyclopentadiene and methyl methacrylate was enhanced with increasing amount of water in the presence of a surfactant. 

The reactivity of 4,6-benzo[/ ][l,7]naphthyridine in Diels-Alder reactions with maleic acid and dimethyl acetylenedicarboxylate was examined. The reaction afforded adduct 332 (1996MI5). 6-Ethoxycarbonyl- 333a and phenacylmethylides 333b were used as 1,3-dipolar reagents in reactions with methacrylic acid, methyl methacrylate, butyl vinyl ether, methyl vinyl ketone, maleic anhydride and dimethyl acetylenedicarboxylate (1996MI5, 1999AJC149). 

The use of molten salts based on phosphonium tosylates has also been reported for Diels-Alder reactions [175]. These salts have higher melting points than most ionic liquids in common use and hence the reactions were performed in a sealed tube. The authors claim very high selectivities in the reaction of isoprene with MVK or methyl acrylate. The effect of temperature on the selectivity in phosphonium tosylates gave reduced endoxxo ratios at higher temperatures [176]. The Diels-Alder reactions of isoprene with acrylonitrile, acrylic acid and methacrylic acid in pyridinium ionic liquids ([EtPy][BF4] or [EtPy][F3CC02]) were found to give the expected cyclohexene structures [177]. The authors show that... 

The Alder rule is not perfect. It correctly predicts the major product from the Diels-Alder reaction of 1,3-cyclopentadiene with methyl acrylate, but is incorrect in the case of methyl methacrylate. On the basis of these facts, give the structure of the major product isolated in each case. 

Diels-Alder cycloaddition is an organic chemical reaction between a conjugated diene and a substituted alkene to form a substituted cyclohexene system [62]. Polymer-supported chloroaluminates, poly(l-butyl-4-vinylpyridinium) chloroaluminate, poly(l-butyl-3-vinylimidazolium) chloroaluminate, and poly(l-ethyl-3-vinylimidazolium) chloroaluminate were synthesized, and their activities were tested for the Diels-Alder reaction of cydopentadiene with methyl methacrylate [63]. These polymer-supported heterogeneous catalysts exhibited activities comparable to their corresponding monomeric homogeneous analogs and could be reused with a moderate loss of initial activity up to five runs. 

Diols are efficient bidentate ligands for Lewis acid metals such as Ti(IV). Starting from Merrifield resin, alkyl spacer-tethered 1,2- and 1,3-diol functionality was easily introduced to the cross-linked polymer [63]. The resulting polymer (130) containing diol functionality was treated with TiCU in toluene for 18 hours to give the polymer-supported Ti(IV) Lewis acid (132) (Scheme 19.26). These polymeric Ti(IV) catalysts were used for Diels-Alder reaction of cyclopentadiene (134) and methyl methacrylate (135). Although the polymer-supported Ti(IV) (132) catalyzed the reaction, their activities were lower than that of the nonsupported diol-Ti(IV) catalyst (131). 

The addition of 2,3-dimethyl-1,3-butadiene to 17 gives only one structural isomer, 21. The pseudo-first order half-life of this Diels-Alder addition reaction is 47.5 minutes at 22.2°C in neat diene solution. The Ea of this reaction is estimated to be 9.2 kcal/mol. This reaction rate is 50 times faster than the rate of addition of this diene to methyl methacrylate (33). 

The participation of Diels-Alder type intermediates in polymerization was considered by Hill et ah (26) in 1939 as a result of the elucidation of the structures of the butadiene homopolymer and the butadiene-methyl methacrylate copolymer resulting from thermal polymerization in emulsion. The considerable amount of alternating 1,4 and 1,2 structures in the homopolymer and the predominantly 1,4 structure of the butadiene in the copolymer which contained more than 50% alternating units of butadiene and methyl methacrylate led to the proposal that the reaction proceeded through a Diels-Alder dimer complex or activated complex. Chain initiation involved a thermal reaction in which the activated com-... 

Diels-Alder click reactions have been successfully used for the preparation of well-de ned star polymers. Devise methodologies using this route to prepare 3-arm star polymers with uniform arms, core-As, where A is (a) poly(ethylene glycol), (b) poly(methyl methacrylate), and (c) poly(tert-butyl... 

The unsaturated sites in alkyds are capable of undergoing further reactions such as Diels-Alder (maleic acid or anhydride [23,66], cyclo-pentadiene [67]) and polymerization [68] in the presence of catalysts or other monomers, styrene [69], vinyl toluene [70, 71], methyl methacrylate [72], acrylic [72], and acrylonitrile [73]. 

MA Diels-Alder adducts, 118, 119, 158, 159 MA ene reaction, 119, 158, 159 MA equimolar copolymerization, 270, 273 MA-metal complex polymerization, 212 maleate and fumarate copolymerization, 365, 369 maleimide copolymerization, 266, 365 MA nonequimolar copolymerization, 270-298 MA reactivity ratios, 302 methyl methacrylate copolymerization with MA CTC, 370... 

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