Epoxidized and acrylic

E. Takahashi, F. Sanda, and T. Endo, Photocationic and radical polymerizations of epoxides and acrylates by novel sulfonium salts. J. Polym. Sci. A Polym. Chem. 2003,41 (23), 3816-3827. 

One could easily put forward many other examples where catalyst preparation has been the basis for new and improved processes, such as methanol synthesis, ethene epoxidation, and acrylic acid production. However, for the topic of this book it is more important to discuss in which ways catalyst preparation has allowed these new developments. 

Comparisons with reference systems are also provided e.g. NDIO is a much better photoinitiator than the well known camphorquinone CQ (Table 1) upon a low intensity source (halogen lamp). This system leads to final tack-free coatings whereas no polymerization is observed with the CQ based system. TMPTA (trimethylol propane acrylate), EPOX ((3,4-epo>ycyclohexane)methyl 3,4-epo ycyclohe ylcarbo5ylate) and DVE-3 (triethylene glycol divinyl ether) are used as representatives of low viscosity monomers. Figure 6 shows that the synthesis of IPN (Fig. 6A epoxide and acrylate conversions 60%) or thiol-ene (Fig. 6B vinylether and trithiol conversions around 100 and 40%, respectively) is very efficient even upon a low intensity LED bulb. 

In the formation of sustainable thermoset resins, epoxidized and acrylated epoxy-dized plant oils and fatty acids have been largely utihzed, as reported from hterature [51]. For composite applications, acrylated epoxydized soy bean oil (AESO) resin is mainly used because it is commercially accessible [52]. The synthesis of AESO is shown Figure 6.10 the carbon-carbon double bonds in the fatty acid chains are modified to append different polymerizable functionalities, such as epoxides and acrylates, to increase the reactivity of the vegetable oils [53], AESO can be cured at room and high temperatures, depending on the initiator, and can be blended with a reactive diluent such as styrene in order to improve the processing flowability and the mechanical performance. Structural applications such as sandwich beams... 

Reaction conditions depend on the reactants and usually involve acid or base catalysis. Examples of X include sulfate, acid sulfate, alkane- or arenesulfonate, chloride, bromide, hydroxyl, alkoxide, perchlorate, etc. RX can also be an alkyl orthoformate or alkyl carboxylate. The reaction of cycHc alkylating agents, eg, epoxides and a2iridines, with sodium or potassium salts of alkyl hydroperoxides also promotes formation of dialkyl peroxides (44,66). Olefinic alkylating agents include acycHc and cycHc olefinic hydrocarbons, vinyl and isopropenyl ethers, enamines, A[-vinylamides, vinyl sulfonates, divinyl sulfone, and a, P-unsaturated compounds, eg, methyl acrylate, mesityl oxide, acrylamide, and acrylonitrile (44,66). 

Acid, alkali, salt -l-l- Pure epoxide, furan, and acrylic cements... 

Electron withdrawing groups on the alkene considerably retard the epoxidation. For example, acrylic esters and acrylonitrile are not reactive, while allyl chloride is about one tenth as reactive as propylene towards TBHP/MoVI.240 The epoxidation of alkenes is completely stereoselective eri-alkenes are exclusively transformed into ds-epoxides and (runs-alkenes into trans-epoxides. Oxygen addition to the double bond preferentially occurs from the less shielded face of the substrate, e.g. in the selective epoxidation of terpenes by r-pentyl hydroperoxide (t-amyl hydroperoxide, TAHP) (equations 67 and 68).225... 

It turns out that it is difficult to use the ketone to control the stereochemistry of the epoxidation. If acrylic acid is used as the dienophile, bromolactonisation of the product 67 gives a mixture of five- 68 and six-membered 69 lactones in 86% yield and a 1 1.5 ratio. Fortunately, treatment of both with an alkyl-lithium makes the same epoxide 70 by ring opening and Sn2 closure of the epoxide.8 The reaction works well only with an electron-withdrawing group X such as SPh that must be removed later. Addition of MeLi to the ketone and elimination gives 62. 

Fig (19) Octalin ketal (163) is converted to kete dithioacetal (164) by the cleavage of ketal function and condensation with carbon disulfide and methyl iodide. Subjection of (164) to the action of dimethylsulfonium niethylide and acid hydrolysis leads to the formation of unsaturated lactone (165).lts furan silyl ether derivative is caused to undergo Diets-Atder reaction with methyl acrylate to obtain salicyctic ester (166) which is converted by standard organic reactions toabietane ether (167). It is converted to aiiylic alcohol (168) by epoxidation and elimination. Alcohol (169) obtained from (168) yields orthoamide which undergoes transformation to amide (170). Its conversion to the previously reported intermediate has been achieved by epoxidation, elimination and hydrolysis. 

An intermolecular iron-catalyzed ring expansion reaction involving epoxides and alkenes provided tetrahydrofurans via radical processes <07CEJ4312>. Cp2TiCl is able to promote cyclization of 2,3-epoxy alcohols containing a p-(alkoxy)acrylate moiety to form tetrahydrofurans <07TL6389>. As shown in the following example, an intramolecular addition of carbon radicals to aldehydes was reported to afford tetrahydrofuran-3-ols... 

N-Alkylation—Secondary Mannich bases can give the corresponding tertiary derivatives by treatment with particular alkylation agents, such as epoxides (affording P-ami-noalcohols) and acrylic derivatives. Tertiary Mannich bases, mostly, are submitted to N-alkylation in order to produce stable quaternary ammonium salts to be subsequently subjected to deamination (Sec. A.2). However, different quaternary ammonium byproducts can be readily given by the reaction. " For instance, a base-catalyzed rearrangement is afforded by allyl ammonium salts 365 (Fig. 144), obtained by N-alkylation of acetylenic Mannich bases with ally] halides. " In the presence of sodium hydride, the compounds 365 yield a wide range of 3-amino-5-hexen-l-yne derivatives 366. 

In another approach to copolymers, linear H-terminated polysiloxanes are hydrosilated to introduce reactive groups. Examples are the addition of allylamine to give reactive intermediates that can be converted to polysiloxane-polyimides or polyamides, and the hydrosilylation of allyl glycidyl ether to produce a silicone that can be copolymerized with epoxides or acrylates (equations 29 and 30). 

Asymmetric Epoxidation of Electron-deficient trans-Olefins. (f )-l can also catalyze epoxidation of electron-deficient trans -olefins, especially ( )-cinnamate derivatives (eq 4). With 5 mol % of (f )-l, epoxidation of acrylate (5) is completed in 27 h with 74% yield and 85% ee. The crude product can be purified using a continuous dissolution and crystallization process to afford enantiomerically pure product and recover the ketone catalyst simultaneously. A similar practical method has been employed for large-scale synthesis of a key intermediate for diltiazem hydrochloride (a potent calcium antagonist for treatment of cardiovascular disease). 

Polyester acrylates and urethane acrylates are in common use.307 Cationic systems use vinyl ethers, such as triethyleneglycol divinyl ether, epoxides, and polyols. These... 

J. V. Koleche, Photochemistry of Cycloaliphatic Epoxides and Epoxy Acrylates, Vol. I., ASTM International, 1989. 

A compatibilizing copolymer may be formed through reaction between carboxylic acid groups grafted onto a PO chain and acrylate epoxide groups grafted onto a PP chain. In an internal mixer Liu et al. [1993] have prepared compositions comprising 20 parts NBR-g-AA, 0-75 parts PP and 0-25 parts PP-g-GMA (0.8% GMA). The blends were characterized by torque rheometry, SEM, FTIR, and mechanical properties vs. use of unfunctionalized NBR and vs. different GMA levels. 

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