Ethylene methoxycarbonylation

Perhydropyrido[l,2- ]pyrazin-l-one was prepared in the reaction of methyl pipecolinate and ethylene imine in boiling EtOH <19951JSP5461047>. Cyclocondensation of ethyl 2-amino-2-(2-pyridyl)acetate with DMAD, followed by treatment of reaction mixture with NaOMe, gave the 2-(l-methoxycarbonyl)-4-oxo-47/-pyrido[l,2- ]pyrazin-3-yl)acetate <1996JHC639>. 

Poly(methyl acrylate) Poly[l-(methoxycarbonyl)ethylene]... 

Cyclic ketene acetals can also react with amines to give 1,1-enediamines with elimination of ethylene glycol76. Treatment of 2-[(methoxycarbonyl)cyanomethylene]-1,3-dioxolane (38) with 1,3-diaminopropane or with 4,5-dimethyl-1,2-phenylenediamine gives the hexahydropyrimidine and the benzimidazoline derivatives 39 and 40, respectively (equation 11). Similarly to the reaction of ketene dithioacetals with amines, the reaction between ketene acetals and amines proceeds via monoamino-substituted intermediates and ketene 7V,Oacetals can be isolated when one molar amine is used72. 

Methyl methacrylate (MMA) is an important commodity since it is polymerized to give poly methylmethacrylate (PMMA), a strong, durable and transparent polymer sold under the trade-names Perspex and Plexiglas. Since the conventional routes to MMA involve either the reaction of acetone with HCN to give the cyanohydrin (which has environmental problems), or the oxidation of isobutene, alternative carbonylation routes to MMA are being developed. One of these is the Lucite Alpha process which is claimed to decrease production costs by ca. 40%. This first synthesizes methyl propionate by a methoxycarbonylation of ethylene (Equation 23), using a palladium catalyst with very high (99.8%) selectivity. In the second step, MMA is formed in 95% selectivity by the reaction of methyl propionate with formaldehyde (Equation 24). 

Palladium catalysts with simple monodentate phosphine ligands (e.g. PPh3) can catalyze the methoxycarbonylation of ethylene. However, the Lucite process employs a bulky diphosphine, 1,2-( Bu2PCH2)2CgH4, and is highly active and selective under quite mild conditions (10 bar/80°C). Two alternative catalytic cycles are possible, based either upon a palladium hydride or a palladium methoxide complex (Figure 9), and mechanistic and spectroscopic studies indicate that the hydride cycle is dominant. The alkene and CO insertion steps are the same as those in the Pd-catalyzed co-polymerisation of CO and alkenes to polyketones (Section 4.4). 

In the 1980s Drent and colleagues at Shell found a remarkable change in catalytic behaviour when monodentate phosphines were replaced with certain bidentate diphosphines. Cationic palladium(II) catalysts generated in methanol from Pd(OAc)2, PPhs and the acid of a weakly coordinating anion (e.g. tosylate, triflate) catalyzed the methoxycarbonylation of ethylene to... 

METHOXYCARBONYL CHLORIDE (79-22-1) Forms explosive mixture with air (flash point 54°F/12°C). Reacts with moisture in air, forming hydrogen chloride fumes. Reacts slowly with water or steam, forming hydrochloric acid, carbon dioxide gas, and methanol. Violent reaction with alkali metals, dialkylzincs, dimethyl formamide, dimethyl sulfoxide, ethers, ethylene glycol diethyl ether, strong oxidizers. Incompatible with strong bases, alcohols. Corrodes metals in the presence of moisture. Attacks some plastics, rubber, and coatings. 

Poly[l-(methoxycarbonyl)-l-phenylethylene)] (atactic) Poly[l-(methoxycarbonyl)-l-phenylethylene)] (isotactic) Poly[l-methyl-l-(phenethoxycarbonyl)ethylene] Poly[l-methyl-l-(phenoxycarbonyl)ethylene]... 

Triflic acid-catalyzed Friedel-Crafts acylation reactions of aromatics with methyl benzoate give benzophenone products in good to excellent yields (eq 33). To explain the high level of electrophilic reactivity of this system, protosolvated species are proposed as possible intermediates (eq 32). In the triflic acid-catalyzed cyclization of some ethylene dications, protonation of the ester group is thought to be a key activation step. Reaction of a-(methoxycarbonyl)diphenylmethanol with TfOH gives the fluorene product in 94% yield (eq 34). ... 

Poly (l-(methoxycarbonyl) ethylene). See Polymethyl acrylate Polymethyl acrylate CAS 9003-21-8... 

When the disodium salt of l,2-bis(methoxycarbonyl)ethane phosphonic acid is applied, poly(ethylene terephthalate) with the structure given below was obtained [93,94]. It was found that the polycondensation stage proceeds normally at 1-9% (by weight) of the... 

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