Vinyl acetate, reaction with

Vinyl acetate reacts with the alkenyl triflate 65 at the /3-carbon to give the 1-acetoxy-1,3-diene 66[68]. However, the reaction of vinyl acetate with 5-iodo-pyrimidine affords 5-vinylpyrimidine with elimination of the acetoxy group[69]. Also stilbene (67) was obtained by the reaction of an excess of vinyl acetate with iodobenzene when interlamellar montmorillonite ethylsilyl-diphenylphosphine (L) palladium chloride was used as an active catalyst[70]. Commonly used PdCl2(Ph3P)2 does not give stilbene. 

Although not a Michael acceptor, vinyl acetate reacts with a range of carbanions under phase-transfer catalytic conditions [61]. 1 1 Adducts are obtained from 1-cyano-l-phenylalkanes, but phenylacetonitrile produces a 2 1 adduct with loss of acetic acid (Scheme 6.28). The major product (40%) isolated from the reaction with diphenylmethyl cyanide is l,2-dicyano-l,l,2,2-tetraphenylethane. 

The synthesis of poly(vinyl acetals) (252) represents another example of generating a heterocycle, in this case the 1,3-dioxane nucleus, by application of a polymer modification reaction. Generally, the polymer modified is poly(vinyl alcohol) (180) or one of its copolymers. The 1,3-dioxane ring is generated (Scheme 122) by an acid-catalyzed acetalization reaction with an aldehyde, although ketones have also been reacted. A review (71MI11102) is available covering synthesis, properties and applications of the two most common and industrially important poly(vinyl acetals), poly(vinyl butyral) and poly(vinyl formal), as well as many other functional aldehydes that have been attached. 

Cyclization of acyclic acetals.3 Reaction of the y-hydroxy-y-vinyl acetal (1) with SnCl4 (1 equiv.) in CH2C12 at -78° provides cw-hydroindenes 2 and 3, which are convenient precursors to the dione 4. 

The vinyl acetate reaction is even more sensitive. With S = 44.2 for the side reaction alone it would be virtually impossible to try to prevent an adiabatic reactor from reaching full conversion on oxygen by mere control of the inlet temperature. Small changes in the inlet conditions would quickly amplify down the reactor, forcing complete conversion, adiabatic temperature rise, and destruction of the catalyst, if we were lucky in the best scenario. We must apply external cooling to the vinyl acetate reactor. 

Similarly, the ratio of the reaction rate (k, ) of a vinyl acetate terminus with ethylene monomer to the reaction rate (k ) of a vinyl acetate terminus with vinyl acetate provides a different reactivity ratio (r ) ... 

Some over-all reactions of the ethylene-to-vinyl acetate process with either PdCl2 + CuCl2 or with Pd(OCOCH.3)o + Cu(OCOCH3)2 as catalysts are formulated in Table XV. Simplified flowsheets of the one-stage and two-stage processes are shown in Figures 1 and 2. 

Fresh ethylene and recycled gas are compressed to 150 p.s.i.g. and pumped into the reactor where the reaction is carried out at 120°-130°C. The latter contains a suspension of catalyst and promoters suspended in acetic acid. Recovered acetic acid and fresh acid and oxygen are pumped into the reactor. A supply of HCl (not shown) is also necessary. Excess ethylene, containing vinyl acetate, acetaldehyde, and a small amount of H2O and acetic acid, is expanded to ca. 50 p.s.i.g. by flash distillation. At this point, acetaldehyde is separated from vinyl acetate. The bottoms from the acetaldehyde still will contain all the vinyl acetate together with HgO and acetic add. Vinyl acetate is separated from the HtO by a decanter and distilled to remove HiO and light ends. Subsequently, the bottom from this distillation is submitted to a final distillation to give pure vinyl acetate. Acetic add is recovered by distillation. 

The anion (26) of the isoquinoline Reissert compound (2) has been used in a Michael-type reaction. Thus, reaction of 26, generated with phenyllithium, with ethyl cinnamate and substituted cinnamates give rise to 63, dimethyl acetylenedicarboxylate yields 64, and 2- and 4-vinylpyridines give rise to 65. Use of cinnamonitrile in this sequence leads to the isolation of 66. The enol ester, vinyl acetate reacts with the isoquinoline Reissert compound in aqueous sodium hydroxide containing TEBA chloride to surprisingly give 67. ... 

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