Vinyl esters acetals

Vinyl acetate- Acetic acid vinyl ester Acetic acid ethenyl ester, (108-05-4), 65, 135 VINYL CATION EQUIVALENT, 66, 95 Vinyl cation synthons, 66, 102 Vinyl radical cyclization, 66, 81, 82 VINYLAT10N OF EN0LATES. 66, 95, 104 Vinyl lithium, 66, 53, 55... 

Alkoxylation with, for example, propylene oxide (PO). Preferred amine is triethanolamine, or ammonia and other alkanolamines used amine can also be quaternized Best example is triethanol with 14.9 PO units Contains vinyl ester acetal functionalities besides some unreacted vinyl alcohol monomer units. Preferred aldehyde is butyraldehyde Backbone, for example, polyalkylene glycol, polyalkyl-eneimine, polyether, or polyurethane, and active functional side groups made from grafting VP or VCap to backbone using radical initiators TBA (tributylammonium groups)... 

Acetic acid vinyl ester Acetic acid ethenyl ester 65, 135... 

Catalytic vinylation has been appHed to a wide range of alcohols, phenols, thiols, carboxyUc acids, and certain amines and amides. Vinyl acetate is no longer prepared this way in the United States, although some minor vinyl esters such as stearates may still be prepared this way. However, the manufacture of vinyl-pyrrohdinone and vinyl ethers still depends on acetylene. 

Hydrolysis of vinyl acetate is catalyzed by acidic and basic catalysts to form acetic acid and vinyl alcohol which rapidly tautomerizes to acetaldehyde. This rate of hydrolysis of vinyl acetate is 1000 times that of its saturated analogue, ethyl acetate, ia alkaline media (15). The rate of hydrolysis is minimal at pH 4.44 (16). Other chemical reactions which vinyl acetate may undergo are addition across the double bond, transesterification to other vinyl esters, and oxidation (15—21). 

Poly(vinyl alcohol) can be derived from the hydrolysis of a variety of poly(vinyl esters), such as poly(vinyl acetate), poly(vinyl formate), and poly(vinyl ben2oate), and of poly(vinyl ethers). However, all commercially produced poly(vinyl alcohol) is manufactured by the hydrolysis of poly(vinyl acetate). The manufacturing process can be viewed as one segment that deals with the polymeri2ation of vinyl acetate and another that handles the hydrolysis of poly(vinyl acetate) to poly(vinyl alcohol). 

Vinyl esters are prepared by the reaction of a fatty acid with either acetjfene in direct condensation or vinyl acetate by acidolysis. 

The thermoplastic or thermoset nature of the resin in the colorant—resin matrix is also important. For thermoplastics, the polymerisation reaction is completed, the materials are processed at or close to their melting points, and scrap may be reground and remolded, eg, polyethylene, propjiene, poly(vinyl chloride), acetal resins (qv), acryhcs, ABS, nylons, ceUulosics, and polystyrene (see Olefin polymers Vinyl polymers Acrylic ester polymers Polyamides Cellulose ESTERS Styrene polymers). In the case of thermoset resins, the chemical reaction is only partially complete when the colorants are added and is concluded when the resin is molded. The result is a nonmeltable cross-linked resin that caimot be reworked, eg, epoxy resins (qv), urea—formaldehyde, melamine—formaldehyde, phenoHcs, and thermoset polyesters (qv) (see Amino resins and plastics Phenolic resins). 

Poly(vinyl alcohol) is thus prepared by alcoholysis of a poly(vinyl ester) and in practice poly(vinyl acetate) is used (Figure 14.5). 

Of the higher vinyl ester homopolymers only poly(vinyl propionate) is currently believed to be of commercial value, being marketed as Propiofan (BASF) for surface coating application where greater alkali resistance is possible than with the normal vinyl acetate based copolymers. 

As an extension of this work, these authors have applied this catalyst system to vinylogous asymmetric Mukaiyama-type aldol reactions, involving silyl vinyl ketene acetals and pyruvate esters. These reactions afforded the corresponding y,5-unsaturated a-hydroxy diesters with quaternary centres in high yields and enantioselectivities of up to 99% ee (Scheme 10.25). It was shown that the presence of CF3CH2OH as an additive facilitated the turnover of the catalyst. 

Laurie acid, 30, 106 31, 69 Lauric acid, vinyl ester, 30,106 Laurone, 31, 68 Lauroyl chloride, 31, 68 Lead acetate trihydrate, 31, 19 Lead sulfide, 31, 19... 

Determination of acetic acid, vinyl ester in food simulants... 

Vinyl acetate Acetic acid vinyl ester (8) Acetic acid ethenyl ester (9) (108-05-4)... 

Synonyms Acetic acid, ethenyl ester Acetic acid, ethylene ester Acetic acid, vinyl ester 1-Acetoxyethylene AI3-18437 BRN 1209327 CCRIS 1306 EINECS 203-545-4 Ethenyl acetate Ethenyl ethanoate Everflex 81L NSC 8404 UN 1301 Unocal 76 Res 6206 Unocal 76 Res S-55 VAc VAM Vinnapas 850 Vinyl acetate H.Q. Vinyl A monomer Vinyl ester of acetic acid Vinyl ethanoate Zeset T. 

Acetic acid, vinyl ester, see Vinyl acetate... 

The transfer vinylation between carboxylic acids 64 and vinyl acetate 65 was also achieved under the influence of [IrCl(cod)]2 and NaOAc in this way a variety of carboxylic acids were converted into the corresponding vinyl esters 66, with excellent yields (Equation 10.12 and Scheme 10.7) [28]. 

Vinyl acetate was produced by the catalytic acetylation of acetylene, but this monomer is now produced by the catalytic oxidative condensation of acetic acid and ethylene (structure 17.32). Other vinyl esters can be produced by the transesterification of vinyl acetate with higher boiling carboxylic acids. 

It should be pointed out that the raw materials for VAM and its related polymers (i.e. ethylene and acetic acid) are produced from fossil resources, mainly crude oil. It is possible to completely substitute the feedstock for these raw materials and switch to ethanol, which can be produced from renewable resources like sugar cane, com, or preferably straw and other non-food parts of plants. Having that in mind, the whole production of PVAc, that nowadays is based on traditional fossil resources, could be switched to a renewable, sustainable and C02-neutral production process based on bioethanol, as shown in Fig. 3. If the vinyl acetate circle can be closed by the important steps of biodegradation or hydrolysis and biodegradation of vinyl ester-based polymers back to carbon dioxide, then a tmly sustainable material circle can be established. 

For all practical purposes, monomeric vinyl alcohol exists only in its tautomeric form as acetaldehyde. Therefore, poly(vinyl alcohol) (PVAlc) is prepared by the hydrolysis of polymers of vinyl esters. For practical reasons, the starting material of choice is poly(vinyl acetate) (PVAc). Although hydrolysis may be carried out under acidic conditions, alkaline conditions in the presence of an alcohol are preferred. The reaction may be represented by... 

---