Reaction Of Vinyl Acetate Research Articles

Multi-functional oilfield production chemicals: maleic-based polymers for gas hydrate and corrosion inhibition

Several chemical problems can occur during the production of oil and gas through flow lines. This includes corrosion, scale deposition and gas hydrate plugging. Three separate chemicals may be needed to treat these issues. Kinetic hydrate inhibitors (KHIs) are used in cold oil or natural gas production flow lines to prevent the formation and plugging of the line with gas hydrates. They are often injected concomitantly with other production chemicals such as corrosion and scale inhibitors. KHIs are specific low molecular weight water-soluble polymers with amphiphilic groups formulated with synergists and solvents. However, many corrosion inhibitors (CIs) are antagonistic to the KHI polymer, severely reducing the KHI performance. It would be preferable and economic if the KHI also could act as a CI. We have explored the use of maleic-based copolymers as KHIs as well as their use as film-forming CIs. KHIs were tested using a natural gas mixture in high pressure rocking cells using the slow constant cooling test method. A terpolymer from reaction of vinyl acetate:maleic anhydride copolymer with cyclohexy lamine and 3,3-di-n-butylaminopropylamine (VA:MA-60% cHex-40% DBAPA), gave excellent performance as a KHI, better than the commercially available poly(N-vinyl caprolactam) (PVCap). CO2 corrosion inhibition was measured by Linear Polarization Resistance (LPR) in a 1 litre CO2 bubble test equipment using C1018 steel coupons. The new terpolymer gave good CO2 corrosion inhibition in 3.6 wt% brine, significantly better than PVCap, but not as good as a commercial imidazoline-based surfactant corrosion inhibitor. The terpolymer also showed good corrosion inhibition efficiency at high salinity conditions, (density 1.12 g/cm3). VA:MA-60% cHex-40% DBAPA shifted the open-circuit potential to more positive values and significantly decreased the corrosion rate.

The effect of mesoporosity in the reaction of vinyl acetate and isoamyl alcohol catalyzed by H-ZSM-5 zeolites based on natural Perlite

Diverse ZSM-5 zeolites having a dual porosity and different acidic properties have been prepared using natural Perlite as source of SiO2 and Al2O3. Two traditional methodologies were selected to generate hierarchical porosity in the parent ZSM-5: (1) soft templating approach to produce an ordered micro-mesoporous material (H-ZSM-5/MCM-41) and (2) different duration of alkaline treatment for the generation of intra-crystalline mesoporosity (H-ZSM-5-MS-x, x = 30, 60 and 90). Surface acidity and accessibility indexes were determined by adsorption of pyridine and 2,6-lutidine. The catalytic activity was evaluated in the reaction of vinyl acetate and isoamyl alcohol which produces isoamyl acetate and acetaldehyde diisoamyl acetal by transesterification and ketalization reactions, respectively. Isoamyl acetate has been selectively produced as a consequence of an adequate combination of Brønsted acidity and accessibility, thus H-ZSM-5/MCM-41 and H-ZSM-5-MS-60 presented enhanced catalytic activity and selectivity compared to the parent H-ZSM-5.

Composite ZSM-5/MCM-41 material obtained from a green resource and its enhanced catalytic performance in the reaction of vinyl acetate and isoamyl alcohol

Composite ZSM-5/MCM-41 material has been obtained by hydrothermal synthesis of alkali-treated ZSM-5 zeolite prepared from Expanded Perlite. A two-step procedure that avoids the traditional dual template synthesis strategy and involves the use of a natural resource as a raw material has been studied. The so-obtained micro-mesoporous material was characterized by X-ray diffraction, scanning and transmission electron microscopy, N2 adsorption-desorption measurements and thermal gravimetric analysis. Surface acidity studies of adsorbed pyridine and 2,6-lutidine demonstrated that mesopores in ZSM-5/MCM-41 have dramatically enhanced their accessibility property. For determination of the catalytic activity, the H-ZSM-5/MCM-41 and a microporous H-ZSM-5 were used as catalysts for the reaction between vinyl acetate and isoamyl alcohol at 90 °C. H-ZSM-5 suffers to rapid deposition of coke and acetaldehyde diisoamyl acetal was obtained as the primary product at the beginning of the reaction, while the H-ZSM-5/MCM-41 evidenced an enhanced conversion and improved selectivity towards isoamyl acetate.

Isoamyl acetate preparation from reaction of vinyl acetate and Isoamyl alcohol catalyzed by H-ZSM-5 zeolite: a kinetic study

Microporous H-ZSM-5 zeolite having good crystallinity and with the presence of Brønsted acid sites exclusively, was prepared by hydrothermal treatment of Expanded Perlite. The as-prepared H-ZSM-5 was used as heterogeneous catalyst for the reaction between vinyl acetate and isoamyl alcohol, as a greener alternative for the traditional preparation of isoamyl acetate. In this reaction, isoamyl acetate was generated by an acyl nucleophilic substitution mechanism, mediated by an acetylated zeolite complex, while acetaldehyde diisoamyl acetal has been produced as a secondary product due to a nucleophilic addition to acetaldehyde carbonyl carbon. The reaction was studied under different alcohol/ester molar ratio, supporting a second order kinetics when working under excess of one reactant. Moreover, an Eley-Rideal kinetic model has been suggested for a reaction mechanism of five steps, involving the ketalization of isoamyl alcohol and acetaldehyde as a parallel reaction that competes with transesterification.

Synthesis of 8-acetoxytetracyclo[4.4.12.5.17.10.01.6]dodec-3-ene and diesters of C1-C5 acids on its basis

Reaction of vinyl acetate with tricyclo[5.2.12.5.1.02.6]deca-3,8-diene in the presence of nano-TiO2 (20 nm) catalyst was studied. 8-Acetoxytetracyclo[4.4.12.5.17.10.01.6]dodec-3-ene was obtained in 88.5% yield. Addition of saturated monobasic acids C1-C5 to the obtained unsaturated monoester in the presence of the boron trifluoride etherate catalyst was investigated. Corresponding diesters were obtained in 68.1–93.0% yield. They can be used as the additives to synthetic oils and as components of perfumes.

The adsorption and reaction of vinyl acetate on Au/Pd(100) alloy surfaces

The surface chemistry of vinyl acetate monomer (VAM) is studied on Au/Pd(100) alloys as a function of alloy composition using temperature-programmed desorption and reflection–adsorption infrared spectroscopy. VAM adsorbs weakly on isolated palladium sites on the alloy with a heat of adsorption of ~55kJ/mol, with the plane of the VAM adsorbed close to parallel to the surface. The majority of the VAM adsorbed on isolated sites desorbs molecularly with only a small portion decomposing. At lower gold coverages (below ~0.5ML of gold), where palladium–palladium bridge sites are present, VAM binds to the surface in a distorted geometry via a rehybridized vinyl group. A larger proportion of this VAM decomposes and this reaction is initiated by CO bond scission in the VAM to form adsorbed acetate and vinyl species. The implication of this surface chemistry for VAM synthesis on Au/Pd(100) alloys is discussed.

1,3-Dipolar cycloaddition of N-[4-nitrophenyl]- C-[2-furyl] nitrilimine with some dipolarophiles: A combined experimental and theoretical study

Reaction of vinyl acetate ( 3), 2-propyne-1-ol ( 4) and styrene ( 5) as dipolarphiles with N-[4-nitrophenyl]- C-[2-furyl] nitrilimine which was generated in situ has been shown to afford 3-(furan-2-yl)-1-(4-nitrophenyl)-4,5-dihydro-1 H-pyrazol-5-yl acetate ( 6), (3-(furan-2-yl)-1-(4-nitrophenyl)-1 H-pyrazol-5-yl)methanol ( 8) and 3-(furan-2-yl)-1-(4-nitrophenyl)-5-phenyl-4,5-dihydro-1 H-pyrazole ( 10). Reactivity and regiochemistry of these reactions were investigated using DFT-based reactivity indexes.

Acetylation of Cellulose Nanowhiskers with Vinyl Acetate under Moderate Conditions

A novel and straightforward method for the surface acetylation of cellulose nanowhiskers by transesterification of vinyl acetate is proposed. The reaction of vinyl acetate with the hydroxyl groups of cellulose nanowhiskers obtained from cotton linters was examined with potassium carbonate as catalyst. Results indicate that during the first stage of the reaction, only the surface of the nanowhiskers was modified, while their dimensions and crystallinity remained unchanged. With increasing reaction time, diffusion mechanisms controlled the rate, leading to nanowhiskers with higher levels of acetylation, smaller dimensions, and lower crystallinity. In THF, a solvent of low polarity, the suspensions from modified nanowhiskers showed improved stability with increased acetylation.

Modelling the semi-batch vinyl acetate emulsion polymerization in a real-life industrial reactor

A detailed dynamic model of the polymerization reaction of vinyl acetate in a real-life industrial reactor is presented. With the recipe and the operating procedures observed in the factory as inputs, the model predicts with reasonable accuracy the final conversion, the average particle diameter, the solid content and the viscosity. The manual and semi-manual operations, and the decision process followed by the operator, are also modelled in order to replicate closely the process carried out in the factory. The model provides further insight into the reaction kinetics and allows us to make knowledge-based decisions. The model is intended to be used for the optimization of the policy of adding monomer in order to reduce the batch time.

The reaction of vinyl acetate with Pd(1 1 0) studied with TPD and molecular beams

The adsorption and reaction of vinyl acetate with the clean Pd(110) surface has been investigated using temperature programmed desorption and molecular beam reaction measurements. These show that, under low pressure conditions, the main reaction pathway above 400K is total dehydrogenation to yield hydrogen and carbon dioxide in the gas phase, and surface carbon. This occurs at a steady state, notwithstanding the fact that carbon is being deposited continuously onto the surface. The reaction continues because the vast majority of this carbon is lost from the surface to the bulk of the sample. Between about 320–380K the reaction profile is somewhat different; the molecule dissociates at the CH3COOCHCH2 bond, producing the most stable intermediate, the acetate, and the reaction stops after the build-up of adsorbed acetate and surface carbonaceous species. At ∼300K, the products are very similar to those for acetaldehyde adsorption (namely, methane, CO and some surface carbon), and they evolve in a non-steady state manner due to the build up of adsorbed CO on the surface. Thus the mechanism is dominated here by dissociation at the CH3COOCHCH2 bond, and formation of the acetyl intermediate. Consideration is given to the connection between these data and vinyl acetate synthesis.

The adsorption and reaction of vinyl acetate on Au/Pd(1 1 1) alloy surfaces

The adsorption of vinyl acetate is studied on Au/Pd(1 1 1) alloys as a function of alloy composition using temperature-programmed desorption and reflection–adsorption infrared spectroscopy. Vinyl acetate adsorbs weakly on gold sites on the alloy with a heat of adsorption of ∼55 kJ/mol, which is independent of the size of the gold ensembles. In contrast, adsorption of vinyl acetate on palladium sites is strongly affected by alloying. Vinyl acetate desorbs from isolated palladium sites on the alloy with an activation energy of ∼70 kJ/mol, close to that found on pure Pd(1 1 1). As the palladium coverage, and the number of palladium dimers and larger ensembles in the alloy increases, the heat of adsorption of vinyl acetate increases attaining a maximum of ∼80 kJ/mol at a gold coverage in the alloy of ∼0.5. However, in spite of the larger heat of adsorption on the alloy than on pure Pd(1 1 1), vinyl acetate does not undergo significant thermal decomposition on this alloy surface. This is ascribed to the formation of more distorted vinyl acetate in which the acetate group is more remote from the surface due to the rehybridization of the vinyl group. As the gold coverage decreases to ∼0.35 and lower, thermal decomposition products are found similar to those on Pd(1 1 1).

Kinetic Study of Radical Polymerization VIII. A Comprehensive Study of Solution Copolymerization of Vinyl Acetate and Methyl Acrylate by 1H‐NMR Spectroscopy

Radical copolymerization reaction of vinyl acetate (VA) and methyl acrylate (MA) was performed in a solution of benzene‐d6 using benzoyl peroxide (BPO) as the initiator at 60°C. Kinetic studies of this copolymerization reaction were investigated by on‐line 1H‐NMR spectroscopy. Individual monomer conversions vs. reaction time, which was followed by this technique, were used to calculate the overall monomer conversion, as well as the monomer mixture and the copolymer compositions as a function of time. Monomer reactivity ratios were calculated by various linear and nonlinear terminal models and also by simplified penultimate model with r 2(VA)=0 at low and medium/high conversions. Overall rate coefficient of copolymerization was calculated from the overall monomer conversion vs. time data and k p . k t −0.5 was then estimated. It was observed that k p . k t −0.5 increases with increasing the mole fraction of MA in the initial feed, indicating the increase in the polymerization rate with increasing MA concentration in the initial monomer mixture. The effect of mole fraction of MA in the initial monomer mixture on the drifts in the monomer mixture and copolymer compositions with reaction progress was also evaluated experimentally and theoretically.

Reactions of Vinyl Acetate and Vinyl Trifluoroacetate with Cationic Diimine Pd(II) and Ni(II) Alkyl Complexes: Identification of Problems Connected with Copolymerizations of These Monomers with Ethylene

Vinyl acetate (VA) and vinyl trifluoroacetate (VA(f)) react with [(NwedgeN)Pd(Me)(L)][X] (M = Pd, Ni, (NwedgeN) = N,N'-1,2-acenaphthylenediylidene bis(2,6-dimethyl aniline), Ar(f) = 3,5-trifluoromethyl phenyl, L = Ar(f)CN, Et2O; X = B(Ar(f))4-, SbF6-) to form pi-adducts 3 and 5 at -40 degrees C. Binding affinities relative to ethylene have been determined. Migratory insertion occurs in a 2,1 fashion (DeltaG++ = 19.4 kcal/mol, 0 degrees C for VA, and 17.4 kcal/mol, -40 degrees C for VA(f)) to yield five-membered chelate complexes [(NwedgeN)Pd(kappa2-CH(Et)(OC(O)-CH3))]+, 4, and [(NwedgeN)Pd(kappa2-CH(Et)(OC(O)CF3))]+, 6. When VA is added to [(NwedgeN)Ni(CH3)]+, an equilibrium mixture of an eta2 olefin complex, 8c, and a kappa-oxygen complex, 8o, results. Insertion occurs from the eta2 olefin complex, 8c (DeltaG++ = 15.5 kcal/mol, -51 degrees C), in both a 2,1 and a 1,2 fashion to generate a mixture of five- and six-membered chelates, 9(2,1) and 9(1,2). VA(f) inserts into the Ni-CH3 bond (-80 degrees C) to form a five-membered chelate with no detectable intermediate. Thermolysis of the Pd chelates results in beta-acetate elimination from 4 (DeltaG++ = 25.5 kcal/mol, 60 degrees C) and beta-trifluoroacetate elimination from 6 (DeltaG = 20.5 kcal/mol, 10 degrees C). The five-membered Ni chelate, 9(2,1), is quite stable at room temperature, but the six-membered chelate, 9(1,2), undergoes beta-elimination at -34 degrees C. Treatment of the OAc(f) containing Pd chelate 6 with ethylene results in complete opening to the pi-complex [(NwedgeN)Pd(kappa2-CH(Et)(OAc(f)))(CH2CH2)]+ (OAc(f) = OC(O)CF3), 18, while reaction of the OAc containing Pd chelate 4 with ethylene establishes an equilibrium between 4 and the open form 16, strongly favoring the closed chelate 4 (DeltaH = -4.1 kcal/mol, DeltaS = -23 eu, K = 0.009 M(-1) at 25 degrees C). The open chelates undergo migratory insertion at much slower rates relative to those of the simple (NwedgeN)Pd(CH3)(CH2CH2)+ analogue. These quantitative studies provide an explanation for the behavior of VA and VA(f) in attempted copolymerizations with ethylene.

Synthesis of Aromatic Vinyl Esters by Exchange Reaction Catalyzed with Pd(II)

Pd(II) catalyzed the exchange reaction of vinyl acetate with aromatic acids to produce the corresponding vinyl esters in good yields.

Hydroformylation of alkenes and alkynes using a heterobinuclear RhW catalyst

Hydroformylation reactions of a series of alkenes and alkynes have been carried out using the heteronuclear RhW catalyst, (CO) 4 W(μ-PPh 2) 2R hH(CO)(PPh 3) ( 1). The results of these reactions have been compared with corresponding reactions using [Rh(OAc) 2] 2 as catalyst. Catalysis of a reaction of styrene using 1 gave a very high yield of the branched chain aldehyde containing only a trace of the straight chain isomer. Reactions of the phosphinoalkene, Ph 2P(CH 2) 3CHCH 2 ( 7) and the corresponding alkyne, Ph 2P(CH 2) 3CCH ( 11) gave similar products using either catalyst system with the alkryne reaction being significantly slower. Reaction of the alkenyl dithiane, S(CH 2) 3SC HCH 2CHCH 2 ( 2), using the RhW catalyst ( 1) gave a higher ratio of linear to branched aldehydes (47 linear:53 branched) than the corresponding reaction using [Rh(OAc) 2] 2 (25 linear:75 branched). Reactions of vinyl acetate using 1 as catalyst gave a significant amount of linear aldehyde in contrast to reactions using [Rh(OAc) 2] 2 but reactions of allyl acetate gave similar products for both catalyst systems.

Structural Elucidation of Novel Derivatives of Pyranobisquinolines1H-NMR,13C-NMR and Mass Spectroscopic Study of (7H)-6,8-Dichloro-7-methyl-pyrano(3,2-c:5,6-c′)bisquinoline and (7H)-6,8-dichloro-7-methyl-pyrano (3,2-c:5,6-b′)bisquinoline

Abstract Elucidation of the structure of hitherto unknown novel pyranobisquinoline derivatives, (7H)-6,8-Dichloro-7-methyl -pyrano(3,2-c;5,6-c′)bisquinoline 5 and (7H)-6,8-Dichloro-7-methyl-pyrano(3,2-c:5,6-b′)bisquinoline 4 obtained as unexpected products1 in the Michael type reaction of vinylacetate on 4-hydroxyquinoline-2(lH)-one 1 by NMR methods is reported.

CH and NH bond activation in reactions of vinyl acetate, allyl cyanide, allylamine and other amines with (η‐C5H5)2Rh2(CO)(CF3C2CF3)

AbstractThere is activation of olefinic CH bonds when (η‐C5H5)2Rh2(CO)(CF3C2CF3) is treated with vinyl acetate or allyl cyanide. These reactions are initiated by exposure to sunlight. In the vinyl acetate reaction, each of the three vinylic CH bonds can be broken, but there is strong preference for cleavage at the substituted carbon. The products formed in these reactions are bisalkenyl complexes of the type (η‐C5H5)2Rh2{μ‐C(CF3)C(CF3)H}(μ‐CRCR′R″), and all isomers have been thoroughly characterized by NMR analysis. Similar reactions with allylamine and other amines (NH2R, NHMe2) occur in the dark and proceed by NH bond cleavage. Near‐quantitative amounts of the products, (η‐C5H5)Rh2{C(CF3)C(CF3)H}(C(O)NRR′) are isolated. Spectroscopic data indicate a bridging carboxamide ligand attached to the RhRh bond from oxygen and nitrogen donor sites. It is proposed that coordination of O or N to rhodium has a strong influence on all of the reactions studied.

Radical reactions of butyl mercaptan with vinyl and allyl acetates

The reactions of vinyl acetate and allyl acetate with butyl mercaptan in the presence of tert-butyl peroxide and Mn2(CO)10 lead to an adduct. Acetaldehyde, butyl thioacetate, and the dibutylmercaptal of acetaldehyde are also formed in the case of Mn2(CO)10.

Reactions of triads Se 8KOHDMSO, Se 8KOHDMSO, TeKOHHMPA with acetylenes

A new general approach to anionic transformations of acetylenes using superbasic media has been developed. It allows series of new reactions which are not undergone by acetylene under conventional conditions. The triads Se 8KOHdimethylsulfoxide (DMSO), Se 8KOHDMSO, TeKOH-hexamethyl-phosphorictriamide (HMPA) are proposed as new effective reagents for the preparation of unsaturated compounds of sulfur, selenium and tellerium. A series of reactions of acetylene with sulfur, selenium and tellerium proceeding in DMSO or HMPA in the presence of alkali and water at 80–120° leading to divinyl sulfide, divinyl selenide and divinyl teluride in 25–80% yields have been found. Thiophen, di-1-(1,3-butadienyl) sulfide, 1-vinyl-2-thiabicyclo[3.2.0]hept-3-ene, and dihydrothiophen have been obtained by the reaction of vinylacetate with sulfur. The reaction of vinylacetylene with selenium affords selenophen, di-1-(1,3-butadienyl) selenide, 1-vinyl-2-selenabicyclo[3.2.0]hept-3-ene, methyl (1-(1,3-butadienyl) sulfide, and methylthiomethyl 1-(1,4-butadienyl) selenide, vinyl 1-(1,3-butadienyl) sulfide, and methylthiomethyl 1-(1,3-butadienyl) selenide (the latter two with DMSO participation). The reaction of vinylacetate with tellerium gives mainly di-1-(1,3-butadienyl) telluride. A series of reactions between DMSO and selenium leading to dimethyl sulfide, dimethyl sulfoselenide, and methylthiomethyl selenide have been observed.

Mechanism of the reaction of vinyl acetate with phosphorus pentachloride

1. We have studied the reaction of vinyl acetate with PC15 in CCl4 and benzene with reactant ratios of 1∶1 and 1∶2. A 1∶2 adduct is formed only at low temperatures (∼0°C) in a solvent that does not solvate it. More forcing conditions or conditions under which phosphorus chlorides are solvated form a 1∶1 adduct; this spontaneously isomerizes to the cyclic product of addition of PCl5 to two donor sites of vinyl acetate, which is catalytically converted to [2-(α,α-dichloroethoxy)-2-chloroethyl]phosphonic dichloride.