MXPA01006035A - Process for the preparation of methyl p-vinylbenzoate and p-vinyl benzoic acid, and their use in latex compositions - Google Patents

Abstract

The present invention describes a process for the direct preparation of methyl p-vinylbenzoate from methyl p-formylbenzoate using keten in the presence of potassium acetate. The chief products obtained from the process are about a five to two ratio of methyl p-vinylbenzoate to p-carbomethoxycinnamic acid. The latter may be thermally decarboxylated, especially in the presence of copper powder, to produce additional quantities of methyl p-vinylbenzoate. Methyl p-vinylbenzoate may further undergo hydrolysis to form p-vinyl benzoic acid. Both methyl p-vinyl benzoate and p-vinyl benzoic acid may be polymerized with ethylenically unsaturated monomers to form useful latex compositions of the present invention.

Description

PROCESS FOR PREPARING METHYL P-VINYLBENZOATE AND P-VINYLBENZOIC ACID, AND THEIR USES IN LATEX COMPOSITIONS DESCRIPTION OF THE INVENTION Methyl p-vinylbenzoate has been prepared from a number of different synthetic trajectories over the years including the route more direct, the esterification of the same p-vinylbenzoic acid. However, even with the same direct esterification route, p-vinylbenzoic acid must first be prepared which may involve a number of synthetic sequences per se. In this way, a number of procedures have been developed that produce methyl p-vinylbenzoate without going through the acid first. The most direct route of olefination prior to this invention involves reacting methyl p-formylbenzoate under the boron-like conditions of ittig as described by Saki, et al in Tetrahedron, 52 (3), 915, 1996. However, the use Knochel's borylmethyl-reagent reagent does not itself lead to industrial reactions on a large scale; it is not economical to produce such quantities. Several olefinination pathways have been reported based on the Heck and Heck-related arylation of ethylene. One such method involving the palladium-catalyzed arylation of ethylene with methyl p-bromobenzoate is described by J. Kji, et al in J. Mol. Cat. A: Chem. 97, 73, 1995. A reaction involving methyl p-iodobenzoate by Rule and Fugue has been described in U.S. Patent 4,935,559 (assigned to Eastman Kodak). These latter reactions involve the use of halogenated compounds which must handle environmental issues. Other related chemistries involve methyl p-chlorosulfonylbenzoate as described by Kasahara, et al in Chem. Ind., 6, 192, 1989 and the arenodiazonium salts as developed by Kikukawa, et al in Bull. Chem. Soc. Jpn. , 52 (9), 2609, 1979. Still, other routes involve the oxidation of methyl p-ethylbenzoate to both methyl p-acetylbenzoate first as in British Patent 636,196 (assigned to Monsanto Chemical Company) and by Emerson, et al. in J. Am. Chem. Soc, 68, 674, 1946 or for methyl p-alpha-hydroxyethylbenzoate via the bromine derivative as described by Bergmann and Blumm in J. Org. Chem., 24, 549, 1959. Although these routes can produce large amounts of methyl p-vinylbenzoate, they also have several synthetic steps not mentioned which add production costs. Methyl p-vinylbenzoate has been prepared by several groups of individuals that are best suited for smaller and academic research laboratories. These processes include p-methylacetophenone described by Berg ann and Blum, or through both p-cyanoacetophenone or p-dibromobenzene, both described by Marvel and Overberger in J. Am. Chem. Soc., 67, 2250, 1945. The process of Direct olefination of an aromatic aldehyde with ketene in the presence of a potassium salt has been previously described by Hurd and Thomas in J. Am. Chem. Soc, 55, 275, 1933 and by Vittum in its PhD Thesis, Cornell University, 1933 The more detailed work describing this olefination which in many ways resembles Perkin's reaction has been described by Vittum. Most reactions are performed using benzaldehyde with ketone and some type of "catalyst" to prepare styrene and cinnamic acid, the primary reaction products of this reaction. It has been found that temperature variations over a relatively wide range have little impact on the yields and proportions of styrene and cinnamic acid. Additionally, a salt is needed in the course of the reaction and in particular, potassium salts are preferred. Previous studies involving substituted aromatic aldehydes such as meta and para-nitrobenzaldehyde, and anisaldehyde (para-methoxybenzaldehyde) suggest that direct olefination of the aldehyde group with ketene is not very feasible. In these cases, reaction products of meta- or para-nitrovinylbenzene (meta- or para-nitrostyrene) or para-methoxyvinyl-benzene (para-methoxystyrene) are not produced and only in the case of meta-nitrobenzaldehyde some of the corresponding cinnamic acid derivatives. In particular, the starting aldehyde is generally recovered or a bituminous residue is formed in the recovered starting aldehyde. The most substituted aldehydes in the Perkin reaction, especially those substituted in the para position, have a large negative influence on the proportion and reaction. Additionally, the type of substituent can have a great influence on the reactivity of the aldehyde in the Perkin reaction. Thus, there is a need for a process for the preparation of methyl p-vinylbenzoate from the reaction of methyl p-formylbenzoate with a ketene in the presence of a potassium salt. The present invention provides such a process. The present invention describes a direct method for the preparation of methyl p-vinylbenzoate by the reaction of methyl p-formylbenzoate with ketene in the presence of a potassium salt. The present method has the advantage of large-scale economic production of methyl p-vinylbenzoate. It is both unexpected and not obvious that methyl p-formylbenzoate with its methyl ester substituent can even react with ketene in the presence of a potassium salt to form methyl p-vinylbenzoate, based on previous work by others as discussed. previously . The above reaction also produces p-carbomethoxycinnamic acid as a coproduct with methyl p-vinylbenzoate. It has also been discovered that additional amounts of methyl p-vinylbenzoate can be prepared by thermal decarboxylation of p-carbomethoxycinnamic acid in the presence of copper powder. The methyl p-vinylbenzoate can also be reacted by hydrolysis to form the p-vinylbenzoic acid. It has been found that both methyl p-vinylbenzoate and p-vinylbenzoic acid are monomers useful for the emulsion polymerization with other ethylenically unsaturated monomers to form latex compositions. Both the latex compositions and the monomers of the present invention can be used in a number of end-use applications, such as coatings, photoresists and as a partial replacement of styrene in unsaturated polyesters. In the present processes have been discovered for the preparation of methyl p-vinylbenzoate (MVB) from methyl p-formylbenzoate. More specifically, methyl p-formylbenzoate reacts with ketene in the presence of a potassium salt, such as potassium acetate, to form methyl p-vinylbenzoate and p-carbomethoxycinnamic acid. The source of generation of ketene used can be from the pyrolysis of acetone; however, any method of generating ketene known in the art can be used. The ketene can also be obtained by pyrolysis of, for example, diketene, acetic anhydride and acetic acid. The relative amount of ketene to methyl p-formylbenzoate used can vary from less than 10 percent to more than 500 percent depending on the conditions used, desired conversion ratios, and desired selectivity. Potassium salts suitable for initiation of the reaction include, but are not limited to, potassium acetate, potassium carbonate, potassium benzoate, potassium cinnamate, and potassium propionate. When an equivalent of the potassium salt is used, based on the aldehyde, styrene is hardly produced; while 15-20 percent of p-carbomethoxycinnamic acid is produced. The level of potassium salt used can vary from less than one mole percent to more than 100 mole percent based on methyl p-formylbenzoate. It is preferred that the molar ratio of the potassium salt to methyl p-formylbenzoate be less than 0.50. It is even more preferred that the molar ratio of potassium salt to methyl p-formylbenzoate be less than 0.20.

At low temperatures, it may be necessary to dissolve the methyl p-formylbenzoate in a suitable solvent. Useful solvents for the reaction include aliphatic and cycloaliphatic hydrocarbons; aromatic hydrocarbons; cyclic and acyclic ethers, esters and ketones. The amount of the solvent can be as much as necessary to prepare a 0.001 molar solution. Preferably, the methyl p-formylbenzoate is dissolved in sufficient solvent to prepare a 0.1 to 10.0 molar solution. At higher temperatures, solvents may not be necessary to carry out the reaction. In general terms, the process of the present invention involves reacting a mixture of aromatic aldehyde and potassium salt with ketene. More specifically, the aromatic aldehyde is methyl p-formylbenzoate. The mixture of aromatic aldehyde and potassium salt is generally homogeneous, unless a particular potassium salt is soluble in methyl p-formylbenzoate, in which case it may be homogeneous. At lower temperatures, methyl p-formylbenzoate is a solid so it is preferable to add a solvent before adding the potassium salt. The ketene can be bubbled into the reaction vessel as a gas, or it can be condensed first and added as a liquid. The reaction can be carried out at temperatures in the range of about 0 ° C to 200 ° C, although it is preferable that it be between about 20 ° C and about 80 ° C at low pressures (up to 5 atmospheres). The reaction pressure can be from less than one atmosphere to more than 100 atmospheres using appropriate autoclave equipment to withstand the higher pressures. Since methyl p-formylbenzoate melts at about 62 ° C, reactions carried out above these temperatures can be carried out without the addition of solvents. Generally, as soon as the reaction temperature is increased, the reaction time is shortened to reduce the potential polymerization of the desired products. Suitable reaction times are generally up to about 100 hours at temperatures up to about 30 ° C. At temperatures greater than 40 ° C, an antioxidant and / or polymerization inhibitor may be added in concentrations up to about five percent. Suitable antioxidants include, but are not limited to hydroquinone, t-bu ilhydroquinone, hindered phenols, hydroquinone ethoxy ethers and butylated hydroxy toluene. The main products obtained from the process of the present invention are approximately a five to two ratio of methyl p-vinylbenzoate to acid. p-carbomethoxycinnamic. The latter can also be subjected to thermal decarboxylation, in the presence of copper powder, to produce additional amounts of methyl p-vinylbenzoate, using known decarboxylation conditions. Suitable decarboxylation conditions include, but are not limited to, the range from about 150 ° C to about 350 ° C; pressures of up to approximately 100 atmospheres, and times of up to approximately 24 hours. In addition, the process can be carried out in the presence of an antioxidant or other polymerization inhibitor as described above. Another embodiment of the present invention is a process for the preparation of p-vinylbenzoic acid by reacting methyl p-formylbenzoate and ketene, in the presence of a potassium salt, to form methyl p-vinylbenzoate; followed by hydrolysis of methyl p-vinylbenzoate to p-vinylbenzoic acid. The hydrolysis of the esters can typically be catalyzed by an acid or a base. When hydrolysis of the esters occurs under basic conditions such as sodium hydroxide, hydrolysis is referred to as saponification. The saponification provides the salt of the carboxylic acid which can then be further reacted with an acid, such as a mineral acid, to provide the carboxylic acid. Hydrolysis of methyl p-vinylbenzoate (PMVB) to p-vinylbenzoic acid (VBA) may occur by saponification of methyl p-vinylbenzoate with aqueous sodium hydroxide, separation of organic impurities by phase separation, followed by addition of aqueous hydrochloric acid to provide p-vinylbenzoic acid (VBA) Methyl p-vinylbenzoate can be used (MVB) and p-vinylbenzoic acid (VBA) of the present invention as monomers in a free radical emulsion polymerization to form latex polymers, using conventional emulsion polymerization techniques. Other monomers that can be used in combination with the monomers of the present invention to form the latex polymers can be broadly characterized as ethylenically unsaturated monomers. These include, but are not limited to, non-acidic vinyl monomers, vinyl acidic monomers and / or mixtures thereof. The latex polymers of the invention can be copolymers of non-acidic vinyl monomers and acidic monomers, mixtures thereof and their derivatives. The latex polymers of the invention can also be homopolymers of ethylenically unsaturated monomers. Suitable non-acidic vinyl monomers that can be used to prepare the latex polymer include, but are not limited to, acetoacetoxyethyl methacrylate, acetoacetoxyethyl acrylate, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, acrylate. butyl, butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl acrylate, isoprene, octyl acrylate, octyl methacrylate, iso-octyl acrylate, methacrylate of iso-octyl, trimethylolpropyl triacrylate, styrene, α-methylstyrene, glycidyl methacrylate, carbodiimide methacrylate, C.sub.1 alkyl crotonates. -C? 8, di-n-butyl maleate, a or β-vinylnane, di-octylmaleate, allyl methacrylate, di-allyl maleate, di-allyl malonate, methoxybutenyl methacrylate, isobornyl methacrylate, hydroxybutenyl methacrylate, ( met) hydroxyethyl acrylate, hydroxypropyl (meth) acrylate, acrylonitrile, vinyl chloride, vinylidene chloride, vipyl acetate, vinylethylene carbonate, epoxybutene, 3,4-dihydroxybulen, (meth) hydroxyethyl acrylate, methacrylamide, acrylamide, butylacrylamide, ethylacrylamide, butadiene, vinyl ester monomers, vinyl (meth) acrylates, isopropenyl (meth) acrylate, cycloaliphatic epoxy (meth) acrylates, ethylformamide, 4-vinyl-1 , 3-dioxolan-2-one, 2, 2-dimethyl-4-vinyl-l, 3-dioxolane, and 3,4-di-acetoxy-1-butene or a mixture thereof. Suitable non-acidic vinyl monomers are described in The Brandon Associates, 2nd Edition, 1992 Merrimack, New Hampshire, and in Polymers and Monomers, the 1966-1997 catalog of Polyscience, Inc., Warrington, Pennsylvania, USA Vinyl Monomers acids which may be used to prepare the latex polymer include, but are not limited to, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, monovinyl adipate and mixtures thereof .Preferred useful monomers for preparing latex polymers ( (co) polymers are ethylenically unsaturated monomers including, but not limited to acrylates, methacrylates, vinylesters, styrene, styrene derivatives, vinyl chloride, vinylidene chloride, acrylonitrile, isoprene and butadiene In a more preferred embodiment, the polymer of latex comprises (co) polymers made of 2-ethylhexyl acrylate monomers, styrene, butyl acrylate, butyl methacrylate, acrylate ethyl, methyl methacrylate, butadiene and isoprene. In a preferred embodiment, the latex polymer of the present invention has a weight average molecular weight (Mw) in the range of about 10,000 to about 2,000,000 as determined by gel permeation chromatography (GPC); more preferably the weight average molecular weight is in the range of about 50,000 to about 1,000,000. In one embodiment, the glass transition temperature (g) of the latex polymer is in the range of about -50 ° C to about 150 ° C. The latex compositions of the present invention can be characterized as latexes stabilized in a continuous phase by the addition of a diol component. A stable latex is defined for the purposes of this invention as one in which the parti are colloidally stable, ie, the latex particles remain dispersed in the continuous phase for long periods of time, such as 24 hours, preferably 48 hours, weeks even more preferably, several months. The latex polymer particles generally have a spherical conformation and may have a covered core polymer or a coreless polymer. When a coated core polymer is used, the polymers can be prepared in a core / shell form by stacking the addition monomer. For example, the monomer composition fed from the polymerization can be changed in the course of the reaction in an abrupt manner, resulting in a different core and shell portion for the polymer. Preferred monomers useful for preparing coated core latex polymers / (co) are ethylenically unsaturated monomers including, but not limited to, acrylates, methacrylates, vinylesters, styrene, styrene derivatives, vinyl chloride, vinylidene chloride, acrylonitrile , isoprene and butadiene. In a more preferred embodiment, the coated core latex polymer comprises (co) polymers prepared from 2-ethylhexyl acrylate monomers, styrene, butyl acrylate, butyl methacrylate, ethyl acrylate, methyl methacrylate, butadiene and isoprene. . The core / shell polymer particles can also be prepared in a multi-stratification form, a walnut shell, an acorn form, or a raspberry shape. In these type particles, the core portions may comprise from about 20 to about 80 percent of the total weight of the particle and the shell portion may comprise from about 80 to about 20 percent of the total weight volume of the particle. In a preferred embodiment, the chain transfer agents can be used in the emulsion polymerization. Typical chain transfer agents are those known in the art. Chain transfer agents that can be used in the emulsion polymerization reaction to form the diol latex compositions include, but are not limited to, butyl mercaptan, dodecyl mercaptan, mercaptop spic acid, 2-ethylhexyl-3-mercaptopropionate, n- butyl-3-mercaptopropionate, octylmercaptan, isodecylmercaptan, octadecylmercaptan, mercaptoacetic acid, allyl mercaptopropionate, allyl mercaptoacetate, crotyl mercaptopropionate, crotyl mercaptoacetate, and the reactive chain transfer agents described in U.S. Pat. No. 5,247,040, incorporated herein by reference. Preferably the chain transfer agent is selected from mercaptans and various alkyl halides, including but not limited to carbon tetrachloride.; more preferably the chain transfer agent is 2-ethylhex: J.l-3-mercaptopropionate. The chain transfer agents can be added in amounts of 0 to 2 parts per hundred monomer (pcm), more preferably 0 to 0.5 pcm. The latex polymers of the invention can be crosslinked or non-crosslinked. When crosslinked, suitable crosslinking agents include multifunctional unsaturated compounds including, but not limited to, divinylbenzene, allyl methacrylate, allyl acrylate, multifunctional acrylates, and mixtures thereof. Suitable multifunctional acrylates include, but are not limited to, ethylenediol dimethacrylate, ethylenediol diacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritoltetraacrylate, and mixtures thereof. The amount of monomer crosslinking in the emulsion polymerization can be controlled to vary the gel fraction of the latex from about 20 to about 100 percent. The gel fraction is the amount that will not dissolve in a good solvent. The latex particles can be functionalized by including monomers with pendant functional groups. Functional groups that can be incorporated into the latex particle include, but are not limited to, epoxy groups, acetoacetoxy groups, carbonate groups, hydroxyl groups, amine groups, isocyanate groups, amide groups, and mixtures thereof. Functional groups may be derivatives of a variety of monomers, including, but not limited to, glycidyl methacrylate, acetoacetoxyethyl methacrylate, vinylethylene carbonate, hydroxyethyl methacrylate, t-butylaminoethyl methacrylate, dimethylamino methacrylate, isocyanate m -isopropenyl-alpha, alpha-dimethylbenzyl, acrylamide and n-methylolacrylamide. The addition of functional groups allows an additional reaction of the polymer after the synthesis of the latex. The initiators can also be used in the emulsion polymerization to form the latex compositions, including, but not limited to, salts of persulfates, water-soluble organic peroxides and initiators of the azo type. Preferred initiators include, but are not limited to, hydrogen peroxide, ammonium or potassium peroxydisulfate, dibenzoyl peroxide, lauryl peroxide, di-tertiary butyl peroxide, 2,2'-azobisisobutyronitrile, t-butyl hydroperoxide, benzoyl peroxide, and mixtures thereof. Also useful are the redox initiation systems (initiation of oxidation reduction) such as the iron-catalyzed reaction of t-butyl hydroperoxide with isoascorbic acid. It is preferable not to use initiators capable of generating a strong acid as a secondary product. This avoids possible side reactions of the diol component of the solvent in the acid. The initiators can be added in amounts of 0.1 to 2 cfm, more preferably 0.3 to 0.8 cfm. The reducing agents can also be used in the emulsion polymerization. Suitable reducing agents are those which increase the polymerization rate and include, for example, sodium bisulfite, sodium hydrosulfite, sodium formaldehyde sulfoxylate, ascorbic acid, isoascorbic acid and mixtures thereof. If a reducing agent is introduced into the emulsion polymerization, it is preferably added in an amount of 0.1 to 2 cfm, more preferably 0.3 to 0.8 cfm. It is preferable to feed the reducing agent into the reactor over a period of time. Damping agents can also be used in the emulsion polymerization to control the pH of the reaction. Suitable damping agents include, but are not limited to, the ammonium and sodium salts of carbonates and bicarbonates. It is preferred that the buffering agents be included when using acid-generating initiators, including, but not limited to, the persulfate salts. The polymerization catalysts can also be used in the emulsion polymerization. Polymerization catalysts are those compounds that increase the polymerization rate and which, in combination with the reducing agents described above, can promote the decomposition of the polymerization initiator under the reaction conditions. Suitable catalysts include, but are not limited to, transition metal compounds such as, for example, ferrous sulfate heptahydrate, ferrous chloride, cupric sulfate, cupric chloride, cobalt acetate, cobaltous sulfate, and mixtures thereof. This invention may further be illustrated by the following examples of preferred embodiments of the same, although it will be understood that these examples are included merely for purposes of illustration and are not intended to limit the scope of the invention unless specifically indicated otherwise. thing. E ploses The test materials and procedures used for the results shown herein are as follows: Molecular weight distributions are determined by gel permeation chromatography (CPG). Solutions are prepared by dissolving about 4 mg of polymer in a 30/70 by weight solution of hexafluoroisopropanol / methylene chloride containing 10% by volume of toluene as a flow ratio marker. The system is calibrated using a series of narrow molecular weight polystyrene standards. Molecular weights are reported in absolute molecular weight values determined from a group of Mark-Houwink constants that relate Pet to polystyrene. The thermal transitions are determined by differential scanning calorimetry (DSC) in DSC DuPont instruments 2200. The DSC experiments are performed using a sweep ratio of 20 ° C / min. After the sample is heated above its melting temperature and stops rapidly below its glass transition temperature. The particle size of the polymer latex dispersions is measured by the light scattering method using the ultraparticle analyzer (UPA) called Microtrac from Leeds and Northrup Instruments. Example 1: Preparation of methyl p-vinylbenzoate (MVB) To a three-necked round bottom flask equipped with a top stirrer, addition funnel, and a nitrogen inlet sodium hydride as a 60% dispersion ( 58.5 g, 1.46 moles). The sodium hydride is washed with THF (300 ml) then fresh THF (200 ml) is added. Methyltriphenyl-phosphonium bromide (500.1 g, 1.40 mol) is added to the well-stirred suspension at 35 minutes in room temperature. After a further 40 minutes of stirring, a solution of methyl p-formylbenzoate (218.9 g, 1.33 moles) in THF (600 ml) is added over 20-25 minutes. The mixture is then stirred at room temperature overnight for a total of 18 hours. The mixture is then filtered and the filtrate is concentrated in vacuo. The residue is then treated with a 50% solution of ethyl acetate in hexanes (1400 ml) and filtered again. The filtrate is then concentrated in vacuo and placed on a large chromatography column (1400 ml of silica gel 60 packed in 37-60 mesh with a 5 percent solution of ethyl acetate in hexanes) and eluted with a solution at 5 percent ethyl acetate in hexanes. Combine the desired fractions and concentrate in vacuo to provide 180.67 g (83.5 percent) of oil that solidifies slowly to a white waxy solid. Proton NMR (Gemini 300 MHz in deuterochloroform): delta 7.98 (2H), 6.72 (1H), 5.82 (1H), 5.37 (1H), 3.88 (3H), the FDMS confirms a mass of 162. Example 2: Preparation of methyl p-vinylbenzoate (MVB) The acetone (1250 ml) is charged to a 2 1 round-bottom flask through an addition funnel as shown in Figure 1. It is loaded into a round bottom flask, of three necks, 2 liters equipped with a stir bar, methyl p-formylbenzoate (164.16 g, 1.0 mole), potassium acetate (9.82 g, 0.10 mole), and THF (500 ml). It is loaded into a three-necked round bottom flask, one liter methanol (700 ml) for use as a scrubber for unreacted ketene which can pass through the reaction flask. Once the flasks are loaded, the system is flushed with nitrogen for several hours before the flasks containing acetone are heated to bring it to gentle reflux. Once it is believed that the system is purged of air, the metallic filament is heated to an opaque red color (the ketene generating device is available from Ace Glass while other necessary equipment is available from both Ace Glass and Lab Glass) and the generated ketene (the conversion is not determined) is bubbled into the reaction flask. There may be a potential danger if the bubble tube in the reaction flask is inserted into the reaction mixture before the ketene is generated. The solid potassium salt in the reaction flask can plug the tube creating pressure from the ketene generator to the reaction flask. In this way, the ketene is first generated by creating a positive pressure in the line, then the bubble tube can be inserted into the reaction mixture. The acetone is continued to be pyrolyzed until a sufficient conversion of the methyl p-formylbenzoate is observed. Approximately 10 hours of acetone pyrolysis is required to achieve an 85% conversion of methyl p-formylbenzoate with a selectivity of 67 percent for methyl-vinylbenzoate and approximately 26 percent of what is believed to be p-carbomethoxycinnamic acid as it is determined by its retention time in gas chromatography with a p-carbomethoxycinnamic acid prepared in an alternative form. A sample of the mixture prepared above is distilled in vacuum in four fractions. Each of the four fractions contains methyl p-vinylbenzoate and the last two fractions contain some unreacted methyl p-formylbenzoate. Of the 72.6 g of recovered distillate, 58.3 g are methyl p-vinylbenzoate and 6.8 g of methyl p-formylbenzoate. Example 3: Preparation of p-vinylbenzoic acid (VBA) To a well stirred solution of methyl p-vinylbenzoate (36.0 g, 0.222 mol) in THF (200 ml) is added to a solution of sodium hydroxide (17.78 g, 0.444 mol) in water (200 ml) in room temperature. After stirring overnight, water (100 ml), THF (150 ml), and ethyl ether (200 ml) are added and the phases are separated. The aqueous phase is acidified with a solution of concentrated hydrochloric acid (41 ml) in water (90 ml) then extracted three times with THF (500-600 ml each). The last combined organic extracts are dried over anhydrous magnesium sulfate, filtered and concentrated in vacuo to provide 32. 7 g (99.5 percent) of white solids. Nmr of protons (Ge ini model 300 MHz) in deuterochloroform: delta 8.08 (2H), 7.50 (2H), 6.78 (1H), 5.90 (1H), 5.41 (1H). Example 4 Preparation of p-carbomethoxycinnamic acid To a three-neck three-necked round bottom flask equipped with an overhead stirrer, a condenser, and a nitrogen / thermocouple unit, methyl p-formylbenzoate (82.08 g, 0.50 moles) is added. ), malonic acid (104.06 g, 1.00 mol) and pyridine (200 ml). Stirring is initiated followed by heating at 50 ° C for 75 minutes. At the same time, a dimensionable amount of solids have been formed and piperidine (7.5 ml, 0.076 mol) is added to this method and the temperature is increased to 80 ° C. After another hour at 80 ° C, the temperature is increased to 115 ° C. After another 2.5 hours at this temperature, the heating is stopped and allowed to cool before pouring into water (2 liters). Concentrated HCl (250-300 ml) is carefully added to the aqueous mixture until the mixture becomes acidic. The mixture is filtered, and the solids are washed with fresh water (1 liter) before they are dried by suction. A yield of 96.83 g (93.9 percent) of white solids is obtained. Nmr of protons (DMS0-d6) delta: 7.95 (2H, d); 7.80 (2H, d); 7.60 (1H, d); 6.62 (1H, d); 3.82 (3H, s). Example 5: Preparation of methyl p-vinylbenzoate (MVB) by decarboxylation of p-carbomethoxycinnamic acid To a 300 ml three-necked round bottom flask equipped with an overhead stirrer, a nitrogen / thermocouple unit, and an adapter is added formed in a semicircle with a round bottom flask attached (to collect the distillate), p-carbomethoxycinnamic acid (99.93 g, 0.485 moles (and copper powder (1.02 g).) The mixture is heated at 258 ° C for about 30 minutes while 5-10 ml of distillate is collected, the temperature is increased to 290 ° C for 15-20 minutes while a small amount of additional distillate is collected, the mixture is allowed to cool slowly, then carefully emptied into a 1 liter flask that contains a 4 to 1 mixture of hexanes to ethyl acetate (800 ml combined) Immediately, the grayish green solids formed after the addition and mixing are filtered. The mixture is about 70 percent p-carbomethoxycinnamic acid and about 27 percent methyl p-vinylbenzoate. The solids are washed with fresh ethyl acetate, then filtered. This filtrate contains about 59 percent p-carbomethoxycinnamic acid and about 41 percent methyl p-vinylbenzoate. The distillate harvested is diluted with ethyl acetate which causes two layers to form. Gas chromatography of the lower layer shows a mixture of 37% p-carbomethoxycinnamic acid and 63% methyl p-vinylbenzoate. Gas chromatography of the upper layer contains 10 percent p-carbomethoxycinnamic acid, 27 percent unidentified material and 49 percent methyl p-vinylbenzoate. Example 6: Preparation of latex. Comparative Example This example illustrates the formation of a latex polymer by using a widely used, commercially available methyl methacrylate (MMA) monomer by free radical polymerization. It is added to a 1-liter jacketed reaction vessel equipped with a condenser, nitrogen purge, and an agitator, 150 g of water containing 5.0 g of Abex EP-100 surfactant. The contents of the reactor are heated to 70 ° C. In a separate flask, 100.0 g of MMA are weighed. In a separate vessel, 0.5 g of ammonium persulfate, used as an initiator, is dissolved in 50 g of distilled water. The monomer and the initiator are pumped separately to the hot reactor for a period of 2.0-3.0 hours. After a few minutes, the appearance of the reactor changes color to a bluish-white tint that indicates the formation of small particles. The remaining monomer mixture and the initiator are continuously fed to the reactor. After all the monomer mixture is added, the reaction is maintained at 70 ° C for an additional hour at which point the reactor is cooled to room temperature. The resulting latex is filtered through a disk cloth. The latex is evaluated for solids content using a Computrac and an oven at 80 ° C. The latex contains 38.24% solids by Computrac and 38.58% solids by kiln drying method. The tg of the dry latex polymer is 130.13 ° C. The molecular weight (Pm) of the latex polymer is 1,586,253 and (Pm) is 8,768 with polydispersity of 180.9. The formation of MMA polymer by proton NMR is confirmed. The average particle size of the latex dispersions, as measured by the light diffusion method, is 121.5 nm. The acid number of the acrylic copolymer is 7.5 mg / g. Example 7: Polymerization of latex emulsion (MMA / MVB) This example illustrates the process for preparing acrylic latexes using methyl methacrylate (MMA) and methyl p-vinylbenzoate (MVB). The methyl p-vinylbenzoate used is from Example 1. 1.50 g of MVB is dissolved in 50 g of the MMA monomer using mixing devices known in the art. To a 1 liter jacketed reaction vessel equipped with a condenser, a nitrogen purge, and a stirrer, 150 g of water containing 5.0 g of Abex EP-100 surfactant is added. The contents of the reactor are heated to 70 ° C. In a separate 500 ml flask, a monomer mixture containing 50.0 g of MMA and 50.0 g of MVB is prepared. In a separate vessel, 0.5 g of ammonium persulfate, used as an initiator, is dissolved in 50 g of distilled water. The monomer mixture and the initiator are pumped separately to the hot reactor in a period of 2.0-3.0 hours. After a few minutes, the appearance of the reactor changes from clear to a bluish-white tint that indicates the formation of small particles. The remaining monomer mixture and the initiator are fed continuously into the reactor. After the monomer mixture is added, the reaction is maintained at 70 ° C for an additional hour at which point the reactor is cooled to room temperature. The resulting latex is filtered through a multi-layered disc cloth. The latex is evaluated for solids content using a computrac and an oven at 80 ° C. Latex contains 31.25% solids by Computrac and 31.88% solids by an oven drying method. The Tg of the dry latex polymer is 126. | ° C. The molecular weight (Pm) of the latex polymer is 1,136,646 and (Pm) is 41,299 with polydispersity of 27,522. The formation of the MMA / MVB copolymer is also confirmed by proton NMR. The average particle size of the latex dispersions as measured by light microscopy is 110.3 nm. The acid number of the acrylic copolymer is 1.7 mg / g. Example 8: Polymerization of játex emulsion (BA / MVB) Example 7 is repeated with the exception that the butyl acrylate monomer (BA) is used in place of the MMA monomer to prepare latex. The resulting latex is filtered through a multi-layered disc cloth. The latex is evaluated for solids content using a computrac and an oven at 80.0 ° C. The material contains 29.54% solids by Computrac and 30.52% solids by a kiln drying method. The Tg of the dry latex polymer is 58.54 ° C. The molecular weight (Pm) of the latex polymer is 1,197, 992 and the (Nm) is 270, 130 with the polydispersity of 4,435. The BA / MVB copolymer is also confirmed by proton NMR. The average particle size of the latex dispersions as measured by lμz microscopy is 63.0 nm. The acid number of the acrylic copolymer is 1.07 mg / g. Example 9: Polymerization of latex emulsion (BA / MVB) Example 8 is repeated under identical conditions to determine the reproducibility of the process and the properties of the acrylic latexes. The resulting latex is filtered through a multi-layered disc cloth. The latex is evaluated for solids content using a computrac and an oven at 80.0 ° C. The material contains 32.98% solids by Computrac and 33.8% solids by a kiln drying method. The Tg of the dry latex polymer is 57.11 ° C. The molecular weight (Pm) of the latex polymer is 1,609,284 and the (Nm) is 356,346 with the polydispersity of 4,516. The formation of the BA / MVB copolymer is also confirmed by NMr of protons. The average particle size of the latex dispersions as measured by light microscopy is 76.9 nm. The acid number of the acrylic copolymer is 1.34 mg / g. Example 10: Polymerization of latex emulsion (VBA / Styrene / 2-HEMA) This example illustrates the process for preparing acrylic latexes using p-vinylbenzoic acid (VBA). The p-vinylbenzoic acid used is from Example 3. The VBA (5.0 g) is dissolved in a monomer mixture in a 50/50 ratio of styrene and 2-hydroxyethyl methacrylate (2-HEMA) using devices known in the art. To a 1 liter jacketed reaction vessel equipped with a condenser, a nitrogen purge, a stirrer, 150 g of water containing 5.0 g of Abex EP-100 surfactant is added. The contents of the reactor are heated to 70 ° C. In a separate 500 ml flask, a monomer mixture is prepared containing 47.5 g of styrene, 47.5 g of 2-HEMA and 5.0 g of VBA. In a separate container, 0.5 g of ammonium persulfate, used as an initiator in 50 g of distilled water, is dissolved. The monomer mixture and the initiator are pumped separately to the hot reactor in a period of 2.0-3.0 hours. After a few minutes, the appearance of the reactor changes from clear to blue-white dye indicating the formation of small particles. The remaining monomer mixture and the initiator are fed continuously into the reactor. After all the monomer mixture is added, the reaction is maintained at 70 ° C for an additional hour at which point the reactor is cooled to room temperature. The resulting latex is filtered through a multi-layered disc cloth. The latex is evaluated for solids content using a computrac and an oven at 80 ° C. The latex contains 35.26% solids by Computrac and 36.05% solids by the kiln drying method. The Tg of the dry latex polymer is 116.57 ° C. The molecular weight (Pm) of the latex polymer is 213,807 and the (Nm) is 1,395 with polydispersity of 165.71. The material does not dissolve completely in the solvents for analysis indicating the cross-linking of the functional group in the latex polymer. The average particle size of the latex dispersions as measured by light microscopy is 141.5 nm. The acid number of the acrylic copolymer is 5.27 m! ~ F / cf and the hydroxyl number is 193.36. Example 11: Polymerization of latex emulsion (VBA) / Styrene / 2-HEMA) Example 10 is repeated with the exception that the latexes are dried at room temperature instead of 80 ° C. The molecular weight (Pm) of the latex polymer is 589,548 and the (Nm) is 53,792 with the polydispersity of 10.96. The number average molecular weight of the acrylic polymer is higher than that of the air dried sample compared to the same dry latex at 80 ° C, indicating low polydispersity of the latex polymer. Example 12: Polymerization of latex emulsion (VBA / Styrene / 2-HEMA) Example 10 is repeated with the exception that different amounts of styrene, 2-HEMA and VBA monomers are used in latex formation. The p-vinylbenzoic acid used is of Example 3. The VBA (2.5 g) is dissolved in the mixture of styrene monomers and 2-hydroxyethyl methacrylate (2-HEMA) using the mixing devices known in the art. To a 1 liter jacketed reaction vessel equipped with a condenser, a nitrogen purge, and a stirrer, 150 g of water containing 5.0 g of Abex EP-100 surfactant is added. The contents of the reactor are heated to 70 ° C. It is prepared in a 500 ml flask, a monomer mixture containing 95.0 g of styrene, 2.5 g of 2-HEMa and 2.5 g of VBA. In a separate vessel, 0.5 g of ammonium persulfate, used as an initiator, is dissolved in 50 g of distilled water. The monomer mixture and the initiator are pumped separately to the hot reactor in a period of 2.0-3.0 hours. After a few minutes, the appearance of the clear reactor changes to a blue-white dye indicating the formation of small particles. The remaining monomer mixture and the initiator are fed continuously into the reactor. After the entire monomer mixture is added, the reaction is maintained at 70 ° C for an additional hour at which point the reactor is cooled to room temperature. The resulting latex is filtered through a multi-layered disc cloth. The latex is evaluated for solids content using a computrac and an oven at 80 ° C. The latex contains 34.25% solids by Computrac and 34.50% solids by the method of drying in an oven. The Tg of the dry latex polymer is 114.78 ° C. The molecular weight (p) of the latex polymer is 1,247,729 and the (Nm) is 3,628 with the polydispersity of 343.90. The material does not dissolve completely in the solvents for analysis indicating the cross-linking of the functional group in the latex polymer. The average particle size of the latex dispersions as measured by light microscopy is 81.0 nm. The acid number of the acrylic copolymer is 3.98 mg / g and the hydroxyl number is 20.67. Example 13: Polymerization of latex emulsion (VBA / Styrene / 2 -HEMA) Example 12 is repeated with the exception that the latexes are dried at room temperature instead of 80 ° C. The molecular weight (Pm) of the latex polymer is 1,064,073 and the (Nm) is 112,616 with the polydispersity of 9.45. The number average molecular weight of the acrylic polymer is higher than that of the dried sample in air as compared to the same dry latex at 80 ° C, indicating low polydispersity of the latex polymer. In the specification, typical preferred embodiments of the invention are described and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limiting, the scope of the invention as set forth in the following claims.

Claims (26)

1. CLAIMS 1. A process for the preparation of methyl p-vinylbenzoate characterized in that it comprises reacting methyl p-formylbenzoate and ketene in the presence of a potassium salt to form methyl p-vinylbenzoate.
2. 2. The process according to claim 1, characterized in that the potassium salt is selected from the group consisting of potassium acetate, potassium carbonate, potassium benzoate, potassium cinnamate, and potassium propionate.
3. 3. The process according to claim 1, characterized in that the molar ratio of the potassium salt to methyl p-formylbenzoate is better than 0.50.
4. 4. The process according to claim 1, characterized in that the molar ratio of potassium salt to methyl p-formylbenzoate is less than 0.20.
5. 5. The process according to claim 1, characterized in that the source of cetepo is selected from the group consisting of acetone, acetic anhydride and acetic acid.
6. 6. The process according to claim 1, characterized in that it also comprises the addition of a solvent.
7. 7. The process according to claim 6, characterized in that the solvent is selected from the group consisting of aliphatic and cycloaliphatic hydrocarbons; aromatic hydrocarbons; cyclic and acyclic ethers, esters and ketones.
8. 8. A process for the preparation of p-carbomethoxycinnamic acid characterized in that it comprises reacting methyl p-formylbenzoate and ketene ep in the presence of a potassium salt to form p-carbomethoxycinnamic acid.
9. 9. The process according to claim 8, characterized in that the potassium salt is selected from the group consisting of potassium acetate, potassium carbonate, potassium benzoate, potassium cinnamate and potassium propionate.
10. 10. The process according to claim 8, characterized in that the molar ratio of potassium salt to methyl p-formylbenzoate is less than 0.50.
11. 11. The process according to claim 8, characterized in that the molar ratio of potassium salt to methyl p-formylbenzoate is less than 0.20.
12. 12. The process according to claim 8, characterized in that the source of ketene is selected from the group consisting of acetone, diketene, acetic anhydride, and acetic acid.
13. 13. The process according to claim 8, characterized in that it also comprises the addition of a solvent.
14. The process according to claim 13, characterized in that the solvent is selected from the group consisting of aliphatic and cycloaliphatic hydrocarbons, aromatic hydrocarbons, cyclic and acyclic ethers, esters and ketones.
15. 15. A process for the preparation of methyl p-vinylbenzoate characterized in that it comprises thermal decarboxylation of p-carbomethoxycinnamic acid, in the presence of copper powder, to form methyl p-vinylbenzoate.
16. 16. A process for the preparation of p-vinylbenzoic acid characterized in that it comprises reacting the methyl p-formylbenzoate and ketene, in the presence of a potassium salt, to form methyl p-vinylbenzoate; followed by hydrolysis of methyl p-vinylbenzoate to p-binylbenzoic acid.
17. 17. The process according to claim 16, characterized in that the hydrolysis of methyl p-vinylbenzoate is catalyzed by a base.
18. 18. The process according to claim 16, characterized in that the hydrolysis of methyl p-vinylbenzoate is catalyzed by a base.
19. 19. A latex polymer composition characterized in that it comprises the reaction product of methyl p-vinylbenzoate and at least one ethylenically unsaturated monomer.
20. The composition according to claim 19, characterized in that the ethylenically unsaturated monomer is selected from the group consisting of non-acidic vinyl monomers, vinyl monomers and / or mixtures thereof.
21. 21. The composition according to claim 20, characterized in that the non-acidic vinyl monomer is selected from the group consisting of acetoacetoxyethyl methacrylate, acetoacetoxyethyl acrylate, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, sodium acrylate, isobutyl, isobutyl methacrylate, ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl acrylate, isoprene, octyl acrylate, octyl methacrylate, iso-octyl acrylate, iso-octyl methacrylate, trimethylopropyl triacrylate, styrene, a-methylstyrene, glycidyl methacrylate, carbodiimide methacrylate, Ci-Cis alkyl crotonates, di-n-butyl maleate, a or β-vinylnane, di-octylmaleate, allyl methacrylate, di-allyl maleate, allyl malonate, methoxybutenyl methacrylate, isobornyl methacrylate, hydroxybutenyl methacrylate, isobornyl methacrylate, hydroxybutenyl methacrylate, hydroxyethyl (meth) acrylate, hydroxy (meth) acrylate propyl, acrylonitrile, vinyl chloride, vinylidene chloride, vinyl acetate, vinyl ethylene carbonate, epoxybutene, 3,4-dihydroxybutene, hydroxyethyl (meth) acrylate, methacrylamide, acrylamide, butylacrylate, ethylacrylamide, butadiene, vinyl ester monomers , vinyl (meth) acrylates, isopropenyl (meth) acrylate, (meth) acrylates of cycloaliphatypepoxy, ethylformamide, 4-vinyl-1,3-dioxolan-2-one, 2,2-dimethyl-4-vinyl-l, 3-dioxolane, and 3,4-di-acetoxy-1- butene or a mixture thereof.
22. 22. The composition according to claim 20, characterized in that the vinyl acid monomer is selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, crotonic acid, monovinyl adipate, and mixtures thereof.
23. 23. A latex polymer composition characterized in that it comprises the reaction product of p-vinylbenzoic acid and at least one ethylenically unsaturated monomer.
24. The composition according to claim 23, characterized in that the ethylenically unsaturated monomer is selected from the group consisting of non-acidic vinyl monomers, vinyl acidic monomers and / or mixtures thereof.
25. 25. The composition according to claim 24, characterized in that the non-acidic vinyl monomer is selected from the group consisting of acetoacetoxyethyl methacrylate, acetoacetoxyethyl acrylate, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl, butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl acrylate, isoprene, octyl acrylate, octyl methacrylate, iso-octyl acrylate, isopropyl methacrylate, octyl, trimethylolpropyl triacrylate, styrene, α-methylstyrene, glycidyl methacrylate, carbodiimide methacrylate, C?-C? 8 alkyl crotonates, di-n-butyl maleate, α or β-vinylnaphthalene, di-octylmaleate, methacrylate allyl, di-allyl maleate, di-allyl malonate, methoxybutenyl methacrylate, isobornyl methacrylate, hydroxybutenyl methacrylate, isobornyl methacrylate, hydroxybutenyl methacrylate, (m et) hydroxyethyl acrylate, hydroxypropyl (meth) acrylate, acrylonitrile, vinyl chloride, vinylidene chloride, vinyl acetate, vinylethylene carbonate, epoxybutene, 3,4-dihydroxybutene, hydroxyethyl (meth) acrylate, methacrylamide, acrylamide, butylacrylamide, ethylacrylamide, butadiene, vinyl ester monomers, vinyl (meth) acrylates, isopropenyl (meth) acrylate, cycloalifaticepoxy (meth) acrylates, ethylformamide, 4-vinyl-1,3-dioxolan-2-one, 2, 2-dimethyl-4-vinyl -1, 3-dioxolane, and 3,4-di-acetoxy-1-butene or a mixture thereof.
26. 26. The composition according to claim 24, characterized in that the vinyl acid monomer is selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, crotonic acid, monovinyl adipate, and mixtures thereof.