Batch methacrylic acid

Shellac is the oldest known material that has been used as enteric coating material. However, as a natural material, it lacks a crucial quality criterion of more modern polymers (i.e., batch-to-batch reproducibility). Hence, the most commonly used polymers today are the synthetic methacrylate copolymers or semisynthetic derivatives of cellulose. The main structural element of these polymers is an acidic function (either phthalate or methacrylic acid), which is responsible for the pH-dependent dissolution. 

Ethyleneimine has been also copolymerized in the absence of an initiator by zwitterion copolymerization with maleic anhydride [79] and methacrylic acid [80]. Both copolymers were checked following the batch method for copper(II), uranium(VI) and iron(III) and did not adsorb iron(HI), but copper(II) and uranium(VI) at pH 2. Poly (ethyleneimine-co-methacrylic acid) adsorbed more than 95% UO +. The ions were almost quantitatively eluted by contact of the loaded resin with 1 M aq. H2S04 [79, 80]. 

To synthesize water-soluble or swellable copolymers, inverse heterophase polymerization processes are of special interest. The inverse macroemulsion polymerization is only reported for the copolymerization of two hydrophilic monomers. Hernandez-Barajas and Hunkeler [62] investigated the copolymerization of AAm with quaternary ammonium cationic monomers in the presence of block copoly-meric surfactants by batch and semi-batch inverse emulsion copolymerization. Glukhikh et al. [63] reported the copolymerization of AAm and methacrylic acid using an inverse emulsion system. Amphiphilic copolymers from inverse systems are also successfully obtained in microemulsion polymerization. For example, Vaskova et al. [64-66] copolymerized the hydrophilic AAm with more hydrophobic methyl methacrylate (MMA) or styrene in a water-in-oil microemulsion initiated by radical initiators with different solubilities in water. However, not only copolymer, but also homopolymer was formed. The total conversion of MMA was rather limited (<10%) and the composition of the copolymer was almost independent of the comonomer ratio. This was probably due to a constant molar ratio of the monomers in the water phase or at the interface as the possible locus of polymerization. Also, in the case of styrene copolymerizing with AAm, the molar fraction of AAm in homopolymer compared to copolymer is about 45-55 wt% [67], which is still too high for a meaningful technical application. 

To prepare water-soluble polymers employing CCT, it is necessary to modify the polymerization conditions.312 439 Use of a standard batch reaction leads to hydrolysis of catalyst, changing the catalyst level over the course of the polymerization, yielding a mixture of products and poor control of the reaction. A feed or starved-feed process that adds catalyst over the course of the reaction maintains a constant catalyst level and high conversion. The approach can be applied to a range of monomers such as methacrylic acid, 2-aminoethyl methacrylate hydrochloride, 2-hy-droxyethyl methacrylate, 2-methacryloxyethyl phos-phoryl choline, glycerol monomethyl methacrylate, and 3- O-methacryloyl-1,2 5,6-di- O-isopropylidene-D-glucofuranose. 

Esters of methacrylic acid are obtained directly from acetone cyanohydrin by reaction of the latter with concentrated sulfuric acid to give methacrylamide sulfate, followed by reaction with an alcohol. The process is continuous and the methacrylamide sulfate is not isolated. Acetone cyanohydrin is derived from acetone and hydrogen cyanide (Pig. 15-39), Polymerization Procedures. Of particular importmice to the acrylics is the cast or bulk method of polymerization. This method is employed to produce cast polymethyl methacrylate sheets which are widely used in industrial applications. Careful control of polymerization is required to obtain a bubble-free product with good optical clarity. A typical flow sheet for the production of cast eet is shown in fig. lfi-40. Solution, suspension, and particularly emulsion polymerizations are also, widely used with the acrylics. Such polymerization reactions involve relatively conventional batch-type processes. i... 

Batch Di (3-pentyl) Malate Process Acetaldehyde from Acetic Acid Ethylene by Oxidative Dehydrogenation of Ethane Butadiene to n-Butyraldehyde and n-Butanol Methacrylic Acid to Methylmethacrylate Coproduction of Ethylene and Acetic Acid from Ethane Methylmethacrylate from Propyne Mixed-C4 Byproduct Upgrade Hydrogen Peroxide Manufacture Di-tem fljy-butyl-peroxide Manufacture Vinyl Acetate Process PM Acetate Manufacture Propoxylated Ethylenediamine Petroleum Products Fuel Additives for Cleaner Emissions Gas Manufacture... 

The use of acrylic acid not only led to a functionalization of nanoparticles, but also was important as a structure-directing monomer for the formation of nanocapsules. In this case, the hydrophilic groups of the acrylic acid [30] or methacrylic acid [31] resulted in the formation of a nanocapsule structure, instead of Janus-like or even separate nanoparticles. The copolymerization of the functional n-methylol acrylamide with vinyl acetate was found to follow (in batch miniemulsion) the Mayo-Lewis equation, despite huge differences in the solubility of the monomers in the aqueous continuous phase [32]. A functionality of fluori-nated particles could be easily introduced by copolymerizing fluoroalkylacrylates with protonated monomers, such as acrylic acid and methacryloxyethyltrimethyl ammonium chloride [33]. 

The dispersed phase was injected through a 35 pm hole drilled in the acetate sheet. The formulation for the MIP synthesis, containing the template [(J, S)-propranolol], the monomer (methacrylic acid, MAA), the crosslinker (trimethylolpropane trimethacrylate, TRIM), the photoinitiator (2,2-dimethoxy-2-phenylacetophenone, DMPAP) and a porogenic solvent (acetonitrile), was emulsified at the T-junction with a mineral oil (heavy white) and then photopolymerized by UV irradiation in the spiral-like channel. The resulting MIP particles were compared with those obtained with a conventional batch process. The continuous microsystem-assisted process led to near-monodisperse particles (CV <2%), whereas the conventional process gave particles having a broad range of sizes (CV >10%). The same conclusion holds for... 

A monomer preemulsion, used for miniemulsion polymerisation, was prepared by stirring a mixture of epoxy resin, acrylic monomers, surfactants, costabiliser and water. Miniemulsion polymerisation produced the composite latex. Methacrylic acid and/or dimethylaminoethyl methacrylate were added to introduce the functional groups into the composite latices. The functional groups were introduced either by batch polymerisation or two-stage polymerisation, the latex produced by the two-stage polymerisation method had good polymerisation stability, storage stability and solvent resistance. 11 refs. 

Heterogeneous latices were prepared by a two-stage seeded emulsion polymerisation process at 80C using potassium persulphate as initiator and sodium dodecyl sulphate as emulsifier. Styrene-methacrylic acid (MAA) copolymer latices containing varying amounts of MAA were used as seeds. The second stage polymerisation was performed either as a seeded batch process or as a seeded... 

A study was made of the impact of incorporation of a small amount of carboxylic monomers (acrylic acid or methacrylic acid) into the latex particles in the limited flocculation process, often encountered in the semi-batch surfactant-free emulsion polymerisation of pure butyl acrylate. The possibility of producing carboxylated polybutyl acrylate latices with a smaller particle size was evaluated. The resultant latex was characterised to gain a better understanding of the effect of the surfactant-free technique on their physical properties, e.g. zeta potential, distribution of acrylic acid or methacrylic acid in the particles, and stability towards the added salt, compared with the conventional emulsion polymerisation system stabiUsed by surfactants. 35 refs. 

Fig. 2.3.18 Conversion-time plots for batch polymerization of methacrylic acid with V-50 initiator in different levels of water at 90°C. The starting compositions are given in the plots (Replotted with permission from Wang et al., 1999)...

The esterification process of methacrylic acid with n-propanol and isopropanol have been studied in an experimental, isothermal batch reactor. Basing on experimental results, the rigorous kinetic models were derived including the reversible reactions. The equilibrium constants and kinetic parameters have been determined. 

The saturation of the epoxy groups takes place in a stirred batch reactor by the addition of methacrylic acid to the epoxy resin. Epoxy resin is fed into the reactor and the temperature is raised up to 115 °C. The catalyst and the inhibitor are added to the reaction mixture. 

Batch Polymerization of Methacrylic Acid Initiated by Ammonium... 

Procedure 2-14 is an example of the polymerization of methacrylic acid initiated by ammonium persulfate in a single batch operation, while Procedure 2-15 makes use of the gradual monomer addition technique. This latter approach potentially permits the preparation of poly(meth-acrylic acid) solutions of concentration levels greater than the usual 20-25% level. 

Saha B. and M. M. Sharma, Esterification of formic acid, acrylic acid and methacrylic acid with cyclohexene in batch and distillation column reactors Ion-exchange resins as catalysts. React. Fund Polym. 28, 263-278 (1996). 

As a medium strength liquid (Table 16.1), THF is commonly used also in the coupled methods of polymer HPLC. It promotes desorption of medium polar polymers such as poly(acrylate)s and poly(methacrylate)s including poly(methyl methacrylate) from the nonmodified silica gel. Other strong(er) solvents widely used in the coupled polymer HPLC methods are acetonitrile that exhibits high UV transparency, and dimethyl formamide. The latter solvent readily decomposes into amine and formic acid and its strength may differ from batch to batch. 

Reactor 9 is used to methacrylate the acetoxysilane mixture. First, back-flow condenser 12 is switched on the agitator is switched on and the jacket of the apparatus is filled with vapour then the contents of reactor 9 are heated to 60°C. At this temperature glycolmethacrylate self-flows from batch box 10 at such speed that the temperature in the reactor does not exceed 65°C. After the glycolmethacrylate has been loaded, the contents of reactor 9 are agitated at 60-65°C for one more hour then condenser 12 is switched into the direct operation mode, vacuum is created (the residual pressure is 130-80 GPa), and acetic acid is distilled into receptacle 13 at 40-50 °C (in vapour) reactor 9 is periodically sampled to determine the acid number (a.n.). If the analysis is satisfactory (a.n. = 450-500 mg/g), reactor 9 is loaded with toluene from batch box 11. 

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