Transesterification Of Methyl Methacrylate Research Articles

Synthesis and Characterization of Novel Quaternary Ammonium Urethane-Dimethacrylate Monomers-A Pilot Study.

Six novel urethane-dimethacrylate analogues (QAUDMAs) were synthesized and characterized. They consisted of the 2,4,4,-trimethylhexamethylene diisocyanate (TMDI) core and two methacrylate-terminated wings containing quaternary ammonium groups substituted with alkyl chains of 8, 10, 12, 14, 16, or 18 carbon atoms. QAUDMAs, due to the presence of quaternary ammonium groups, may have possible antibacterial effects. Since they showed satisfactory physicochemical properties, they will be subjected to further research towards the development of dental composites with a capacity to reduce secondary caries. The synthesis of QAUDMAs included three stages: (i) transesterification of methyl methacrylate (MMA) with N-methyldiethanolamine (MDEA), (ii) N-alkylation of the tertiary amino group with alkyl bromide, and (iii) addition of TMDI to the intermediate achieved in the second stage. The formation of QAUDMAs was confirmed by 1H and 13C NMR. They were characterized for density (dm), viscosity (η), refractive index (RI), glass transition temperature (Tg), polymerization shrinkage (S), and degree of conversion (DC). QAUDMAs were yellow, viscous resins (the η values ranged from 1.28 × 103 to 1.39 × 104 Pa·s, at 50 °C). Their RI ranged from 1.50 to 1.52, Tg from −31 to −15 °C, DC from 53 to 78%, and S from 1.24 to 2.99%, which is appropriate for dental applications.

Polymethacrylates: Pour point depressants in diesel oil

A variety of techniques have been employed in order to reduce problems caused by the crystallization of paraffin during the production and/or transportation of paraffin oils and derivatives. Methacrylate copolymers are known as additives which reduce the pour point of these oils. This paper describes the synthesis, characterization and performance evaluation of these copolymers, having as an initial step the synthesis of the alkyl methacrylate monomers by transesterification of methyl methacrylate (MMA) with C 14, C 16 and C 18 fatty alcohols. The copolymerization of these monomers with MMA was then performed, with molar ratios of 30:70, 50:50 and 70:30 for alkyl methacrylate:methyl methacrylate. All products were characterized by FTIR, 1H NMR and gel permeation chromatography (GPC). All the methacrylic copolymers lead to a large reduction in the pour point of samples of Brazilian diesel oil. Oil samples containing 50 ppm of the polymeric additive with ca. 70% octadecyl methacrylate units showed a 22 °C reduction in their pour points, thus establishing the large efficiency of the products synthesized in this work.

Drying and semidrying oil macromonomers. III. Styrenation of sunflower and linseed oils

AbstractStyrenation of drying and semidrying oils, namely sunflower and linseed oils, via the macromer technique was studied. For this purpose, the macromonomers of the oils were prepared by transesterification of methyl methacrylate (MMA) with the corresponding partial glycerides (PG). Subsequent styrenation was achieved by free radical copolymerization of the macromonomers with styrene using benzoyl peroxide as the initiator. The viscosity and the film properties of the products were studied and compared. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2373–2376, 2003

Homogeneous and supported titanates as catalysts for transesterification of acrylic esters

The transesterification of methylmethacrylate with 1-dodecanol has been studied by using Bronsted acid and Lewis acid type catalysts either for homogeneous or heterogeneous systems. Initial rates studies in a batch reactor lead to a greater efficiency for the Lewis acid catalysts (soluble or supported titanates). The activity of the supported catalyst can be linked to the molecular association of the titanates during the fixation on the silica support, the existence of monomeric species corresponding to the most important activity. The nature of the support has also an influence: for the same density of titanium atoms, a smaller surface area leads to a better efficiency.

Biocatalytic synthesis of acrylates in supercritical fluids: tuning enzyme activity by changing pressure.

Supercritical fluids are a unique class of nonaqueous media in which biocatalytic reactions can occur. The physical properties of supercritical fluids, which include gas-like diffusivities and liquid-like densities, can be predictably controlled with changing pressure. This paper describes how adjustment of pressure, with the subsequent predictable changes of the dielectric constant and Hildebrand solubility parameter for fluoroform, ethane, sulfur hexafluoride, and propane, can be used to manipulate the activity of lipase in the transesterification of methylmethacrylate with 2-ethyl-1-hexanol. Of particular interest is that the dielectric constant of supercritical fluoroform can be tuned from approximately 1 to 8, merely by increasing pressure from 850 to 4000 psi (from 5.9 to 28 MPa). The possibility now exists to predictably alter both the selectivity and the activity of a biocatalyst merely by changing pressure.

Solventless transesterification of methyl methacrylate with ethylene glycol. A kinetic approach

The kinetics of solventless transesterification of methyl methacrylate with ethylene glycol has been studied to establish the optimal conditions for ethylene glycol monomethacrylate synthesis. The kinetic data presented show strong dependence of kinetic parameters on initial reagents ratio.

AlPO4 as catalyst in organic reactions. IV. Transesterification of methyl methacrylate

The transesterification of methyl methacrylate with n-BuOH has been studied in solid-liquid and gas solid conditions. The reaction takes place with better selectivity in solid-liquid than in solid-gas conditions. The influence of temperature, ester/alcohol ratio, etc., on the transesterification process are discussed.

Characteristic Ratios of Polymethacrylates

Abstract Dilute solution properties of polymethacrylates have been studied extensively over the past 30 or so years. Probably more different polymethacrylates have been prepared and characterized than any other class of polymer. A major reason for this intense interest is the ease with which various methacrylate monomers can be prepared, e.g., by esterification of methacrylic acid with the appropriate alcohol or trans-esterification of methyl methacrylate. Also, most methacrylate monomers are easily polymerized to high molecular weights by free radical methods in bulk, in dilute solution, or in emulsion. These polymerizations are generally free of chain transfer reactions which lead to branching or cross linking, so long as conversion to polymer is kept at fairly low levels. Many methacrylates also polymerize via anionic mechanisms. Thus, linear polymethacrylates with a wide variety of side groups can be readily prepared.

Transesterification of Methyl Methacrylate with Amino Alcohols. Preparation of a Primary Aminoalkyl Methacrylate and 2-Isopropenyl-4,4-dimethyloxazoline1

Transesterification of Methyl Methacrylate with Amino Alcohols. Preparation of a Primary Aminoalkyl Methacrylate and 2-Isopropenyl-4,4-dimethyloxazoline¹