Methacrylic Acid Esters Research Articles

Electrochemistry of ruthenium metallocenes: Part 3. Synthesis and properties of ruthenium [22]paracyclophane complexes with methacrylic acid and methacrylate ester substitutents

Four [22](1,4)cyclophanes bearing one or two methacrylate ethyl ester and methacrylic acid substituents and ruthenium arene complexes of these compounds are synthesized. The structure of the ligands and the complexes is characterized by NMR spectroscopic techniques. For some of the ligands X-ray crystal structure analyses support the assignments. The mono-substituted [22](1,4)cyclophanes prefer to form anti-complexes, with the Ru central atom bound to the unsubstituted aromatic deck. The irreversible electrochemical oxidation of the cyclophanes is studied by cyclic voltammetry, and, in contrast to mono- and divinyl[22](1,4)cyclophanes does not produce permanent films on the electrode. The electrochemical reduction of the complexes proceeds as a two-electron process and produces the kinetically stable corresponding Ru0 species. The anodic oxidation of the title compounds is irreversible and leads to filming of the electrode surface.

The polymerisation kinetics of lower dialkyl itaconates

The free radical polymerisation kinetics of diethyl- (DEI), dipropyl- (DnPI), dibutyl- (DnBI), and dihexyl itaconate (DHI) in the bulk were studied in the temperature range from 50 to 70°C. The concentration of the initiator, 2,2′-azoisobutyronitrile (AIBN), was varied between 0.02 and 0.085 mol/dm3. The rate of polymerisation (Rp), degree of polymerisation (DP), overall polymerization rate constant (K), the ratio of the propagation and termination rate constants (kp/kt1/2), as well as the chain transfer constant to monomer (CM) were determined. The values of Rp, K, and kp/kt1/2 of the investigated monomers all increase with increasing size of the alkyl group in the ester substituent, whereas CM decreases when going from the dimethyl to the dihexyl ester. The values of CM are larger than the corresponding values for the alkyl esters of methacrylic acid.

The polymerisation kinetics of lower dialkyl itaconates

The free radical polymerisation kinetics of diethyl- (DEI), dipropyl- (DnPI), dibutyl- (DnBI), and dihexyl itaconate (DHI) in the bulk were studied in the temperature range from 50 to 70°C. The concentration of the initiator, 2,2′-azoisobutyronitrile (AIBN), was varied between 0.02 and 0.085 mol/dm3. The rate of polymerisation (Rp), degree of polymerisation (DP), overall polymerization rate constant (K), the ratio of the propagation and termination rate constants (kp/kt1/2), as well as the chain transfer constant to monomer (CM) were determined. The values of Rp, K, and kp/kt1/2 of the investigated monomers all increase with increasing size of the alkyl group in the ester substituent, whereas CM decreases when going from the dimethyl to the dihexyl ester. The values of CM are larger than the corresponding values for the alkyl esters of methacrylic acid.

Study of polymerization kinetics of acrylic and methacrylic acid esters at low conversions

The kinetics of high-energy radiation initiated polymerization of acrylate and methacrylate monomers were studied in dilute cyclohexane solutions. The absorption spectra of the intermediates were obtained by pulse radiolysis with optical detection. In solutions of acrylates at longer times after the pulse the presence of oligomer radicals was observed. In solutions of methacrylates the beginning of the oligomerization reaction was detected at higher monomer concentrations. From the kinetic curves the rate coefficients of termination were calculated.

Brominated copolymers of reduced flammability

Abstract The copolymerization reaction of important brominated monomers with a number of known commercial vinyl monomers as well as some characteristic properties of the prepared copolymers, particularly their thermal stability and flammability are reviewed. The considered bromine-containing monomers primarily were: vinyl bromide, brominated styrenes, aliphatic and aromatic esters of acrylic acid and methacrylic acid, brominated phenylmaleimides and phosphorous–bromine vinyl monomers. The results show that copolymers of bromine-containing monomers posesses flame retardant properties that compared favourably with other brominated but low molecular weight compounds.

Formation of six-membered cyclic anhydrides by thermally induced intramolecular ester condensation in Eudragit E film

Eudragit E, a copolymer of N, N-dimethylaminoethyl methacrylate and neutral methacrylic acid esters, has been found to form six-membered cyclic anhydrides via intramolecular ester condensation by a heating process only, without adding any catalyst or initiator. A novel reflectance Fourier transform infrared microspectroscopy system equipped with differential scanning calorimetry (FTIR/DSC) was used to determine the thermal-dependent anhydride formation of Eudragit E film. The anhydride-related IR peaks at 1801, 1763 and 1007 cm −1 appeared from 180°C and increased with the heating temperature, while the peaks at 2820 and 2770 cm −1 for the dimethylamino group reduced gradually with the increase of temperature, strongly suggesting that the anhydride formation by ester condensation started above 180°C. The appearance of peaks at 1801 and 1763 cm −1 not only illustrates the asymmetric and symmetric stretching vibration mode of the carbonyl group existing in the anhydride structure, but also exhibits the formation of six-membered cyclic anhydrides during the heating process. Moreover, the higher peak intensity ratio of 1763 cm −1/1801 cm −1 also reveals the predominant role of intramolecular ester condensation in anhydride formation in Eudragit E film.

Polymorphism of acrylic and methacrylic acid esters containing long fluorocarbon chains and their polymerizability

The molecular aggregation of acrylic and methacrylic acid esters containing long-fluorocarbon chains: 2-(perfluoroalkyl)ethyl acrylate (FFnEA) and 2-(perfluoroalkyl)ethyl methacrylate (FFnEMA) (F(CF2)nCH2CH2OCOC(X)=CH2, where X=H, CH3 and n=6, 8, 10) was investigated by differential scanning calorimetry (DSC) and temperature controlled X-ray powder diffraction measurement. These compounds exhibited some characteristic polymorphic behaviors depending on the length of fluorocarbon chain and the α-position methyl group. The solid-state polymerization by γ-ray irradiation was studied for these compounds in the various crystal forms. In the solid-state polymerization, highest polymerizability was observed in the crystal form that exists in the highest temperature region for each compound.

Bimodal Release of Theophylline from “Seed–Matrix” Beads Made of Acrylic Polymers

The purpose of this research was to design a “seed–matrix” structure for an in vitro bimodal theophylline release profile and to investigate the mechanism and kinetics of drug release as well as the influence of various factors on the properties of the theophylline-containing microspheres. “Seed” microspheres with high theophylline content were prepared from Eudragit® L100 and Eudragit S100, copolymers of methyl methacrylate and methacrylic acid, by the solvent removal process. The seed–matrix beads were subsequently prepared by incorporation of the seed microspheres into Eudragit RL100, a copolymer of acrylic and methacrylic acid esters with a low content of quaternary ammonium group. Increasing the size of encapsulated drug particles and the rate of agitation during the preparation, or decreasing the amount of surfactants led to an increase in the size of the microspheres produced. Scanning electron microscopy revealed porous morphology of the microspheres. The release rate of theophylline was enhanced as the content of methacrylic acid in the copolymer increased and the size of the microspheres decreased. The kinetics of drug release from the microspheres was controlled by swelling at the early stage and by diffusion in the later stage. The drug was released from the matrix of the seed–matrix beads at pH 1.2 and from both the matrix and the seeds at pH 6.8. A bimodal release profile of theophylline was obtained from the seed–matrix beads made of acrylic polymers.

New acrylic titanium polymers: 1. Synthesis and characterisation of new titanium trialkoxide methacrylate monomers prepared via the esterification of methacrylic acid by titanium tetraalkoxides

In order to obtain a new family of acrylic organotitanium polymers which could be of major interest in the field of non-toxic, self-polishing, antifouling coatings, five acrylic organotitanium monomers, three of which are new, were synthesised. They were analysed by n.m.r. and FTi.r. spectroscopy as well as by microanalysis. Their main features were studied from a structural point of view. The presence of one to three types of structure was shown. The results were linked to the influence of the steric hindrance of the alkoxy groups attached to the titanium atom.

Polymerization of methacrylic acid esters with the aged system of lanthanum versatate and p‐chlorobenzenediazonium tetrafluoroborate

AbstractThe aged system of lanthanum versatate (1) and p‐chlorobenzenediazonium tetrafluoroborate (2) was found to initiate effectively the radical polymerization of acrylic monomers including alkyl methacrylates, butyl acrylate and acrylonitrile, although its initiating activity is lower than that of the non‐aged system. The polymerization of methyl methacrylate (3) with the aged 1/2 system was studied kinetically in acetone. The initial polymerization rate (Rp) is expressed by Rp = Kċ[aged 1/2]0.80 ċ [3]1.1 at 50°C. The overall activation energy of the polymerization is 59.0 kJ ċ mol−1. The molecular weight of the resulting poly(3) formed in the early stage increases with increasing conversion. The polymerization system involves a persistent radical showing a four‐line EPR spectrum with a g‐value of 2.004. A three‐line spectrum due to the nitroxyl radical was also observed at lower monomer concentrations. The total concentration of persistent radicals was found to correspond well to the instantaneous polymerization rate. The copolymerization of styrene (M1) and 3 (M2) with the aged initiator system was examined at 50°C in acetone. r1 and r2 are 0.19 and 0.47, respectively. The former is considerably smaller than that (0.52) reported for the conventional radical polymerization.

First efficient palladium-catalyzed Heck reactions of aryl bromides with alkyl methacrylate

An efficient palladium-catalyzed coupling reaction of aryl bromides with butyl methacrylate has been developed. Depending on the reaction conditions various amounts of butyl 3-aryl-2-methylpropenoate and butyl 3-aryl-2-methyliden-propenoate as well as double arylated products were produced. Superior turn over numbers up to 8300 and turn over frequencies up to 1000 h −1 for Heck reactions of aryl bromides with methacrylic acid ester have been obtained for the first time.

Fettpolymere – Herstellverfahren und Eigenschaften

AbstractThe radical polymerization of esters of acrylic, methacrylic or crotonic acid with fatty alcohols proved to be an efficient method for production of polymers with hydrophobic moieties. By co‐polymerisation with hydrophilic co‐monomers ‐ such as maleic anhydride ‐ copolymers with a broad spectrum of properties can be designed. As an example the copolymerisation of fatty crotonates with maleic anhydride was studied in detail. The reaction was carried out as bulk polymerisation in a semi‐batch process. By this method the compatibility problems of the two monomers, which have very different hydrophilicities could be overcome. The product acts as a very effective fat liquoring agent in leather treatment: the maleic moieties cause an outstanding fixing of the agent on the leather and the fatty crotonate moieties create a very smooth leather. Terpolymers of fatty acrylates, hydrophilic monomers and terpenes could also be synthesized in a similar way. These terpolymers proved to be useful as dispersing agents for pigments in paints and varnishes.

An efficient method for lipase-catalysed preparation of acrylic and methacrylic acid esters

Novozym 435 — a commercially available immobilized lipase from Candida antarctica — shows an activity for the transesterification using acrylic or methacrylic methylester as solvent and as acylating agent superior to all other enzymes tested. This transesterification is very fast compared to other enzyme-catalysed reactions (1.5 h). Novel acrylic and methacrylic esters from unsaturated fatty alcohols can be prepared this way in yields of 65 to 94 % and under mild conditions (30 °C, atmospheric pressure).

Lichen planus-like contact dermatitis due to methacrylic acid esters

We report a patient who had lichen planus-like lesions on sites repeatedly exposed to methacrylic acid esters used in the car industry. Histologically, the lesions showed all the features of classical lichen planus. Patch testing revealed positive reactions to methacrylic acid esters in concentrations as low as 5 x 10(-3)%. As dental devices contain methacrylic acid esters, it is possible to speculate that methacrylic acid esters may be one of the causative agents for oral lichen planus.

Lichen planus-like contact dermatitis due to methacrylic acid esters

Lichen planus-like contact dermatitis due to methacrylic acid esters

Diastereoselectivity and enantioselectivity in the addition of chiral imines of 2-methylcyclohexanone to crotonic and methacrylic acid esters

Additions of the chiral imine (reacting as its secondary enamine tautomer) obtained from (S)-1-phenylethylamine and 2-methylcyclohexanone were performed with the phenyl ester of crotonic and methacrylic acid as well as with their methyl ester. In each example, the stereochemical relationship of the substituents in the major adduct was shown to be the one predicted in a previous theoretical calculation which established that the reactants complex has a chairlike geometry. In all the examples, the diastereoselectivity is superior to 98%. The enantioselectivity of the reactions is excellent as is usually the case with unsubstituted electrophilic olefins, the example with phenyl methacrylate being particularly remarkable (de and ee >99%). In each case the favored diastereofacial selectivity is again in accordance with the rule elaborated previously. Relevant facts about the influence of the substituents upon the reactivity, the proportion of regioisomers, the stereoselectivity, and the enantioselectivity of the reaction are given.

Assessment of structurally related chemicals: Toxicity and ecotoxicity of acrylic acid and acrylic acid alkyl esters (acrylates), methacrylic acid and methacrylic acid alkyl esters (methacrylates)

BUA compiled the available data on toxicity and ecotoxicity for several acrylic and methacrylic acid esters and their corresponding acids. A comparison of these data revealed a qualitative similarity in the toxicological and ecotoxicological properties of the compounds considered. The data indicate that methacrylates are less reactive than the corresponding acrylates.

Proton Nuclear Magnetic Resonance Spectroscopic Detection and Determination of Ethylene Glycol Dimethacrylate as a Contaminant of Methyl Methacrylate Raw Material

A simple, specific, and accurate proton nuclear magnetic resonance (1H NMR) spectroscopic method is presented for detection and assay of ethylene glycol dimethacrylate dimer as a contaminant of methyl methacrylate monomer. In addition to minimizing exposure of the analyst to the irritant and toxic methacrylic acid esters, the proposed method requires no sample preparation. Quantitations are based on integrals for signals of methylene protons of ethylene glycol dimethacrylate at 4.37 ppm and methyl protons of methyl methacrylate at 3.70 ppm. Analysis of 10 synthetic mixtures of the monomer with 1-11% of dimer yielded a dimer recovery of 100.5 +/- 2.05% (mean +/- standard deviation). Correspondence (correlation coefficient, r = 0.9999) between the amount of dimer added and the amount found was excellent. The proposed method measures as little as 1% of dimer.

Colorless methacrylic acid and acrylic acid esters

Colorless methacrylic acid and acrylic acid esters

Drug Release and Surface Morphology Studies on Salbutamol Controlled Release Pellets

AbstractThe air suspension technique was employed to prepare controlled release pellets of Salbutamol (as the sulphate). The aim of the present study was to determine the influence of various film coating additives on the release characteristics and surface morphology features of salbutamol sulphate pellets coated with EudragitR RS30D which is the aqueous dispersion of a polymer synthesised from acrylic and methacrylic acid esters. Surface morphology features, which were examined using Scanning Electron Microscopy, revealed that triethyl citrate (plasticiser) was essential for the coalescence of polymeric membranes around the drug-loaded spheres. Higher concentrations (12.5%) of triethyl citrate displayed a more uniform and continuous polymer film resulting in a slower in vitro drug release. Micrographs of the cross-sections of pellets with higher concentrations of EudragitR RS30D indicated the formation of thicker polymer membranes which accounted for the slower drug release rates. Hydroxypropyl methylce...