Acrylic Compounds Research Articles

Screening for contact allergy to artificial nails

27 patients (26 women and 1 man), all in contact with artificial nails, were tested for acrylic compounds, known to be present in nail cosmetics. The patch test results obtained in these patients demonstrated that 2-hydroxyethyl methacrylate and ethyl cyanoacrylate were the only 2 allergens needed to diagnose contact allergy to acrylic-containing nail cosmetics, except for 1 patient who reacted only to her nail preparation used and in which we were unable to identify the allergen. This concerns clearly a limited number of patients. The purpose was, however, to detect the most valuable allergen(s) to be used in a dermatologist's practice, in which not all possible allergens can be tested, in order to diagnose such cases.

Toward Diels−Alder Reactions on a Solid Support Using Polymer Bound N‐Substituted 3‐Hydroxy‐4,4‐dimethyl‐2‐pyrrolidinone Acrylate Derivatives

AbstractSeveral N‐substituted 3‐hydroxy‐4,4‐dimethyl‐2‐pyrrolidinone acrylate derivatives, selected to allow their attachment to a polymer, have been prepared and tested as dienophiles in the Diels−Alder reaction. The experiments, performed under TiCl4 catalysis in solution or the solid phase with isoprene and cyclopentadiene as dienes, pointed out the difficulties associated with some of these compounds that failed to give the corresponding cycloadduct. 13C NMR studies provided some evidence regarding the nature of the interactions between the acrylate compounds and TiCl4. It appears that the outcome of the reaction is dependent on the acrylate structure and that the 4‐(3‐hydroxy‐4,4‐dimethyl‐2‐oxopyrrolidin‐1‐yl)benzoic acid acrylate derivatives are highly efficient to give the cycloadduct in good yield and with high regio‐ or endoselectivity in both solution and solid‐phase reaction conditions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Effect of pressure on sterically hindered reactions with late transition states

AbstractThe effect of high pressure is examined in two types of sterically congested reactions presenting late transition states: isopolar Diels–Alder cycloadditions of isoprene and quinones of various steric environment and conjugate additions of tert‐butylamine and acrylic compounds. In the Diels–Alder cycloadditions, pressure has no enhanced kinetic sensitivity in sterically demanding reactions compared with unhindered ones. This is due to the structural closeness of the transition state and product. At variance, in the conjugate addition of amines, the effect of pressure is magnified with increasing steric congestion at the reaction centres. This is ascribed to enhanced electrostriction with removal of steric hindrance to ionization. Copyright © 2004 John Wiley & Sons, Ltd.

High pressure relief of steric inhibition in ionogenic organic reactions

The pressure effect is examined in an ionogenic reaction, the phosphine-catalyzed cyanoalkylation of acrylic nitriles by primary alcohols. The increase of rate constants with pressure is enhanced with increasing chain length of the alcohol and depends on steric constraints imposed by the substituting methyl group in the acrylic compound. The pressure effect is in line with a considerable electrostriction depending on steric hindrance to ionization. Pressure is confirmed as a favorable determining factor in sterically hindered reactions.

Conjugate Addition of Alcohols to Acrylic Compounds Catalyzed by a Bifunctional Ruthenium−Acetamido Complex

The ruthenium−acetamido complex [(PCy3)2(CO)(CH3CONH)(i-PrOH)RuH] (1) was found to be an effective catalyst for the conjugate addition of alcohols to acrylic compounds under mild reaction conditions to form β-alkoxynitrile compounds. The bifunctional activity of 1 from the Lewis acid ruthenium center for facilitating N-coordination of acrylonitrile and the basic amido ligand for mediating heterolytic alcohol O−H bond cleavage have been proposed for the catalytic reaction.

Effect of Small Additions of Stabilizer and Pigments on the Degree of Bulk Curing of a Filled Photopolymer

The effect exerted by additions of stabilizer and pigments to oligoether acrylate compounds filled with finely dispersed silica on the degree of curing and its variation with depth was examined.

On the structure and physicochemical properties of acrylic compounds

The chemical structure of four acrylic polymers (P1-P4) used for producing dental cements was studied by FTIR, 1 H and 13 C NMR, using polyaclylic acid (PAA) as a reference compound. Both, P1 and P2 are PAA polymers containing low concentration (<5 wt.%) of a carboxylic precursor. Besides, sample P2 contains also traces of the monomer (acrylic acid). Sample P3 is a random co-polymer (acrylic acid/methyl acrylate) in ratio 2: 1, whereas sample P4 is an oligomer of 2-hydroxyethylacrylate. Three thermodynamic models were applied to the study of the perturbed and non-perturbed molecular parameters of the polymers using viscosimetric and chromatographic determination of their molecular weights. The best fitting of the experimental results was obtained by the Flory-Fox-Schaefgen model In perturbed conditions samples P1 and P2 show the presence of flexible chains, while samples P3 and P4 contain semi-rigid chains. The lyophilization of the polymers at 50°C resulted in the formation of hydrolysable cyclic anhydrides (soluble fraction) and in chemical cross-linking (insoluble fraction).

Synthesis and photosensitivity of acryloylmorpholine copolymers with a pendant (meth)acryloyl group

AbstractWe have developed new photopolymers that have superior waterproof properties and that can easily interact with polyfunctional acrylate compounds, thus serving as hydrophobic photocrosslinking reagents. Acryloylmorpholine monomers whose homopolymers were less moisture absorbing than the usual water‐soluble polymers but were still water soluble to a good degree, were copolymerized with other acryloyl monomers. We then introduced the photosensitive (meth)acryloyl group to side chains of the resulting polymers. Among six copolymers examined, the copolymers composed of acryloyl morpholine, hydroxyethyl acrylate, ethyl, or methyl methacrylate, and methacryloyl isocyanate were found to have nicely balanced hydrophilicity and waterproof properties, in addition to good compatibility with hydrophobic photocrosslinking reagents. The composite polymers thus obtained were confirmed to be promising photopolymers usable even in a highly humid environment. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 684–692, 2003

Spray dried Eudragit microparticles as encapsulation devices for vitamin C.

The aim of the present paper was to study production of methacrylate microparticles for the delivery (administration) of ascorbic acid via the oral route. Vitamin C is an important antioxidant that may be involved in the reduction of the risk of certain types of cancer, such as colorectal cancer. As polymers different acrylic compounds were considered, namely Eudragit RL, L and RS. Spray-drying was used as preparation method of vitamin C/Eudragit microspheres. Microspheres were first characterized by size and morphology by scanning electron microscopy, then in vitro release kinetics by mean of dialysis method were studied. Although the produced microparticles were unable to slow down the release of the drug with respect to the free form of ascorbic acid, these microspheres showed a good morphology and size distribution that permit to propose them as candidate for the delivery of vitamin C as associated therapy in the treatment of colorectal cancer by oral route.

Comb-Like Polymer Thin Films Prepared by Ionization-Assisted Deposition of Acrylate Compounds

ABSTRACTAlkylacrylate compounds were deposited by the ionization-assisted deposition (IAD) method to form thin films of comb-like polymers having long alkyl side chains on the vinyl polymer backbone. From the source material of n-octadecyl acrylate, polymer thin films having average molecular weight of 6000 were obtained at the polymer yield of 45 to 65%. For the preparation of fluorinated polymer thin films, 1H, 1H, 11H-eicosafluoroundecyl acrylate was used as the source material. Although the conventional evaporation method could not accumulate any films with this material, the IAD was able to produce insoluble thin films that have large contact angle against water droplet. In either material, the polymerization reaction was enhanced with increasing electron emission current for IAD. These results indicate that the IAD enables the preparation of thin polymer coatings that have polyethylene or Teflon-like properties without using the solvents.

The influence of laccase on the chemo-enzymatic synthesis of lignin graft-copolymers

The mechanism unterlying the chemo-enzymatic graft copolymerization of lignin with acrylic compounds was studied. When lignin sulfonate (LS) was incubated with the phenoloxidase laccase in the presence of a peroxide species ( t-butylhydroperoxide, i.e. t-BHP), the decrease of the phenolic groups was significantly higher than when LS was incubated with laccase or t-BHP, separately. The enzymatic oxidation of the phenolic groups did lead to the formation of quinones; however, the number of quinone groups formed in LS in the presence of t-BHP was not significantly higher than in its absence. Still, a certain proportion of the quinones formed in the presence of t-BHP appeared to be further oxidized resulting in an opening of the aromatic rings. In addition, the rate of LS polymerization, i.e. its increase in M w instigated by laccase, was significantly reduced in the presence of t-BHP even though the activity of laccase was only slightly affected by the peroxide. Incubation of LS with laccase prior to the grafting reaction resulted in a significant increase of the spin concentration as detected in the EPR spectra. In spite of a high steady state concentration of radicals, the generation rate of these radicals in pre-incubated LS was lower than in unpretreated LS. Thus, the polymer yields obtained with pre-incubated LS were lower than those obtained with unpretreated LS.

ChemInform Abstract: Synthesis of Hindered Functionalized Ethers via High‐Pressure Addition of Alcohols to Acrylic Compounds.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis of hindered functionalized ethers via high-pressure addition of alcohols to acrylic compounds

The phosphine-catalyzed 1,4-addition of alcohols to activated alkenes is studied from a synthetic point of view. α- or β-Substituted acrylic compounds react sluggishly or not at all. In this case, high-pressure activation can remove steric inhibition leading to good yields of the corresponding ethers. Reactions involving crotonic compounds (hindered β reaction center) show higher pressure dependence than the corresponding additions of alcohols to methacrylic analogs (free β reaction center). This is in agreement with the concept that sterically demanding reactions show enhanced sensitivity to pressure. The result, obviously, is of high synthetic value as pressure may be capable of removing steric inhibition.

ChemInform Abstract: Modified Guanidines as Chiral Superbases: Application to Asymmetric Michael Reaction of Glycine Imine with Acrylate or Its Related Compounds.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Cross-reactions of multifunctional methacrylates and acrylates

Dental acrylic monomers (that is, acrylates and methacrylates) are important occupational sensitizers. Acrylic monomers may also cause allergic reactions in dental care. Unfortunately, acrylic monomers cross-react—that is, allergic sensitization induced by one acrylic compound extends to one or more other acrylic compounds. Therefore, sensitized individuals are often multiallergic and, accordingly, cannot be exposed to any of the compounds. In the present review aspects of cross-reactivity in general and data from animal studies of cross-reactivity of multifunctional methacrylates and acrylates are summarized. A multitude of acrylic monomers is used in dentistry, and when patients or dental personnel become sensitized, it is of great importance to identify the dental acrylic preparations to which the sensitized individual can be exposed. Sensitized dental workers are known to have ceased working in dentistry owing to occupational allergic contact dermatitis or asthma, caused by dental acrylic monomers. Unfortunately, cross-reactivity of acrylic monomers used in dentistry is not sufficiently mapped to enable selection of an appropriate compound for the sensitized person. Another important aspect is that product declarations of dental acrylic materials should show all acrylic compounds present in the products—even acrylic monomers/impurities with lower concentrations than 1%. This could help to select a product that the sensitized individual could use.

ChemInform Abstract: Phosphine-Catalyzed Dimerization of Activated Alkenes under Ambient and High Pressure Conditions.

Abstract Acrylic compounds dimerize under Morita–Baylis–Hillman conditions in the presence of soluble phosphines. Dimerization of β-substituted analogs may require high pressures. The process is selective and high yielding and affords densely functionalized products.

Rheological testing of p-tert-butylphenol epoxy–acrylic resin in the presence of reactive diluents

The rheological testing of synthesized para-tert-butylphenol epoxy–acrylic resin in the presence of reactive diluents based on epoxy–acrylic compounds of phenol, para-tert-butylphenol and para-nonylphenol was carried out with a “Rheotest 2” type viscometer. The synthesized resin, the tested reactive diluents, as well as the mixtures based on the resin and the reactive diluents, show non-Newtonian rheological behaviour of the pseudoplastic type. This behaviour can be explained by taking into consideration the possible interactions among the chains of the phenolic reactive diluents, and with the chain of the resin. These interactions can also be due to –OH phenolic groups. As a result, a false increase is registered in the molecular weight of the systems studied.

Chemo-enzymatic synthesis and characterization of graft copolymers from lignin and acrylic compounds.

Chemo-enzymatic initiation of graft copolymerization of acrylic compounds onto different technical lignosulfonates (LS) was compared to a Fenton-like system (ferrous ion, t-BHP). The enzyme tested was a phenoloxidase laccase (EC 1.10.3.2) from the white rot basidomycete Trametes versicolor. Most applied lignins were successfully grafted, resulting in a polymer yield of more than 90%. The effect of initiator concentration and the lignin/monomer ratio on the yield and M(w) of enzymatically grafted polymers were studied. The homopolymer proportion in the enzymatically produced grafts of Ca-LS and acrylic acid was 5 to 6x lower than those initiated by the Fenton-like reagent; no such differences were observed for Na-LS.

Phosphine-catalyzed dimerization of activated alkenes under ambient and high pressure conditions

Acrylic compounds dimerize under Morita–Baylis–Hillman conditions in the presence of soluble phosphines. Dimerization of β-substituted analogs may require high pressures. The process is selective and high yielding and affords densely functionalized products.

2,4-DIAMINO-1-THIA-3-AZABUTADIENES, INTERMEDIATES IN HETEROCYCLIC SYNTHESIS

2,4-Diamino-1-thia-3-azabutadienes 1 were studied. Methylation occured at sulfur and acylation at nitrogen bound to the 2 position. Alkylation by α-bromoketones gave rise to 2-amino-5-acylthiazoles. Upon treatment with acrylic dienophiles compounds 1 reacted either as diazadiene or as thiazadiene yielding tetrahydropyrimidinethiones or 6H-1,3-thiazines respectively.