Reaction Of Acrylate Research Articles

Exploiting the Base‐Triggered Thiol/Vinyl Ether Addition to Prepare Well‐Defined Microphase Separated Thermo‐Switchable Adhesives

AbstractSwitchable adhesives are materials of utmost importance due to their capability of having their adhesion/cohesion properties reversibly triggered upon stimuli, allowing on‐demand surface attaching/detaching. Still, several challenges mainly associated with complex uncontrolled chemical processes hinders their production. In this study, it is found that unexpectedly vinyl ethers are able to react with thiols in the presence of a catalytic concentration of base, which allows the preparation of well‐defined phase‐separated switchable adhesives. Indeed, these findings show that base‐catalyzed thiol‐acrylate and thiol‐vinyl ether are highly orthogonal, making the acrylate reaction faster. This is explored to react in the first stage thiols with acrylates in the presence of vinyl ethers to end‐cap all the oligomers with stable vinyl ethers and suppress undesirable disulfide formation. In a second stage the UV‐triggered thiol‐ene “click reaction” is carried out, forming the network. It is shown that the network prepared by this approach presents superior adhesion due to greater backbone length, a controlled crosslinking motif, and better‐defined microphase separation. Additionally, the adhesives made by this strategy are thermo‐switchable due to the temperature‐triggered base‐catalyzed thioether dynamic covalent character at 200 °C. Despite providing superior adhesive properties, the proposed technology endows scalable, thermo‐switchable, and O2‐resistant adhesives with huge industrialization potential.

Efficient and facile dual post-polymerization modification using acetoacetate-acrylate Michael addition

Post-polymerization modification (PPM) is a valuable strategy for achieving diversified functional polymers; nonetheless, the pursuit of achieving mild and efficient dual modification along the polymeric backbone remains as a challenge. In this work, the Michael addition reaction of acetoacetates and acrylates have been demonstrated as a robust PPM technique. The reversible addition-fragmentation chain transfer polymerization of commercially available 2-(acetoacetoxy)ethyl methacrylate provides a polymer scaffold with controlled molecular weight and acetoacetate groups. These pendant groups are capable of undergoing efficient double addition reactions with acrylates, leading to an increased density of functional moieties within the polymeric backbone. This PPM reaction exhibits unique advantages such as mild reaction conditions (at 40 °C), rapid kinetics (completion within 1 h), and high atom economy. Consequently, a series of polymers with tunable thermal stability, glass transition temperature, and hydrophilicity have been successfully synthesized. Applications have been demonstrated for both the synthesis of polymers exhibiting aggregation-induced luminescence and the preparation of luminescent materials with adjustable mechanical properties. This pioneering work unveils a robust post-polymerization modification technique, significantly advancing the synthesis of innovative functional polymers.

Synthesis of Trisubstituted Furans from Activated Alkenes by P(III)/P(V) Redox Cycling Catalysis.

The organocatalytic formation of an underrepresented family of trisubstituted and tetrasubstituted furans from activated alkenes and acyl chlorides is reported. In a reaction sequence based on P(III)/P(V) redox cycling catalysis, the cyclic phosphine catalysts react with diacylethenes or acyl acrylates in Michael addition, followed by acylation and either an intramolecular Wittig reaction or a ring closure reaction, liberating the furans. The formed phosphine oxides are reduced in situ by phenylsilane as a terminal reductant. In the first step, 12 diacylethenes were converted to the respective trisubstituted furans. The reaction of acyl acrylates showed a surprising, catalyst-dependent alternate reaction forming tetrasubstituted furans. Two additional methods were developed, giving 14 trisubstituted furans using a phospholene catalyst and an additional 6 tetrasubstituted furans using a phosphetane catalyst. This encompassed 19 newly described compounds.

Bio-based non-isocyanate poly(urea)-PEG hybrids for VOC-free waterborne dispersions and fast UV-curable film application

Poly(urethane)-acrylate hybrids are often used to yield high-performing fast UV-curable coatings thanks to their highly reactive acrylate moieties. However, they are usually manufactured from toxic and petro-based isocyanate (e.g. isophorone diisocyanate, hexamethylene diisocyanate) monomers and are dispersed in water using toxic volatile neutralization agent (e.g. triethylamine). To tackle those issues, hydrophobic and bio-based non-isocyanate poly(urea) (NIPUrea) blocks have been synthesized and coupled with hydrophilic poly(ethylene glycol) diacrylate (PEGdA) via aza-Michael reaction to yield VOC-free non-ionic waterborne NIPUrea-acrylate dispersions. Those amphiphilic NIPUrea-PEG hybrids enabled the development of low particle-size waterborne dispersions for fast UV curable films (curing time < 1 min) with high gel content (>98 %) and tunable mechanical properties.

Deconvoluting Substrates, Support, and Temperature Effects on Leaching and Deactivation of Pd Catalysts: An In Situ Study in Flow.

Leaching behavior of three different Pd heterogeneous catalysts (PdEnCat 30, FibreCat FC1001, and Pd/Al2O3) during the Heck reaction of iodobenzene and methyl acrylate, in the presence of triethylamine, was compared using a tandem flow reactor. While leaching was observed in all three cases, Pd/Al2O3 appeared to be the most robust, showing little/no leaching at ambient temperature. The leached Pd species also appear to display different catalytic activities. With a slight modification of the reactor, the leaching caused by individual components of the reaction mixture can be assessed separately. For the polymer-supported catalysts, triethylamine caused the largest amount of leaching, even at 30 °C. In contrast, the leaching from Pd/Al2O3 was observed only in the presence of iodobenzene at 90 °C. Variations in leaching behavior were ascribed to differences in Pd species and immobilization methods.

Study of size effect of palladium atoms as single-atom and clusters nanoparticle catalysts for Heck reactions

We reported a series of nitrogen-doped carbon-supported palladium (Pd) species with various sizes for the Heck reaction of iodobenzene and methyl acrylate. By precisely controlling the synthesis procedure, we have successfully synthesized a range of Pd-based catalysts, including single Pd atom, sub-nanometer Pd clusters (∼ 0.4 nm, and ∼1.6 nm), and Pd nanoparticles (∼5.8 nm and 10 nm). Remarkably, these catalysts exhibit a distinct size-dependent catalytic activity in the Heck reaction. In the case of the Heck reaction of 4‑methoxy-iodobenzene and methyl acrylate, the Pd-10 site demonstrated the highest site-specific turnover frequency (TOF), reaching 792.5 h−1. This performance is impressively 5.2 and 15.6 times superior to that of the Pd1 site (152 h-1) and Pd-10 site (50.6 h-1), respectively. Significantly better in the Heck reactions with other aryl halides were achieved with Pd-1.6/N-C (comprising of approximately 1.6 nm-sized Pd clusters), compared to those containing 10 nm-sized nanoparticles (Pd-10/N-C) or Pd1/N-C. These findings suggested that Pd clusters of around 1.6 nm may serve as the potential catalytic sites for the Heck reaction.

Synthetic Strategies toward Ortho-3-propanoate Substituted Aryl Phosphonates by Three-Component Coupling Reactions of Arynes, Phosphites, and Acrylates.

Mild, metal-free, and operationally simple three-component coupling reactions involving arynes, phosphites, and acrylates have been achieved. The reaction proceeded well with α- or β-substituted acrylates. Additionally, various functional groups were tolerated under these reaction conditions, resulting in diverse ortho-3-propanoate-substituted aryl phosphonates. Moreover, the reaction can be used to synthesize a range of organophosphorus compounds present in natural products, materials, and biologically active compounds.

Unprecedented Mo3S4 cluster-catalyzed radical C-C cross-coupling reactions of aryl alkynes and acrylates.

A new method for the generation of benzyl radicals from terminal aromatic alkynes has been developed, which allows the direct cross coupling with acrylate derivatives. Our additive-free protocol employs air-stable diamino Mo3S4 cubane-type cluster catalysts in the presence of hydrogen. A sulfur-centered cluster catalysis mechanism for benzyl radical formation is proposed based on catalytic and stoichiometric experiments. The process starts with the cluster hydrogen activation to form a bis(hydrosulfido) [Mo3(μ3-S)(μ-S)(μ-SH)2Cl3(dmen)3]+intermediate. The reaction of various aromatic terminal alkynes containing different functionalities with a series of acrylates affords the corresponding Giese-type radical addition products.

HYDROFORMYLATION OF METHYL ACRYLATE USING A PALLADIUM SCHIFF BASE CATALYST UNDER SYNGAS SOURCE

Hydroformylation of methyl acrylate can be carried out in a short time and without the use of syngas under microwave dielectric heating. We show that a Palladium Schiff base catalyst can control regioselectivity in heterogenous hydroformylation. Microwave irradiation, which produces greater yields in less reaction time and uses less energy than conventional heating systems, may carry out the hydroformylation reactions of the Methyl acrylate with greater efficiency and sustainability without using the CO and H2 cylinder. This method offers a hopeful prospect for a more sustainable future in chemical synthesis. Hydroformylation of Methyl acrylate using (PdL2)Cl2) (where L= N- (diphynylmethylide) Aniline (LA) and (E)-1-(2-methoxyphenyl)-N-phenylmethanimine (LB), as a catalyst at 120 oC for 20 minutes in the microwave and at 200 oC, 5 h in the conventional heating. This work demonstrates that methyl acrylates can be hydroformed in glyoxylic acid using a palladium catalyst system, producing the intended products, aldehydes, in outstanding yields and selectivities. Moreover, solventless synthesis using specific catalyst systems has improved catalytic performance compared to solvent-based reactions, attributed to higher reactant concentrations. Palladium complexes PdLA and PdLB gave excellent aldehyde yields in the microwave, 89 % (l/b ratio 96:4) and 86 % (95:5), respectively, over the conventional heating, which were analyzed by 1HNMR and GCMS spectroscopic techniques.

Excellence in Acrylation - Scope and Limitation of Glucosyl Imidazolium-coated Novozym 435 Catalyzed (Meth)acryl Ester Synthesis.

The incorporation of carbohydrate based ionic liquids as a support for Novozym 435 was previously studied by the authors for the acrylation of n-butanol as the target substrate, which was used as the foundation for the design of experiments. The combination of carbohydrate based ionic liquids and Novozym 435 remains a key aspect of this work. Building upon this, the reaction parameters were optimized for the Novozym catalyst. Substrate screening was performed to explore the scope and limitations of room temperature acrylation reactions. Herein, different alcohols and reaction conditions were screened extensively for the different acrylate products with yields of up to 99.9 % determined via gas chromatography (GC). Standard straight chain alcohols, 2-functionalized ethanol derivatives with electron donating and withdrawing groups, and more sterically challenging substrates were investigated over a broad concentration region. To further underline the applicability of the modified biocatalyst, two alcohols were converted with methacrylic acid. The presented method offers a greener pathway for acrylate synthesis, which eliminates the need for high reaction temperatures, strongly acidic catalysts and/or polymerization inhibitors as used in non-biocatalytic acrylate synthesis.

High-performance addition reaction of methyl acrylate and methanol for the preparation of Methyl 3-methoxypropionate on NiO/MgO catalyst

In this study, Methyl 3-methoxypropionate (MMP) was formed from the addition reaction of methyl acrylate (MA) and methanol using MO/MgO (M = Ce, Co, Ni) catalysts, which were prepared by a direct-mixing method. The prepared catalyst NiO/MgO shows good catalytic activity than that of the CeO/MgO and CoO/MgO under the same conditions. The characterization and catalytic activity evaluation indicate that the NiO content of NiO/MgO has a significant effect on the catalytic activity of the addition reaction by changing the acid-base properties of the catalyst. The synergistic effect of acidic and basic sites contributes to the addition reaction. The optimal reaction temperature and pressure for NiO/MgO on this addition reaction is 200 ℃ and 2 MPa, respectively (over 90% selectivity to MMP). The cycle test indicates that the NiO/MgO catalyst is highly recyclable.

Acrylates Polymerization on Covalent Plasma-Assisted Functionalized Graphene: A Route to Synthesize Hybrid Functional Materials.

The modification of the surface properties of graphene with polymers provides a method for expanding its scope into new applications as a hybrid material. Unfortunately, the chemical inertness of graphene hinders the covalent functionalization required to build them up. Developing new strategies to enhance the graphene chemical activity for efficient and stable functionalization, while preserving its electronic properties, is a major challenge. We here devise a covalent functionalization method that is clean, reproducible, scalable, and technologically relevant for the synthesis of a large-scale, substrate-supported graphene-polymer hybrid material. In a first step, hydrogen-assisted plasma activation of p-aminophenol (p-AP) linker molecules produces their stable and covalent attachment to large-area graphene. Second, an in situ radical polymerization reaction of 2-hydroxyethyl acrylate (HEA) is carried out on the functionalized surface, leading to a graphene-polymer hybrid functional material. The functionalization with a hydrophilic and soft polymer modifies the hydrophobicity of graphene and might enhance its biocompatibility. We have characterized these hybrid materials by atomic force microscopy (AFM), X-Ray photoelectron spectroscopy (XPS) and Raman spectroscopy and studied their electrical response, confirming that the graphene/p-AP/PHEA architecture is anchored covalently by the sp3 hybridization and controlled polymerization reaction on graphene, retaining its suitable electronic properties. Among all the possibilities, we assess the proof of concept of this graphene-based hybrid platform as a humidity sensor. An enhanced sensitivity is obtained in comparison with pristine graphene and related materials. This functional nanoarchitecture and the two-step strategy open up future potential applications in sensors, biomaterials, or biotechnology fields.

Insight into the Promotion Effect of Trace Pd Doping on the Catalytic Performance of Ag/Al2O3 for C3H6-SCR of NOx.

The mechanistic cause of the enhancement of the C3H6-SCR activity of Ag/Al2O3 by trace Pd doping and the corresponding structure-property relationship were investigated. Pd doping enhanced the water resistance of Ag/Al2O3 for C3H6-SCR by changing the reaction pathway. Under wet conditions, a series of in situ DRIFT studies indicated that the production of an active acetate intermediate on Ag/Al2O3 was suppressed during the partial oxidation of C3H6, while trace Pd doping promoted the formation of another active intermediate, an enolic species. Furthermore, a pathway for the formation of enolic species by the reaction of acrylate with hydroxyl species was proposed. DFT calculations revealed that the surface of Ag clusters was easily covered by hydroxyl in the presence of water vapor, which could inhibit the formation of acetates. Doping with Pd facilitated the activation of acrylate which might further react with hydroxyl species to form enolic species. These findings can be helpful for the future design of efficient HC-SCR catalysts.

Multicomponent Reaction of Aliphatic Organozinc Reagents, Acrylates and Acyl chlorides: Synthesis of α‐Substituted β‐Ketoesters

AbstractAn uncatalyzed three‐component reaction employing aliphatic organozinc reagents for the preparation of α‐substituted β‐ketoesters is described. This modular procedure, which relies on a formal conjugate addition/crossed‐Claisen domino reaction between an organozinc, an acrylate and an acyl chloride, allows the straightforward synthesis of the reaction products under mild conditions. The three‐component coupling can also be conducted from alkyl iodides, in an even more simple procedure. Experimental findings account for a probable polar concerted mechanism involving at least two organozinc compounds at the stage of the transition state.

A novel CO2 based UV-induced peelable adhesive for wafer dicing

Poly (propylene carbonate) diol with double-bonds on the side chains (PPCAGE) was synthesized form CO2, propylene oxide (PO), polyether diol (PPG) and allyl glycidyl ether (AGE). Then, three kinds of CO2 based polyurethane oligomers (PPCAGE-PU) (PPCAGE-PUA, PPCAGE-PUB and PPCAGE-IPDI, respectively) with different contents of double bond were prepared through the reaction of PPCAGE, isophorone diisocyanate (IPDI) and hydroxyethyl acrylate (HEA). The content of -NCO was adjusted by varying the ratio of -NCO terminated prepolymer and HEA. Acrylate copolymer with side double bonds and hydroxyl groups (GMA-PSA) was synthesized by the ring-opening reaction of glycidyl methacrylate (GMA) and acrylate copolymer (PSA) containing -COOH and -OH. CO2 based UV-induced peelable adhesive was prepared by mixing PPCAGE-PU, GMA-PSA, active diluent and photoinitiator. The structure of PPCAGE was confirmed by Fourier transform infrared (FT-IR) and nuclear magnetic resonance (1H NMR). The reaction of PPCAGE-PUB and GMA-PSA was monitored by FT-IR, companied by the titration of -NCO and epoxide. The molecular weight of PSA and GMA-PSA was determined by gel permeation chromatography (GPC). The surface morphology of the adhesive was observed by scanning electron microscopy (SEM). The viscoelasticity of adhesive was measured by real-time rheology. The 180° peel strength, micro-surface morphology, gel content, unsaturation conversion and glass transition temperature of UV-induced peelable adhesive were characterized. The results showed that the peel strength of adhesive was 17.82 N/25 mm before UV curing. After UV curing, the surface morphology changed from smooth to rough, the peel strength decreased to 0.08 N/25 mm and the modulus of the PSA increased due to the cross-linking. DSC results showed that the glass transition temperature increased after UV curing.

Enhancement in Heck reaction by SiC supported Pd nanoparticles under visible light irradiation

Heck reaction is one of the effective routes to form C-C bond, however the process still suffers problems from the separation and low-temperature activity of catalysts. Herein, Pd nanoparticles supported on SiC was prepared by a sample impregnation-reduction process. The Pd/SiC photocatalyst exhibited a high iodobenzene conversion of 99.6 % with 100 % selectivity to methyl cinnamate under visible light irradiation at 40 ℃. The excellent performance is due to the good light absorption ability of Pd/SiC and effective charge separation through Mott-Schottky junction between Pd and SiC. The electron-rich Pd nanoparticles are favorable to activate C-I bond of iodobenzene, thus enhancing the photocatalytic activity for Heck reaction of iodobenzene and methyl acrylate.

CD13 Remote review for final patch test reading: a virtual reality?

Abstract Patch test reading at day 7 is suggested in current national (British Association of Dermatologists 2017) and international (European Society of Contact Dermatitis 2015) guidelines to identify late positive reactions. Allergens most established with late reactions are metals, antibiotics, acrylates and preservatives (Viggiano T, Yiannias JA, Yang YW. A retrospective review of late delayed positive patch testing greater than day 8 at Mayo Clinic from 2001 to 2020. Dermatitis 2022; 33:411–16). We report a case of significantly delayed contact dermatitis to four acrylates and ethyl paraben in a 49-year-old immunocompetent woman. She was referred to the cutaneous allergy clinic for patch testing following a rash affecting the torso after application of a sunscreen during a sunny holiday. She reported historical skin irritation after the use of nail lacquer and at the site of a caesarean section wound that was closed with skin glue 14 years prior. Patch test reading at day 4 (96 h) was negative; positive reactions to ethyl paraben, 2-hydroxyethylmethacrylate and ethyl cyanoacrylate appeared at day 23 (552 h). Positive reactions to hexanediol diacrylate and triethylene glycol diacrylate appeared at day 31 (744 h). These were communicated to us by the patient via email, with photographs clearly showing the development of new positive reactions. Of note, there was no reaction to the sunscreen product, although ethyl paraben was identified in the ingredients list, as well as two acrylate-containing polymers. Sensitization from diagnostic patch testing carried out to accepted international guidelines is rare but can occur with some allergens such as strong sensitizers, including paraphenylenediamine. The allergens identified in our case are found commonly in everyday cosmetics, adhesives and preservatives, including some that the patient had identified previous exposure to. Acrylates are acknowledged for causing potential delayed positive reaction by day 8 (Viggiano et al.); one case report describes true allergic acrylate reaction in a dental worker after 5 weeks (Fowler JF Jr. Late patch test reaction to acrylates in a dental worker. Am J Contact Dermat 1999; 10:224–5). There are no established reports of late positive reactions to ethyl paraben. With increasing online resources, delayed reactions beyond day 7 can be established with patient-initiated remote review of photographs taken during and subsequent to patch testing appointments. This case highlights the importance of keeping channels open for patients to contact the cutaneous allergy team after the final in-person reading to ensure (very) late allergen reactions are not missed.

Spectral and photophysical characteristics of asymmetric polymethine dyes in polyurethane matrices

Effects of the polymer matrix polarity on the spectral and photophysical properties of asymmetric polymethine dyes were investigated. Asymmetrical cyanines of the LDS (laser dye styryl) series were used, which were introduced into elastic polyurethane matrices by an auxiliary solvent. Polymer media were synthesized by: a polyaddition reaction based on macrodiisocyanate from oligoethylene glycol adipinate, hexamethylene diisocyanate, trimethylolpropane, and a photopolymerization reaction of oligourethane acrylate with benzoin isobutyl ether. Polyurethane polarity influence on the absorption and luminescence band maxima, and the Stokes shift of the dye spectra was studied, and the obtained spectral parameters of dyes in the polymer matrices were compared with the corresponding characteristics of their ethanol solutions. The observed spectral peak positions of the absorption and luminescence bands, changes in the Stokes shift value for the LDS dyes in different environments indicated the presence of positive solvatochromism. The presented results demonstrated the possibility of the significant increase in photostability of asymmetric polymethine dyes in the polymer polyurethane matrix of high polarity, obtained by means of the polyaddition reaction.

NIR light triggered intracellular polymerization via nanoparticles containing acrylates prodrugs and azo-polymers for inhibiting cisplatin efflux for combined chemotherapy and immunotherapy

Despite the high clinical success of cisplatin, this compound is associated with insufficient intracellular uptake and quick excretion from cancer cells, resulting in poor drug efficacy. To overcome these limitations, herein, a nanoparticle formulation for efficient drug delivery and high therapeutic effect towards challenging cancer tumors by multimodal chemotherapy and immunotherapy is reported. The nanoparticles are generated upon self-assembly of a polymerizable Pt(IV) prodrug with axial acrylates, a near-infrared II polymer that can generate heat, and a thermosensitive polymer with azo bonds that can generate radicals upon exposure to heat. The nanoparticles are found with a higher cellular uptake than the molecular drug cisplatin. Upon exposure to irradiation at 1064 nm, the azo bonds are broken, and therapeutically active radicals as well as the Pt(IV) complex simultaneously released. Due to the presence of reactive acrylate moieties, the metal complex is able to undergo in-situ polymerization inside the cancer cells, resulting in the formation of a cross-linked polymeric network and therefore the retention of the cisplatin and reduction of the cisplatin efflux in the cancer cells, triggering cell death by a combination of apoptosis and immunogenic cell death. Based on these promising effects, the therapeutic efficiency is evaluated in a clinically highly challenging ovarian cancer patient-derived xenograft mouse model as well as an ID8 subcutaneous tumor-bearing C57BL/6 mouse model. This study reports on the first example of a nanoparticle delivery system with Pt(IV) prodrugs that can polymerize within cancer cells, thereby resulting in a decrease in cisplatin efflux, efficient DNA damage, and effective immunogenic response.

Activation of Mo2B Catalyst in the Epoxidation Reaction of α-Ethylallyl Ethyl Acrylate with tert-Butyl Hydroperoxide

The regularities of Mo2B catalyst activation in the epoxidation reaction of alfa-ethylallyl ethyl acrylate with tert-butyl hydroperoxide have been studied. It has been shown that the catalyst activation process is described by the Avrami-Erofeev topokinetic equation and includes two successive stages – the nucleation and formation of a new phase active in the epoxidation reaction. The formation of epoxy only occurs in the presence of the activated form of the catalyst. The effective and topochemical process constants have been calculated.