Methyl Acrylate Research Articles

Controllable modulation of acid-base properties and balance for promoting methyl acrylate production over CsMg-Zr/SiO2

Controllable modulation of acid-base properties and balance for promoting methyl acrylate production over CsMg-Zr/SiO2

In vitro validation of colon delivery of vitamin B2 through a food grade multi-unit particle system.

Colon target delivery of active ingredients is frequently applied in pharmaceutical products. However, in functional food and beverage applications, dietary supplements, and medical nutrition, formats targeting colonic delivery to improve human health are rare. Nevertheless, there is emerging evidence for beneficial effects of colonic delivered nutrients on gut microbiota and host health which increases the demand for sustainable food grade materials that are regulatory approved for application. In this paper, we describe a double layer coated multi-unit particle system (MUPS) with a diameter of approximately 730 microns consisting of food grade materials: shellac as outer layer, alginate as inner layer, cellulose as a core and riboflavin as active ingredient. The suitability of the MUPS for colonic delivery was tested in three well-established in vitro digestion and fermentation models: the USP Apparatus 3 and the TNO Intestinal Models 1 and 2 (TIM-1 and TIM-2). All systems confirmed the integrity of the MUPS under simulated upper gastrointestinal tract conditions with approximately 90% of the active ingredient being released under simulated ileal-colonic conditions. The TIM-2 model also showed the effects of riboflavin loaded MUPS on the microbiome composition with an increase in the production of short-chain fatty acids, acetate and butyrate. The results of these experiments provide a reliable basis for validation of this vitamin-loaded food grade MUPS in future human clinical trials. In addition, following the recent announcement of the European Commission to restrict intentionally added microplastics to products, the materials used in the described formulation offer an environmentally friendly alternative to often applied methyl acrylate based coatings.

Stereochemical Impacts on Acyclic Mechanochemical Carbon-Carbon Bond Activation.

The influence of stereochemistry on the mechanochemistry rate is studied using a new mechanophore based on a benzopinacol (BP) skeleton. Two sets of BP diastereomers, the meso R,S and the R,R/S,S were isolated, incorporated into the center of a poly(methyl acrylate), and their mechanical activation rate was measured in solution. Under mechanical stress, the central C-C bond in BP is cleaved, providing two independent benzophenone molecules with higher UV-absorption coefficient at 254 nm. Monitoring the reaction rate spectroscopically indicates that the chiral R,R/S,S enantiomers react ~1.4 fold faster compared to the meso R,S diastereomer. In-silico modeling indicates that a hydrogen bond between the syn hydroxyls in the R,R diastereomer becomes shorter with stress, reducing the maximal force required for C-C bond scission, while this bond is inexistent in the meso diastereomer, as the hydroxyl are anti to each other. Our results indicate that in polymer where free rotation around bonds is possible, non-covalent interactions between backbone substituents, which are affected by relative stereochemistry, can play a fundamental role in the mechanochemical stability of the polymer.

Stereochemical Impacts on Acyclic Mechanochemical Carbon‐Carbon Bond Activation

The influence of stereochemistry on the mechanochemistry rate is studied using a new mechanophore based on a benzopinacol (BP) skeleton. Two sets of BP diastereomers, the meso R,S and the R,R/S,S were isolated, incorporated into the center of a poly(methyl acrylate), and their mechanical activation rate was measured in solution. Under mechanical stress, the central C‐C bond in BP is cleaved, providing two independent benzophenone molecules with higher UV‐absorption coefficient at 254 nm. Monitoring the reaction rate spectroscopically indicates that the chiral R,R/S,S enantiomers react ~1.4 fold faster compared to the meso R,S diastereomer. In‐silico modeling indicates that a hydrogen bond between the syn hydroxyls in the R,R diastereomer becomes shorter with stress, reducing the maximal force required for C‐C bond scission, while this bond is inexistent in the meso diastereomer, as the hydroxyl are anti to each other. Our results indicate that in polymer where free rotation around bonds is possible, non‐covalent interactions between backbone substituents, which are affected by relative stereochemistry, can play a fundamental role in the mechanochemical stability of the polymer.

Riboflavin‐Catalyzed Photoinduced Atom Transfer Radical Polymerization

AbstractThe photoATRP of methyl acrylate (MA) is investigated using riboflavin (RF) and CuBr2/Me6TREN as a dual catalyst system under green LED irradiation (λ ≈ 525 nm). Both RF and CuBr2/Me6TREN enhanced oxygen tolerance, enabling effective ATRP in the presence of residual oxygen. High molar mass polymers (up to Mn ≈ 129 000 g·mol−1) with low dispersity (Đ ≤ 1.16) are prepared, and chain‐end fidelity is confirmed through successful chain extension. The molecular masses of the obtained polymer increased linearly with conversion and showed high initiation efficiency. Mechanistic studies by laser flash photolysis reveal that the predominant activator generation mechanism is reductive quenching of RF by Me6TREN (83%, under [CuBr2]/[Me6TREN] = 1/3 condition), supported by polymerization kinetics and thermodynamic calculations.

Second Generation Zwitterionic Aza‐Diarylethene: Photoreversible CN Bond Formation, Three‐State Photoswitching, Thermal Energy Release, and Facile Photoinitiation of Polymerization

Diarylethenes are a well‐studied and optimized class of photoswitches with a wide range of applications, including data storage, smart materials, or photocontrolled catalysis and biological processes. Most recently, aza‐diarylethenes have been developed in which carbon‐carbon bond connections are replaced by carbon‐nitrogen connections. This structural elaboration opens an entire new structure and property space expanding versatility and applicability of diarylethenes. In this work, we present the second generation of zwitterionic aza‐diarylethenes, which finally allows for fully reversible photoswitching and precise control over all three switching states. High‐yielding photoswitching between the neutral open form and a zwitterionic Z isomer is achieved with two different wavelengths of light. The third zwitterionic E isomeric state can be reached up to 87% upon irradiation with a third wavelength. Its high energy content of >10 kcal/mol can be released thermally by deliberate solvent change as trigger mechanism, rendering aza‐diarylethenes into interesting candidates for molecular solar thermal energy storage (MOST) applications. The third state further serves as locking state, allowing to toggle light‐responsiveness reversibly between thermally labile and thermally stable switching. Further, irradiation of the zwitterionic states leads to highly efficient photopolymerization of methyl acrylate (MA), directly harnessing the unleashed chemical reactivity of aza‐diarylethene in materials applications.

Second Generation Zwitterionic Aza-Diarylethene: Photoreversible CN Bond Formation, Three-State Photoswitching, Thermal Energy Release, and Facile Photoinitiation of Polymerization.

Diarylethenes are a well-studied and optimized class of photoswitches with a wide range of applications, including data storage, smart materials, or photocontrolled catalysis and biological processes. Most recently, aza-diarylethenes have been developed in which carbon-carbon bond connections are replaced by carbon-nitrogen connections. This structural elaboration opens an entire new structure and property space expanding versatility and applicability of diarylethenes. In this work, we present the second generation of zwitterionic aza-diarylethenes, which finally allows for fully reversible photoswitching and precise control over all three switching states. High-yielding photoswitching between the neutral open form and a zwitterionicZisomer is achieved with two different wavelengths of light. The third zwitterionicEisomeric state can be reached up to 87% upon irradiation with a third wavelength. Its high energy content of >10 kcal/mol can be released thermally by deliberate solvent change as trigger mechanism, rendering aza-diarylethenes into interesting candidates for molecular solar thermal energystorage (MOST) applications. The third state further serves as locking state, allowing to toggle light-responsiveness reversibly between thermally labile and thermally stable switching. Further, irradiation of the zwitterionic states leads to highly efficient photopolymerization of methyl acrylate (MA),directly harnessing the unleashed chemical reactivity of aza-diarylethene in materials applications.

One‐Stone‐For‐Three‐Birds Strategy Using a Fullerene Modifier for Efficient and Stable Inverted Perovskite Solar Cells

AbstractThe electron extraction from perovskite/C60 interface plays a crucial role in influencing the photovoltaic performance of inverted perovskite solar cells (PSCs). Here, we develop a one‐stone‐for‐three‐birds strategy via employing a novel fullerene derivative bearing triple methyl acrylate groups (denoted as C60‐TMA) as a multifunctional interfacial layer to optimize electron extraction at the perovskite/C60 interface. It is found that the C60‐TMA not only passivates surface defects of perovskite via coordination interactions between C=O groups and Pb2+ cations but also bridge electron transfer between perovskite and C60. Moreover, it effectively induces the secondary grain growth of the perovskite film through strong bonding effect, and this phenomenon has never been observed in prior art reports on fullerene related studies. The combination of the above three upgrades enables improved perovskite film quality with increased grain size and enhanced crystallinity. With these advantages, C60‐TMA treated PSC devices exhibit a much higher power conversion efficiency (PCE) of 24.89 % than the control devices (23.66 %). Besides, C60‐TMA benefits improved thermal stability of PSC devices, retaining over 90 % of its initial efficiency after aging at 85 °C for 1200 h, primarily due to the reinforced interfacial interactions and improved perovskite film quality.

One-Stone-For-Three-Birds Strategy Using a Fullerene Modifier for Efficient and Stable Inverted Perovskite Solar Cells.

The electron extraction from perovskite/C60 interface plays a crucial role in influencing the photovoltaic performance of inverted perovskite solar cells (PSCs). Here, we develop a one-stone-for-three-birds strategy via employing a novel fullerene derivative bearing triple methyl acrylate groups (denoted as C60-TMA) as a multifunctional interfacial layer to optimize electron extraction at the perovskite/C60 interface. It is found that the C60-TMA not only passivates surface defects of perovskite via coordination interactions between C=O groups and Pb2+ cations but also bridge electron transfer between perovskite and C60. Moreover, it effectively induces the secondary grain growth of the perovskite film through strong bonding effect, and this phenomenon has never been observed in prior art reports on fullerene related studies. The combination of the above three upgrades enables improved perovskite film quality with increased grain size and enhanced crystallinity. With these advantages, C60-TMA treated PSC devices exhibit a much higher power conversion efficiency (PCE) of 24.89 % than the control devices (23.66 %). Besides, C60-TMA benefits improved thermal stability of PSC devices, retaining over 90 % of its initial efficiency after aging at 85 °C for 1200 h, primarily due to the reinforced interfacial interactions and improved perovskite film quality.

Three-Component Syntheses of Functionalized Selenocyanates

AbstractA metal-free Meerwein-type arylation protocol of α,β-unsaturated compounds is reported. 4-Aryl-3-selenocyanatobutan-2-ones, methyl 3-aryl-2-selenocyanatopropanoates, 3-aryl-2-selenocyanatopropanenitriles, and 1-aryl-2-phenyl-2-selenocyanatoethanes were prepared by a selenocyanatoarylation reaction from easily available arenediazonium tetrafluoroborates, potassium selenocyanate, and methyl vinyl ketone, methyl acrylate, acrylonitrile, or styrene, respectively, in 39–84% yields. The reaction proceeds smoothly and quickly under mild reaction conditions. The reaction can be scaled to the gram scale. A mechanism for this reaction is proposed.

Using higher rates of stabilization of a wet-spun pan fibre to understand the effect of microstructure on the tensile and compressive properties of carbon fibre

The transformation of a polyacrylonitrile (PAN) precursor fibre into carbon fibre using varying stabilization times during carbon fibre manufacture is presented in this work. The wet-spun precursor fibre is a specifically designed PAN co-polymer made up of acrylonitrile, methyl acrylate and 3 wt% itaconic acid. The residence or stabilization times in the oxidation ovens are varied from 32, 64 and 96 min, enabling investigation of the impact upon microstructure upon tensile and compressive properties. Using a continuous pilot scale carbonization line for faster cyclization and dehydrogenation, the precursor fibres exhibited lower oxygen uptake contributing to the formation of a less dense and more amorphous carbon fibre. Synchrotron based SAXS-WAXS characterisation and Raman spectroscopy of the carbon fibre microstructure displays lower orientation and crystallinity, with higher void concentration. This led to lower electrical conductivity, lower tensile strength (19 %) but higher compressive strength (27 %) when reducing stabilisation times from 96 to 32 min.

Nonlinear optical parameters and electronic properties of plasma polymerized methyl acrylate thin films

Plasma polymerized methyl acrylate (PPMA) thin films were fabricated on a borosilicate glass substrate at a plasma power of 28 W to study nonlinear optical parameters and electronic properties. X-ray Diffraction analysis confirmed the amorphous nature of the PPMA films, while Attenuated total reflectance Fourier transform infrared spectroscopy indicated monomer fragmentation due to plasma polymerization. Field emission scanning electron microscope images of the films display a water wave-like structure. PPMA films demonstrated thermal stability up to approximately 574 K in both N2 and air environments. The values of direct band gap energies increase from 3.30 to 3.41 eV with increasing film thicknesses, whereas the Urbach energy values show in an opposite manner. The Wemple-DiDomenico model was employed to analyze both the oscillator energies ranging from 5.54 to 6.44 eV and the dispersion energies ranging from 10.56 to 12.89 eV. The static linear refractive index showed typical dispersion behavior, with film thickness conforming to Moss's rule. The nonlinear refractive index and 2nd and 3rd order nonlinear susceptibilities decrease with increasing the studied films. The lattice dielectric constant values exceeded the high-frequency dielectric constant, indicating the presence of lattice vibrations and free carriers. Electronic parameters are fluctuating with increasing film thickness. The observed changes in nonlinear optical parameters and electronic properties highlight the potential of PPMA films for applications in photovoltaic and optoelectronics.

Ultrasound-assisted synthesis of methyl acrylate using Amberlyst-15 catalyst: optimization using response surface method

Ultrasound-assisted synthesis of methyl acrylate was performed in a solvent-free ultrasound batch reactor using acid ion exchange resin (amberlyst-15) as a heterogeneous catalyst. Influence of different reaction parameters such as temperature (40-70°C), alcohol to acid mole ratio (2-8), catalyst loading (0-10 % w/w), and addition of molecular sieves (0-8%), ultrasound power (0-120W), and duty cycle (20-80%) on the activity of reaction were investigated through one parameter at a time. Further, four significant parameters were optimized using response surface methodology using a central composite design. The maximum conversion of acrylic acid 61.02 %, was obtained at optimum reaction conditions at 61°C reaction temperature, 6.5 alcohol to acid mole ratio, 7.85% catalyst loading, and 60% ultrasound duty cycle. The equilibrium conversion improved from 29.2% to 61.02%, with a significant decrease in reaction time as compared to the conventional approach.

Magnetic graphene oxide nanosheets with amidoamine dendronized crosslinks for dual pH and redox-sensitive doxorubicin delivery

Delivering anticancer drugs to the appropriate site within the body poses a critical challenge in cancer treatment with chemotherapeutic agents like doxorubicin (DOX). Magnetic graphene oxide (GO) nanosheets with generation 1 (G1) amidoamine-dendronized crosslinks were developed by coupling cystamine-functionalized GO nanosheets with Fe3O4 nanoparticles modified with primary amine and methyl acrylate. These magnetic GO nanosheets were loaded with DOX to create a dual pH- and redox-responsive delivery system for cancer chemotherapy. The prepared magnetic nanosheets underwent characterization using FTIR, XRD, DLS, VSM, FE-SEM, and TEM. Physical DOX adsorption was evaluated using various isotherms, including Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich. The in-vitro release profiles of DOX from the magnetic nanosheets were studied under different pH conditions, with and without glutathione (GSH), and the drug release data were fitted with various kinetic models. Additionally, an MTT assay was employed to assess the compatibility and antitumor activity of DOX-loaded magnetic nanosheets in the HepG2 cell line. The results showed that the maximum drug loading was 13.1% (w/w) at a drug/carrier ratio of 1. Without GSH addition, the maximum drug release after 10 days was only 17.9% and 24.1% at pH 7.4 and 5.3, respectively. However, in the presence of GSH, the maximum drug release reached 51.7% and 64.8% at pH 7.4 and 5.3, respectively. Finally, the research findings suggest that the magnetic nanosheets exhibited pH- and redox-stimuli drug release, high biocompatibility, and superior antitumor activity compared to free DOX.

Efficient Uranium Removal from Aqueous Solutions Using Silica-Based Adsorbents Functionalized with Various Polyamines.

With the rapid development of nuclear energy, the contamination of environmental water systems by uranium has become a significant threat to human health. To efficiently remove uranium from these systems, three types of silica-based polyamine resins-SiPMA-DETA (SiPMA: silica/poly methyl acrylate; DETA: diethylenetriamine), SiPMA-TETA (TETA: triethylenetetramine), and SiPMA-TEPA (TEPA: tetraethylenepentamine)-were successfully prepared, characterized, and evaluated in batch experiments. Characterization results showed that the silica-based polyamine resins were successfully prepared, and they exhibited a uniform shape and high specific surface area. SiPMA-DETA, SiPMA-TETA, and SiPMA-TEPA had nitrogen contents of 4.08%, 3.72%, and 4.26%, respectively. Batch experiments indicated that these adsorbents could efficiently remove uranium from aqueous solutions with a pH of 5-9. The adsorption kinetics of U(VI) were consistent with the pseudo-second-order model, indicating that the adsorption process was chemisorption and that adsorption equilibrium was achieved within 10 min. SiPMA-TEPA, with the longest polyamine chain, exhibited the highest adsorption capacity (>198.95 mg/g), while SiPMA-DETA, with the shortest polyamine chain, demonstrated the highest U(VI) adsorption efficiency (83%) with 100 mM Na2SO4. SiPMA-TEPA still removed over 90% of U(VI) from river water and tap water. The spectral analysis revealed that the N-containing functional groups on the ligand were bound to anionic uranium-carbonate species and possibly contributed to the adsorption efficiency. In general, this work presents three effective adsorbents for removing uranium from environmental water systems and thus significantly contributes to the field of environmental protection.

Dual-Functional TiO2/SiO2@Poly(Hexadecyl Methacrylate-co-Butyl Methacrylate-co-Methyl Acrylate) Composites: Nanointegrated Enhancements in Oil Absorption and High-Efficiency Emulsion Interface Demulsification

Our research described in this report introduces a multifunctional composite resin, TiO2/SiO2@poly(hexadecyl methacrylate-co-butyl methacrylate-co-methyl acrylate), synthesized to enhance oil absorption and demulsification for oily wastewater treatment. By incorporating hydrophobically modified nano-titanium dioxide (nano-TiO2) and nano-silicon dioxide (nano-SiO2) into a polyacrylate resin through suspension polymerization, we aimed to overcome the limitations of traditional oil absorbent resins. The resin’s formulation included hexadecyl methacrylate, butyl methacrylate, and methyl acrylate. Characterization was conducted through measurements of contact angle, Fourier-transform infrared spectroscopy, scanning electron microscopy, and Brunauer–Emmett–Teller surface area analyses. The study meticulously optimized the chemical synthesis conditions, focusing on the amount of monomer, initiator and crosslinker, which are crucial for the polymerization reaction. Additionally, the physical parameters, such as the particle size and quantity of the nano-materials, were carefully controlled to achieve the desired material properties. The inclusion of nano-TiO2 and nano-SiO2 significantly enriched the resin’s porous structure, boosting its oil absorption ratios for oil in various solvents, notably enhancing stability and recyclability. The resin exhibited superior oil absorption capacities (e.g. 54.7 g/g for trichloromethane) and improved emulsion separation efficiency (e.g. 98.10% for trichloromethane emulsions), marking a substantial advancement in materials for environmental remediation applications.

Photoactivated Reactions without Traditional Photocatalysts: Electron-Donor Complexation of 1,2,3-Triazoles Initiates Denitrogenative Transformations.

We present a set of visible-light-promoted denitrogenative transformations of 1,2,3-triazoles that generate high product yields without the use of a traditional, external photocatalyst, with the reaction viable for both benzotriazole and benzotriazinone. Mechanistic studies using UV-vis absorption, 1H NMR spectroscopy, and density functional theory indicate that these reactions are initiated by an electron donor-acceptor (EDA) complex which forms between N,N-diisopropylethylamine (DIPEA) and the 1,2,3-triazole. A comprehensive analysis of how irradiation wavelength impacts reactivity was obtained using an online photochemical reactor coupled mass spectrometer, indicating a lack of correlation between absorptivity and photoreactivity for the reaction between benzotriazinone and methyl acrylate. The reaction was photoinitiated by light-emitting diodes (LEDs) at wavelengths longer than 400 nm, which is unexpected on the basis of solely the absorption spectra of the starting materials.

Direct synthesis of polar functionalized linear low density polyethylene (LLDPE) using slow-chain-walking palladium catalysts

Linear low-density polyethylene (LLDPE) is the most widely produced type of polyethylene resin. In this work, we detailed the synthesis and analysis of two bulky α-diimine Pd(II) complexes. These Pd(II) complexes can efficiently synthesize LLDPE-type polyethylene materials (ρ = 0.91–0.93 g/cm3) through ethylene slow-chain-walking polymerization. More interestingly, benefiting from the cationic bulky Pd(II) complexes, polar-functionalized LLDPEs (ρ = 0.91–0.92 g/cm3) are also produced by copolymerization of ethylene with various polar monomers such as 10-methyl undecanoate, methyl acrylate, 10-undecenoic acid. The copolymerization maintains the slow-chain-walking polymerization feature, resulting in a polar copolymer with a high melting point and low branching density. The results of 13C NMR spectral also reveal that polar groups are mainly located at the end of the branches in polar-functionalized LLDPEs.

PEG-assisted synthesis of highly dispersed Cs/Zr-SiO2 catalyst for aldol condensation of methyl acetate with formaldehyde

The dispersion of active sites plays an imperative role in the promotion of catalytic performance on methyl acrylate synthesis via direct vaporous aldol condensation. Herein, a novel PEG-assisted impregnation method was proposed to synthesize Cs/Zr-SiO2 catalyst with high dispersion of acid and base sites. A series of characterization techniques including NMR, TEM, physical N2 adsorption isotherms, XRD, XPS, NH3-/CO2-TPD, and Py-IR were used to investigate the physico-chemical properties of these prepared catalyst series. The introduction of PEG improved the specific surface area, dispersion of active sites, and density of acid and base sites, resulting in superior catalytic performance of Cs/PEG@Zr-SiO2 by comparison with that of Cs/SiO2 and Cs/Zr-SiO2. The kinetic experiments revealed that the activation energy of aldol condensation was 80.8 kJ/mol over the Cs/PEG@Zr-SiO2 catalyst. The deactivation behavior derived from carbon deposition was discovered, and the spent catalyst could be regenerated by simple thermal treatment.

Synthesis and characterization of mesoporous silicate as core and low generation polyamidoamine dendrimer as shell for delivery of 5-fluorouracil from their nano complex

Modern nanomedicine delivers drugs to malfunctioning cells. Several synthetic processes can change the shape, particle size, polydispersity index, surface area, and porosity of mesoporous silica nanoparticles (MSNs). Polyamidoamine (PAMAM) dendrimers are attractive polymers with circular forms, uniform distribution, well-structured branching, internal cavities, and surface terminal groups. The objective of this study is to deliver 5-fluorouracil (5-FU) as passive targeting to carcinogen cells via MSN-PAMAM-G3 nanoparticles. This study involved the direct and adaptable synthesis of MSN as the core vehicle, together with third-generation PAMAM dendrimers as the vehicle shell, with the goal of delivering the 5-FU in a targeted and controllable manner. Tetraethyl orthosilicate (TEOS) and cetyltrimethylammonium bromide (CTAB) are used as templates to make the center nanoparticle. Methyl acrylate (MA) and ethylenediamine (EDA) are monomers that cause the formation of branches in PAMAM. The obtained particles were fully characterized in terms of particle size, polydispersity index, zeta potential, thermal behavior, morphology, pore diameter, pore volume, and specific surface area. The particle size of MSN-PAMAM-G3s showed around 187.71 ± 3.97 nm, with a polydispersity index of 0.17 ± 0.01 and zeta potential of 32.17 ± 1.30 mV. By reducing the ratio of drug to vehicle from 1 to 0.25, a significant increase in the EE% of 5-FU from 21.36 ± 0.70 to 43.12 ± 0.67 was observed. The release of 5-FU from the vehicle (5-FU@MSN and 5-FU@MSN-PAMAM-G3) was shown to be considerably higher in an acidic medium (pH = 5.5) in comparison to a neutral medium (pH = 7.4) (P-value<0.05). Furthermore, in both acidic and neutral conditions, 5-FU release was sustained from the vehicle rather than the 5-FU solution. Our research revealed that the MSN-PAMAM-G3 nanoparticles effectively regulated the encapsulation and release of 5-FU, providing pH-sensitive and sustained medication delivery. It is asserted that this nanocarrier has the potential to effectively deliver 5-FU to cancer cells.