114512-63-9Relevant academic research and scientific papers
Homogeneous catalysis by cationic palladium complexes. Precision catalysis in the carbonylation of alkynes
Drent, E.,Arnoldy, P.,Budzelaar, P. H. M.
, p. 57 - 64 (1994)
A class of highly efficient homogeneous palladium cationic catalysts has been developed for the carbonylation of alkynes.An interesting application is the selective production of methyl methacrylate by methoxycarbonylation of propyne.The essential feature of the new catalyst systems is that they are formed by the combination of a ligand containing a 2-pyridylphosphine moiety with a palladium(II) species and a proton source containing weakly coordinating anions.High turnover numbers of more than 40 000 mol/(mol Pd h) and selectivities to methyl methacrylate of up to 99.95percent can be obtained under mild conditions.It is hypothesized that the 2-pyridylphosphine ligand plays an essential role both as a chelating P-N ligand in the selectivity-determining step and as a mono-coordinated ligand in the protonolysis step of the catalytic cycle.Key words: Palladium; Catalysis; Carbonylation; Alkyne; Methyl methacrylate; 2-Pyridylphosphine
Influence of Polar α Substituents in the Gas-Phase Pyrolysis Kinetics of Tertiary Chlorides. Correlation of Alkyl and Polar Groups
Chucani, Gabriel,Rotinov, Alexandra,Martin, Ignacio,Avila, Irama,Dominguez, Rosa M.
, p. 4134 - 4137 (1985)
The kinetics of the gas-phase pyrolysis of several polar α-substituted tertiary chlorides were determined in a static system over the temperature range of 339.5-420.1 deg C and the pressure range of 46-221 torr.The reactions in seasoned vessels and in the presence of a free-radical suppressor, are homogeneous and unimolecular and follow a first-order rate low.The variation of the rate coefficients with temperature is given by the following Arrhenius equations: for 1,2-dichloro-2-methylpropane, log k1 (s-1) = (14.29 +/- 0.53) - (207.6 +/- 6.4) kJ mol-1 (2.303RT)-1; for 2,2-dichloropropane, log k1 (s-1) = (12.88 +/- 0.53) - (199.0 +/- 6.5) kJ mol-1 (2.303RT)-1; for methyl 2-chloro-2-methylpropionate, log k1 (s-1) = (13.81 +/- 0.26) - (215.2 +/- 3.3) kJ mol-1 (2.303RT)-1.The log krel of polar α substituents against the polar substituent constant ?* values give an approximate straight line with ρ* = -0.73, correlation coefficient r = 0.912, and intercept = -0.194 at 300 deg C.This slope inflects at the point where ?*(CH3) = 0.00 with another reported very good straight line derived by plotting log k/k0 vs. ?* values for 2-chloro-2-alkylpropane pyrolyses (ρ* = -4.75, r = 0.993, and intercept = 0.047 at 300 deg C).The present results has been rationalized, as before, in terms of a slight alteration in the polarity of the transition state due to changes in electronic transmission at the carbon reaction center.
Multicatalytic Transformation of (Meth)acrylic Acids: a One-Pot Approach to Biobased Poly(meth)acrylates
Fouilloux, Hugo,Placet, Vincent,Qiang, Wei,Robert, Carine,Thomas, Christophe M.
, p. 19374 - 19382 (2021)
Shifting from petrochemical feedstocks to renewable resources can address some of the environmental issues associated with petrochemical extraction and make plastics production sustainable. Therefore, there is a growing interest in selective methods for transforming abundant renewable feedstocks into monomers suitable for polymer production. Reported herein are one-pot catalytic systems, that are active, productive, and selective under mild conditions for the synthesis of copolymers from renewable materials. Each system allows for anhydride formation, alcohol acylation and/or acid esterification, as well as polymerization of the formed (meth)acrylates, providing direct access to a new library of unique poly(meth)acrylates.
Reaction of Methyl Propionate with Methylal over V-Si-P Ternary Oxide Catalysts
Al, Mamoru
, p. 3722 - 3724 (1990)
The vapor-phase aldol condensation of methyl propionate with formaldehyde was performed using methylal as the source of formaldehyde.The main products were methyl methacrylate and methacrylic acid.The one-pass yield of methyl methacrylate plus methacrylic acid on methylal basis reached 53 molpercent at a methyl propionate/methylal molar ratio of 2 over the V-Si-P oxide with an atomic ratio of 1:16:3.2.
COUPLING REACTION BETWEEN METHYLPROPIONATE AND METHANOL TO FORM METHYLMETHACRYLATE OVER METAL ION-CONTAINED MAGNESIUM OXIDE CATALYSTS
Ueda, Wataru,Kurokawa, Hideki,Moro-Oka, Yoshihiko,Ikawa, Tsuneo
, p. 819 - 820 (1985)
Solid-base catalyst, MgO modified by metal ion promoted the cross-coupling reaction between methylpropionate and methanol to give methylmethacrylate. 65percent selectivity to methylmethacrylate was attained by using 16.7 wtpercent Mn-MgO catalyst at 400 d
Uncovering the mechanism of homogeneous methyl methacrylate formation with P,N chelating ligands and palladium: Favored reaction channels and selectivities
Crawford, L. Ellis,Cole-Hamilton, David J.,Bühl, Michael
, p. 438 - 449 (2015)
The catalytic alkoxycarbonylation of alkynes via palladium and P,N ligands, studied through a prototypical reaction involving propyne methoxycarbonylation yielding methyl methacrylate, has been explored at the B3PW91-D3/PCM level of density functional theory. Four different reaction routes have been probed in detail, spanning those involving one or two hemilabile P,N ligands and either hydride or carbomethoxy mechanisms. The cycle that is both energetically most plausible and congruent with experimental data involves Pd(0) and two P,N ligands acting cocatalytically in turn to shuffle protons via both protonation and deprotonation reactions. Other mechanisms proposed in the literature can be discounted because they would lead to insurmountable barriers or incorrect selectivities. For the preferred mechanism, the P,N ligand is found to be crucial in determining the strong regioselectivity and intrinsically controls the overall turnover of the catalytic cycle with moderate barriers (ΔGa§§ of 20.1 to 22.9 kcal/mol) predicted. Furthermore, the necessary acidic conditions are rationalized via a potential dicationic channel.
VINYLATION OF METHYL ACETATE AND METHYL PROPIONATE WITH METHANOL IN THE PRESENCE OF OXYGEN ON METAL ION-EXCHANGED FORMS OF FLUORO TETRASILICIC MICA
Wang, Fey-long,Ueda, Wataru,Morikawa, Yutaka,Ikawa, Tsuneo
, p. 281 - 282 (1989)
Among metal ion-exchanged forms of fluoro tetrasilicic mica (M-TSM's), Ti(IV)-TSM showed the highest catalytic activity at 350 deg C for the vinylation of esters with methanol in the presence of oxygen.The values of selectivity for the vinylation of methyl acetate to methyl acrylate and that of methyl propionate to methyl methacrylate attained 87 and 64percent, respectively.
Synthesis of methyl methacrylate by aldol condensation of methyl propionate with formaldehyde over acid-base bifunctional catalysts
Li, Bin,Yan, Ruiyi,Wang, Lei,Diao, Yanyan,Li, Zengxi,Zhang, Suojiang
, p. 829 - 838 (2013)
Supported cesium catalysts with various carriers (SiO2, Al 2O3, TiO2, MgO) were prepared and characterized by X-ray diffraction, BET nitrogen adsorption-desorption, NH3 and CO2-TPD methods and thermogravimetric analysis. Experimental results showed that the Zr-Mg-Cs/SiO2 catalyst exhibited moderate activity for aldol condensation of methyl propionate with formaldehyde (FA) to produce methyl methacrylate. Though the activity of Zr-Mg-Cs/SiO2 catalyst decreased with the time-on-stream, the deactivated catalyst was completely regenerated by calcination. The catalyst was regenerated 16 times and total operation time was over 500 h, its activity was identical with that of the fresh catalyst. Graphical Abstract: Gas aldol condensation reaction of methyl propionate with FA to produce MMA is an environmentally friendly technology; it doesn't need toxic raw materials. Cesium-impregnated silica exhibited better catalytic activity and high selectivity for this reaction, and this catalyst had good reusability and long cycle life. So it is a promising catalyst for industrial application. [Figure not available: see fulltext.]
Gas-Phase Pyrolysis Kinetics of 2-Substituted-2-Propyl Acetates. Effect of Substituents on the α-Carbon of Tertiary Acetates
Martin, Ignacio,Chuchani, Gabriel,Avila, Irama,Rotinov, Alexandra,Olmos, Rolando
, p. 9 - 11 (1980)
Three 2-substituted-2-propyl acetates undergo a homogeneous, first-order, unimolecular elimination in the gas phase at temperatures from 230 to 340 deg C and pressures from 56 to 210 mmHg.The rate constants are expressible by the Arrhenius equation: for 2,3,3-trimethyl-2-butyl acetate, log k (s-1) = (14.40 +/- 0.49) - (171.5 +/- 4.6) kJ mol-1 (2.303RT)-1; for α-acetoxyisobutyronitrile, log k (s-1) = (14.45 +/- 0.82) - (198.7 +/- 8.8) kJ mol-1 (2.303RT)-1; for methyl α-acetoxyisobutyrate, log k (s-1) = (12.53 +/- 0.32) - (176.1 +/- 3.6) kJ mol-1 (2.303RT)-1.The Taft correlation for the pyrolyses of tertiary esters with substituents on the α-carbon is projected and discussed.Many of these substituents enhance the elimination by steric accelaration.
Oxidative Esterification of Methacrolein to Methyl Methacrylate over Gold Nanoparticles on Hydroxyapatite
Gao, Jun,Fan, Guoli,Yang, Lan,Cao, Xinzhong,Zhang, Peng,Li, Feng
, p. 1230 - 1241 (2017)
The catalytic production of methyl methacrylate through the direct oxidative esterification of methacrolein is important in terms of green chemistry and sustainable development. In the present work, Au nanoparticles supported on three needle-like, lamella-like, and rodlike hydroxyapatites were synthesized. We demonstrated that needle-like hydroxyapatite could facilitate the higher dispersion of Au species because of its high specific surface area, and the strong interaction between the Au nanoparticles and the support resulted in the formation of more surface defects because of the existence of partially encapsulated Au particles by the needle-like hydroxyapatite. The surface defects were related closely to the generation of strong basic sites. Compared with the other two materials, the Au supported on the needle-like hydroxyapatite catalyst, which had a large amount of surface acid–base sites, exhibited a much higher catalytic activity and selectivity to methyl methacrylate in the direct oxidative esterification of methacrolein with methanol under mild reaction conditions (i.e., ambient pressure, low reaction temperature of 70 °C, and low methanol/aldehyde ratio of 8:1). The superior catalytic performance of the Au supported on needle-like hydroxyapatite catalyst was attributable to a cooperative effect between abundant acid–base sites for the preferential chemisorption of methacrolein and highly dispersed active Au species for the favorable formation of β-hydride and oxygen activation. The present findings open a new and promising route for the practical production of methyl methacrylate using high-performance hydroxyapatite-supported metal catalyst systems.
