Reaction Of Carbonate Research Articles

Asymmetric [3+2] Cycloaddition of Olefins with Morita–Baylis–Hillman Carbonates Catalyzed by BINOL-Based Bifunctional Phosphine

We have developed a series of novel BINOL-based phosphines. These bifunctional organocatalysts can be used in the [3+2] cycloaddition of electron-deficient olefins and Morita–Baylis–Hillman (MBH) carbonates. Moderate to excellent yields (up to >99%) and good to excellent enantioselectivities (up to 95% ee) can be obtained in the cycloaddition reaction of maleimides and MBH carbonates. The application of these novel phosphines can be further extended to the asymmetric synthesis of chiral spirooxindoles (up to 85% ee). The results in this study indicate that the BINOL moiety plays an important role in stereocontrol.

Highly Selective Room‐Temperature Catalyst‐Free Reduction of Alkaline Carbonates to Methane by Metal Hydrides

The realization of effective CO2 conversion into valuable hydrocarbons is a promising way of addressing the current environmental and energy issues. A convenient, highly selective, and efficient method of CO2 methanation and the synthesis of COx‐free hydrogen/methane fuel mixtures by ball milling‐induced reactions of alkaline carbonates with metal hydrides (MHs) is reported. The natural resources of MgCO3/CaCO3 and MgH2/CaH2 are used as carbon and hydrogen sources, respectively. Mechanochemical investigations of the room‐temperature reactions indicate that some alkaline carbonates can be reduced by MHs under catalyst‐free conditions to selectively afford CH4 as the sole hydrocarbon product in yields of up to 73%. Moreover, the contents of methane in the gaseous products and its yield are shown, which mainly depend on the nature of metal carbonates/hydrides, rate and duration of ball milling, and reaction mixture composition. Thus, this study opens new ways to achieve the CO2 utilization and synthesize of COx‐free hydrogen and methane fuel mixtures.

Development of a Stimuli‐Responsive Gemini Zwitterionic Viscoelastic Surfactant for Self‐Diverting Acid

AbstractA Gemini zwitterionic viscoelastic surfactant named self diverting acid ‐ gemini sulfonated surfactant (SDA‐GS), which has double quaternary ammonium groups, double sulfonate groups, and two hydrophobic tails, was synthesized from oleylamidopropyl dimethylamine, 1,3‐propanesultone, and 2, 2‐bis(bromomethyl)propane‐1, 3‐diol. The viscosity of an SDA‐GS aqueous solution varies with acid and calcium chloride concentrations. With a decrease in the HCl concentration, the viscosity of the acid solution prepared with SDA‐GS increases to a maximum value, followed by a decrease, which results from the aggregation of the surfactant into wormlike micelles and the following disaggregation. Calcium ions generated by the reaction of acid and calcium carbonate can enhance the aggregation of the surfactant to increase the peak viscosity of the acid solution. The peak viscosity of the acid solution prepared by 5 wt.% SDA‐GS without calcium ions could only reach 73.2 mPa.s when the HCl concentration was 4 wt.%, but that of the acid solution with calcium carbonate powder added could reach over 200 mPa.s when the HCl concentration was consumed to 4 wt.% and the calcium chloride concentration 21.6 wt.%. The viscoelastic measurements proved that calcium ions can drive the growth of the wormlike micelle. The acid and Ca2+ response of SDA‐GS can be applied in self‐diverting acid to improve the acid displacement in the heterogeneous reservoir. Experimental evaluation showed that the acid solution prepared by SDA‐GS and the selected corrosion inhibitor showed a good corrosion inhibition performance and a viscosity variation that makes it an efficient self‐diverting acid. The spent acid (21.6 wt.%) with 4 wt.% HCl retained high viscosity over 80 mPa.s at a 170 s−1 shearing rate and at 120°C after 90 min. The parallel core flood tests to simulate in situ application of SDA‐GS acid showed that the permeability improvement ratios (K1/K0) of the cores could reach 182.3 and 278.4 at 60 and 90°C, respectively.

Non-isocyanate polyurethane adhesive from sucrose used for particleboard

Sucrose-based non-isocyanate polyurethanes (S-NIPU) were synthesized by the already codified reaction of sucrose, dimethyl carbonate and hexamethylene diamine and used for the first time as adhesives for bonding particleboard. To decrease the NIPU adhesive curing temperature, a silane coupling agent was used as a crosslinking promoter. The performance of particleboards prepared at a press temperature of 230 °C, 200 °C and 180 °C and a press time of 8 min, 10 min and 12 min was tested and evaluated. The structure of the oligomers obtained was detected by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Thermomechanical analysis and differential scanning calorimetry were also used to analyze their behavior. The particleboards bonded with the S-NIPU adhesive at 230 °C showed excellent properties, which, however, decreased as the press time was reduced. The silane coupling agent used as a crosslinking promoter significantly reduced the curing temperature of the adhesive and allowed to obtain good bonding at a lower press temperature. The results obtained confirmed that coupling the S-NIPU adhesive with a silane used as a crosslinking promoter can yield sufficiently improved results to function as a suitable adhesive for particleboard, medium density fiberboard and other types of particulate wood panels. It was also the first time that a NIPU adhesive was used for wood bonding.

Automated spectrophotometric determination of carbonate ion concentration in seawater using a portable syringe pump based analyzer

Observations of seawater carbonate ion concentrations are critical to assess the ecological effects of ocean acidification. Nevertheless, currently available methods are labor intensive or too complex for field applications. Here, we report the design and performance of the first fully automated portable carbonate ion analyzer. Measurements are based on reaction of carbonate and chloride ions with Pb(II) followed by quantitative UV spectrophotometric detection of the PbCO30 complex. The core hardware is a syringe pump equipped with a multi-position valve that is controlled by software written in LabVIEW. Measurement precision is 1.1% (n = 13) with a measurement frequency of 12 h−1. The analyzer was used to continuously monitor carbonate ion concentration variations in a 2500 L coral reef tank for five days (test 1), and used for shipboard underway and vertical profile analysis during a 13-day cruise (test 2). The analyzer attained a combined standard uncertainty of 3.0%, which meets the Global Ocean Acidification Observing Network's “weather level” goal. Through use of a syringe pump mechanism for mixing seawater and reagent solution, the analyzer is robust, functionally flexible, and quite suitable for continuous environmental monitoring under harsh conditions.

Enantioselective Acyl Migration Reactions of Furanyl Carbonates with Chiral DMAP Derivatives.

An efficient enantioselective acyl migration reaction of furanyl carbonates was developed to construct all-carbon quaternary stereogenic centers. In some cases, the reactions required only 0.05 mol % (minimum 500 ppm) of catalyst and showed a high turnover frequency value (TOF; 3640 h-1 ). Multigram-scale reactions (10 grams) also proceeded with high enantioselectivity (>99:1 e.r.) in quantitative yield. The catalyst was robust and easily recovered in 98 % yield. A wide range of functional groups were tolerated (15 examples, >98 % yield, up to >99:1 e.r.), and a variety of optically active 3,3'-disubstituted benzofuranone derivatives, which are useful intermediates for the synthesis of natural products and pharmaceuticals, were efficiently obtained. Control experiments on the catalyst structure (e.g., catalyst 1 a vs. 1 a' and 1 a'') and computational calculations revealed that both the catalytic activity and enantioselectivity should be enhanced by hydrogen bonding between catalyst and substrate. Moreover, this system was applied to the challenging γ-selective acyl migration reaction of furanyl carbonates with high γ-selectivity and high enantioselectivity (α:γ=10:90, 95:5 e.r.).

Enantioselective Synthesis of Chiral Medium-Sized Cyclic Compounds via Tandem Cycloaddition/Cope Rearrangement Strategy

The nine-membered ring-bearing bicyclo[5.2.2]tetrahydrooxonines frameworks have enantioselectively been constructed via a tandem [3 + 2] cycloaddition/Cope rearrangement reaction of vinylethylene carbonates (VECs) with coumalates or pyrones. Under mild conditions, palladium-catalyzed asymmetric tandem reaction of various substituted VECs and coumalates or pyrones proceeds smoothly to produce the corresponding medium-sized heterocyclic compounds in high yields with very high enantioselectivities. Moreover, the reaction on the gram scale and further diverse transformations of the products were workable. The reaction mechanism was investigated through control experiments and DFT calculations, which show the reaction proceeds via a tandem [3 + 2] cycloaddition/Cope rearrangement pathway rather than via a [5 + 4] cycloaddition pathway.

Promising approaches to improve the performances of hybrid non‐isocyanate polyurethane

AbstractThe performances of hybrid non‐isocyanate polyurethane (NIPU) materials were improved by using promising approaches. For the ring‐opening reaction of cyclic carbonate with excess amine, methanol was selected as solvent to increase the molar mass of NH2‐terminated NIPU pre‐polymer but also caused the formation of urea as a result of eliminating hydrogen bonding between NIPU chains. Meanwhile, another approach was carried out to reduce the content of urea by altering the introduction mode of reactants, along with further increasing the molar mass of the NIPU pre‐polymer. The final hybrid materials were prepared by adding bisphenol‐A diglycidyl ether into the pre‐polymer. The results indicated that the introduction of methanol and the change of the introduction mode of reactants could improve the performance of the hybrid materials. The hybrid material derived from the forward method has optimal performance with a tensile strength of 10.8 MPa, elongation at break of 167%, a glass transition temperature of 49.1 °C and a crosslinking density of 450 mol m−3 as well as presentable thermodynamic stability, ascribed to the high molar mass of the NIPU pre‐polymer, the low urea content and the dense crosslinking network. © 2018 Society of Chemical Industry

An innovative synthesis pathway to benzodioxanes: the peculiar reactivity of glycerol carbonate and catechol

A peculiar reactivity of glycerol carbonate (GlyC) as an innovative and highly reactive alkylating agent for phenolic compounds is investigated in this article.

Catenated and spirocyclic polychalcogenides from potassium carbonate and elemental chalcogens.

The reaction of potassium carbonate with elemental sulfur or selenium in acetone in the presence of [PPN]Cl (PPN = (Ph3P)2N) produces catena-[S12]2-, the longest structurally characterised polysulfide dianion, or spiro-[Se11]2- as ion-separated [PPN]+ salts.

Efficient synthesis of tetrasubstituted 2,3-allenoates and preliminary studies on bioactivities

A general and highly efficient straightforward protocol for the preparation of tetrasubstituted 2,3-allenoates through a palladium-catalyzed coupling reaction of 3-alkoxycarbonyl propargylic carbonates and boronic acids with commercially available tri(o-tolyl)phosphine as a ligand has been developed.

Synthesis of 2-Aryloxy-1,3-dienes from Phenols and Propargyl Carbonates.

A convenient method for the synthesis of 1,3-dienes from readily available compounds is reported. 2-Aryoxy-1,3-dienes are produced stereoselectively by a nickel-catalyzed reaction of propargyl carbonates with phenols. Functional group tolerance is broad to allow iodo, formyl, and boryl groups. The resulting 1,3-dienes are of much synthetic value because they can participate in a wide variety of reactions, including the Diels-Alder reaction.

Iridium‐Catalyzed Propenylation Reactions for the Synthesis of 4‐Pyridone Derivatives

AbstractHerein we report an iridium‐catalyzed propenylation reaction of allylic carbonates with 4‐hydroxypyridine derivatives. The process efficiently provides 4‐pyridone derivatives with high stereoselectivities under mild conditions. The products could constitute valuable building blocks for the synthesis of natural products and other bioactive molecules. Preliminary mechanistic studies indicated that a tandem allylic substitution/isomerization reaction occurs to afford the propenylation products.magnified image

Enantioselective [3 + 2] Cycloaddition Reaction of Ethynylethylene Carbonates with Malononitrile Enabled by Organo/Metal Cooperative Catalysis.

The first catalytic asymmetric decarboxylative [3 + 2] cycloaddition reaction of ethynylethylene carbonates with malononitrile has been developed successfully by an organo/copper cooperative system. This strategy led to a series of optically active polysubstituted dihydrofurans in good yields with high levels of enantioselectivities (up to 99% yield, 97% ee). The presence of the terminal alkynyl and the cyano group in the dihydrofuran products provides a wide scope for further structural transformations. More importantly, this organo/metal cooperative catalytic system will broaden the substrate scope and enable fundamentally new reactions.

SOLUBILITY IN ALCOHOLS AND ALCOHOLYSIS REACTIONS OF CARBONATES, SULFIDES, CYANIDES, AND PHOSPHATES OF ALKALI METALS

The published data on the solubilities of lithium, sodium, potassium, rubidium and cesium carbonates; sodium bicarbonate; sodium sulphide; potassium and sodium cyanides; orthophosphates, hydro- and dihydroorthophosphates of potassium and sodium, as well as sodium pyrophosphate in methanol, ethanol, 2-propanol, 2-methyl-1-propanol, benzyl alcohol, ethylene glycol, methyl cellosolve and glycerol have been considered and collected. A little bit information for salts has been taken from the most common solubility handbooks, but most of data was selected from scientific articles. There is an acid-base equilibrium with the formation of the corresponding alcoholates in the systems "potassium or sodium carbonate/methanol, ethanol, ethylene glycol, ethylene glycol monomethyl ether", "sodium sulphide/methanol, ethanol, 2-propanol, 2-methyl-1-pro-panol, benzyl alcohol", "potassium cyanide/methanol, ethylene glycol, glycerol", "potassium or sodium orthophosphate/ethylene glycol", and "sodium pyrophosphate/ethylene glycol". The mechanism of the reaction of alcoholysis and the formation of alcoholates from the alkali metal salts and alcohols is based on the distribution of the components in phases. Analysis of all phases in the alcohol solutions of alkali metal salts proved the presence of an alcoholysis reaction in some salt/alcohol systems. The concentrations of dissolved salts in alcoholate-generating systems are significantly lower than those determined by the gravimetric method without taking into account the alcoholysis reaction and are considered in the common handbooks "solubilities of the corresponding salts in alcohols". A classification of inorganic alkali metal salts reacting with alcohols in the alcoholysis reaction has been proposed. The analysis of literature data showed that along hydroxides and alkali metal salts, the hydrides, organometallic compounds, acetylenides, nitrides, amides (including alkyl amides) as well as azides can react with alcohols to form alkoxides by alcoholysis reaction. Alcoholysis of salts can be considered as a promising method for the production of alkali metal alkoxides in which the salt is used instead of metal or hydroxide.

Iridium/N-Heterocyclic Carbene Complex-Catalyzed Intermolecular Allylic Alkylation Reaction

N-Heterocyclic carbenes (NHCs) were found to be suitable ligands in Ir-catalyzed intermolecular allylic alkylation reaction. In the presence of a catalyst derived from [Ir(dncot)Cl]2 (dncot = dinaphthocyclooctatetraene) and triazolium salt L7, the alkylation products from the reaction of aryl allyl carbonates with sodium dialkyl malonates could be obtained in 85–99% yields favoring the formation of branched products (90/10 → >99/1 b/l). In addition, chiral dihydroisoquinoline-type NHC (DHIQ-NHC) (L8) is successfully applied in Ir-catalyzed asymmetric allylic alkylation reactions. Excellent enantioselectivities and moderate regioselectivities were obtained for a wide range of substrates.

A new industrial process of NaHCO3 and its crystallization kinetics by using the common ion effect of Na2CO3

Sodium bicarbonate (NaHCO3) has been conventionally manufactured by a carbonation synthesis from the reaction of sodium carbonate (Na2CO3) and CO2 in a carbonation column. To enhance the quality and the production yield of NaHCO3, it is imperative to carefully control supersaturation in the carbonation crystallization process and make NaHCO3 concentration of filtrate obtained from column bottom possibly least. A new method of NaHCO3 production was proposed with help of common ion effect by adding Na2CO3 as feed in filtering liquor. A cooling crystallizer was incorporated in the system after the carbonation tower to generate more NaHCO3. The crystallization kinetics of NaHCO3 including nucleation and crystal growth was experimentally and theoretically investigated in a continuous mixed-suspension-mixed-product removal (MSMPR) crystallizer cooled from 353 to 308 K. The effect of Na2CO3 concentration and additives on the crystallization of NaHCO3 was studied. The growth and nucleation rate GV=6.618×10-15σ0.290, B0=2.560×10-32GV-3.82MT1.11 were determined by moments analysis based on the experimental crystal size distribution (CSD) data. The kinetic parameters in two empirical equations were estimated by linear regression with the 0.290 of the relative supersaturation rate order, indicating that the meant surface integration and diffusion play an equally importance to the growth of NaHCO3 crystal. The growth rate order of −3.82 suggested that nucleation of NaHCO3 from the Na2CO3-rich solution in the MSMPR crystallizer was particle size-limiting.

Mechanism and kinetics of the oxidation of dimethyl carbonate by hydroxyl radical in the atmosphere.

The mechanism and kinetics for the reaction of dimethyl carbonate (DMC) with OH radical have been studied by using quantum chemical methods. Four reaction pathways were identified for the initial reaction. In the first two pathways, hydrogen atom abstraction is taking place and alkyl radical intermediate is formed with the energy barrier of 6.4 and 7.9kcal/mol. In the third pathway, OH addition reaction to the carbonyl carbon (C2) atom of DMC and intermediate, I2, is formed with an energy barrier of 11.9kcal/mol. In the fourth pathway, along with CH3O●, methyl hydrogen carbonate is formed. For this C-O bond breaking and O-H addition reaction, the energy barrier is 27kcal/mol. The calculated enthalpy and Gibbs energy values show that the studied initial reactions are exothermic and exoergic except the OH addition reaction. For the initial reactions, the rate constants were calculated by using canonical variational transition state theory (CVT) with small curvature tunneling (SCT) correction over the temperature range of 278-1200K. At 298K, the calculated rate coefficient for the in-plane and out-of-plane hydrogen atom abstraction reaction pathway is 2.30 × 10-13 and 0.02 × 10-13cm3molecule-1s-1. Further, the reaction between alkyl radical intermediate formed from the first pathway and O2 is studied. The reaction of alkyl peroxy radical intermediate with atmospheric oxidants, HO2, NO, and NO2 is also studied. It was found that the formic (methyl carbonic) anhydride is the end product formed from the atmospheric oxidation and secondary reactions of DMC.

Carbon Isotope Composition of Diamond Crystals Grown Via Redox Mechanism

We report the carbon isotope compositions of a set of diamond crystals recovered from an investigation of the experimental interaction of metal iron with Mg–Ca carbonate at high temperature and high pressure. Despite using single carbon source with δ13C equal to +0.2‰ VPDB, the diamond crystals show a range of δ13C values from –0.5 to –17.1‰ VPDB. Diamonds grown in the metal-rich part of the system are relatively constant in their carbon isotope compositions (from –0.5 to –6.2‰), whereas those diamonds recovered from the carbonate dominated part of the capsule show a much wider range of δ13C (from –0.5 to –17.1‰). The experimentally observed distribution of diamond’ δ13C using a single carbon source with carbon isotope ratio of marine carbonate is similar to that found in certain classes of natural diamonds. Our data indicate that the δ13C distribution in diamonds that resulted from a redox reaction of marine carbonate with reduced mantle material is hardly distinguishable from the δ13C distribution of mantle diamonds.

Intrinsic reaction kinetics and mechanism for the reverse disproportionation reaction to methyl phenyl carbonate

The extensive researches about the thermodynamic and intrinsic kinetic of disproportionation reaction of methyl phenyl carbonate to diphenyl carbonate were investigated independently with dibutyltin oxide as a catalyst, at a temperature range of 433.15–473.15 K and different catalyst concentrations in a stirred batch reactor, for a deeper knowledge of reaction essence. This reaction was found endothermic and showed hardly any reaction in the absence of catalyst which indicate an inferior kinetic characteristics. The reaction rate increases with an increasing catalyst concentration until the concentration went to 8.08 × 10−4 mol mol−1. A possible mechanism involving an in-situ Sn-based species was proposed and finally verified by a good agreement between experimental and simulated data. The available Sn-based species was then demonstrated to play a real catalytic role by extra experiments. All results can also be further utilized to explore the essence of transesterification reaction network.