Five-membered Cyclic Carbonates Research Articles

Non-isocyanate polyurethanes: from chemistry to applications

Conventional polyurethanes involve the use of isocyanates, which require hazardous and toxic phosgene for their manufacture. These monomers cannot be manufactured without elaborate safety devices and huge investment. Isocyanates are also considerably toxic and moisture sensitive. Growing global awareness of the need to protect our environment and continually strive to ensure the safety, health and well-being of those in the industry and consumers has created a demand for environment-friendly products. The cyclic carbonate–primary amine addition reaction which results in hydroxyurethanes is a unique reaction and has been extensively studied over the last few years. This chemistry is now attracting research interest due to its potential application in the preparation of “green”, non-porous, moisture-insensitive, isocyanate free polyurethanes. This review focuses on catalysis, the mechanism involved in the formation of Non-Isocyanate Polyurethanes (NIPU) from five-membered cyclic carbonates and the reaction kinetics for their synthesis. The higher homologues of the cyclic carbonate family, the six-membered cyclic carbonates, are similar to, but more reactive than, the five-membered cyclic carbonates and can also serve as a source for production of isocyanate free polyurethanes. This review also summarizes various application of NIPU in coatings, composites, construction and biochemical fields.

Synthesis of polycarbosilanes having a five-membered cyclic carbonate structure and their application to prepare gel polymer electrolytes for lithium ion batteries

A silacyclobutane having a five-membered cyclic carbonate structure (SBMC) was prepared, and its transition metal-catalyzed ring-opening polymerization at the four-membered carbosilane unit was investigated as well as formation of carbosilane networked polymers and polymer gel electrolytes. The SBMC was synthesized by epoxidation of 1-(4-butenyl)-1-methylsilacyclobutane followed by insertion of CO2 to the epoxide. Ring-opening polymerization of the silacyclobutane moiety in the SBMC readily proceeded by a transition metal catalyst such as platinum divinyltetramethyldisiloxane complex. A flexible networked polymer film was obtained by copolymerization of the SBMC with a small amount of crosslinker, hexamethylene-1,6-bis(1-methylsilacyclobutane) (HMBS). The copolymerization of SBMC and HMBS in 1 M LiPF6 solution in ethylene carbonate and diethyl carbonate (3/7 v/v) gave a gel polymer electrolyte, which showed good ionic conductivity and could be applied to lithium ion batteries. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Intramolecular etherification of five-membered cyclic carbonates bearing hydroxyalkyl groups

We report a new one-pot synthetic route to tetrahydrofuran derivatives, which were unexpectedly produced under basic conditions by intramolecular etherification of substituted five-membered cyclic carbonates. For alcohols with vicinal hydroxyl groups, and additional OH groups at the β-position, intramolecular etherification leading to 3-hydroxytetrahydrofuran derivatives was observed. These reactions were studied for compounds having from 2 to 6 hydroxyl groups per molecule, and the mechanism was proposed. The developed method provides a new environmentally friendly approach to the synthesis of five-membered cyclic ether derivatives under non-acidic conditions.

Water-soluble hyperbranched poly(ester urethane)s based on d,l-alanine: isocyanate-free synthesis, post-functionalization and application

The green synthesis of a novel hyperbranched poly(ester urethane) (HBPEU) has been reported via an isocyanate-free method based on D,L-alanine and a lower-toxic cyclic carbonate monomer, glycerol carbonate. Benefiting from the efficient reaction between the amine and five-membered cyclic carbonate, an AB2-type monomer bearing urethane linkages has been quantitatively formed without using a toxic isocyanate species. Subsequent bulk polyesterification was carried out to give water-soluble HBPEUs with moderate molecular weights and a degree of branching (DB) in the range of 0.44–0.52. Furthermore, the polycaprolactone arms were grafted to the HBPEU core via ring-opening polymerization of e-caprolactone initiated by the peripheral hydroxyl groups around HBPEU, forming biodegradable and biocompatible amphiphilic star copolymers, which acts as an “unimolecular reverse micelle” in CHCl3. Two water soluble dyes, methyl orange and bromophenol blue, were successfully transported from water to the insoluble chloroform phase by the core–shell star polymers, indicating the great potential of the micelles as nanocarriers. The arm lengths and core sizes of the star polymers greatly influenced the dye-loading capacity of the nanocarrier.

Chitosan functionalized ionic liquid as a recyclable biopolymer-supported catalyst for cycloaddition of CO2

Development of efficient, cheap and recyclable catalysts for a reaction under green reaction conditions is still a very attractive topic. In this work, the cycloaddition reactions of CO2 with various epoxides to form five-membered cyclic carbonates catalyzed by chitosan functionalized 1-ethyl-3-methyl imidazolium halides (CS-EMImX, X = Cl, Br) without additional solvent and metal co-catalyst were achieved in high yield and selectivity. The catalyst could be easily recovered and reused five times with high catalytic activity and selectivity. Besides, a possible catalytic cycle for the hydrogen bond assisted ring-opening of epoxide and activation of CO2 induced by the nucleophilic tertiary nitrogen of the chitosan was also proposed. The process represents a simple, ecologically safe and cost-effective route to synthesize cyclic carbonates with high product yield, as well as easy catalyst recycling.

Branched cationic polyurethane prepared by polyaddition of chloromethylated five‐membered cyclic carbonate and diethylenetriamine in molten salts

AbstractA branched cationic polymer was synthesized by polyaddition of 4‐chloromethyl‐1,3‐dioxolan‐2‐one and diethylenetriamine in molten salts. The polyaddition proceeded through nucleophilic addition of the primary amino group to the cyclic carbonate structure and quarternization of the secondary amino group with the chloromethyl group. The resulting cationic polymer was a good and recyclable catalyst for the reaction of carbon dioxide and epoxides owing to the ammonium structure. The complexation with DNA was confirmed by dynamic light scattering and zeta potential measurements, and it suggests the potential application as a carrier for drug delivery system. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Highly efficient synthesis of cyclic carbonates from CO2 and epoxides catalyzed by KI/lecithin

Development of efficient, cheap and non-toxic catalysts for the cycloaddition of CO2 with epoxides to produce five-membered cyclic carbonates is a very attractive topic. In this work, cycloaddition of CO2 with propylene oxide (PO) to propylene carbonate (PC) catalyzed by potassium halides (KCl, KBr, and KI) in the presence of lecithin, which is renewable, non-toxic, environmentally benign and biocompatible, was studied. It was discovered that potassium halides and lecithin had excellent synergetic effect in promoting the reaction, and KI/lecithin catalytic system was the most efficient among them. The effects of temperature, pressure, reaction time, and amount of catalysts on the reaction were investigated using KI/lecithin as the catalyst, and the reaction conditions were optimized. At the optimal conditions, the KI/lecithin catalytic system was also very active and selective for the cycloaddition of CO2 with other epoxides, such as glycidyl phenyl ether, epichlorohydrin, styrene oxide, 1,2-epoxyhexane, and glycidyl methacrylate. The mechanism for the synergetic effect was also studied.

A Computational Study on the Chemical Fixation of Carbon Dioxide with Epoxide Catalyzed by LiBr Salt

The chemical fixation of carbon dioxide with 2,3-epoxypropyl phenyl ether catalyzed by LiBr salt to produce a five-membered cyclic carbonate, 4-(phenoxymethyl)-1,3-dioxolan-2-one, has been extensively investigated at the B3LYP density functional level of theory. The solvent effects have been studied by means of a PCM model. All possible pathways are examined, and their corresponding energetics are demonstrated. Our results reveal that the overall reaction comprises three main steps: epoxide ring-opening, carbon dioxide insertion, and ring-closure of cyclic carbonate, none of which contains significantly large barriers. On the basis of the computed free energies of activation, the rate-determining step can be the ring-opening of epoxide or the ring-closure of cyclic carbonate with variation in the reaction conditions in N-methylpyrrolidinone (NMP) solvent. Our calculations indicate that path 2 is more favorable than path 1 in the gas phase, while both of them exist possibly in NMP solvent. The overall reaction is exothermic. Furthermore, the free energy profiles of all reaction pathways along the minima energy path in the gas phase and in NMP solvent were obtained and compared. It is shown that NMP solvent does not change the general trends for the reaction potential energy surfaces.

Chemical absorption of carbon dioxide into oxirane solution containing ID-CP-MS41 catalyst

CP-MS41 was synthesized by hydrolysis of tetraorthosilicate, as a silicon source, with 3-chloropropyltriethoxysilane as an organosilane using cetyltrimethylammonium bromide as a template. ID-CP-MS41 was synthesized by immobilization of imidazole on the CP-MS41 and was dispersed in organic liquid as a mesoporous catalyst for the reaction between carbon dioxide and oxirane. Phenyl glycidyl ether and glycidyl methacrylate were used as oxiranes. Carbon dioxide was absorbed into the oxirane solution in a stirred batch tank with a planar gas-liquid interface within a range of 0–2.0 kmol/m3 of oxirane and 333–363 K at 101.3 kPa. The measured values of absorption rate were analyzed to obtain the reaction kinetics using the mass transfer mechanism associated with the chemical reactions based on the film theory. The overall reaction of CO2 with oxirane, which is assumed to consist of two steps-i) a reversible reaction between oxirane (B) and catalyst of ID-CP-MS41 (QX) to form an intermediate complex (C1), and ii) irreversible reaction between C1 and CO2 to form QX and five-membered cyclic carbonate (C)-was used to obtain the reaction kinetics through the pseudo-first-order reaction model. Polar solvents such as N, N-dimethylacetamide, Nmethyl-2-pyrrolidinone, and dimethyl sulfoxide affected the reaction rate constants.

Synthesis of 1′,3′-Dioxolan-2′-one by the Reaction of Steroidal Oxiranes with Carbon Dioxide: Synthesis of Five-Membered Cis Cyclic Carbonates

The reaction of 3β-acetoxy-5,6α-epoxy-5α-cholestane 1, its 3β-chloro analogue 2, and 5,6α-epoxy-5α-cholestane 3 with carbon dioxide gas in the presence of sodium bromide as catalyst with continuous stirring at 100 °C for 30 min affords selectively the corresponding 1′,3′,-dioxolan-2′-ones (steroidal cyclic cis-carbonates) 4–6 in excellent yields. The structures of these products have been established on the basis of their elemental analysis and spectral data (infrared, 1H NMR, and mass).

ChemInform Abstract: Reaction of Various Oxiranes and Carbon Dioxide. Synthesis and Aminolysis of Five-Membered Cyclic Carbonates.

Various oxiranes reacted with carbon dioxide at 100 °C using lithium bromide as a catalyst under atmospheric pressure to afford the corresponding five-membered cyclic carbonates quantitatively. The rate of the reaction increased as the bulkiness of substituents on the oxirane ring was reduced or an electron-withdrawing group was introduced on the oxirane ring. The stereochemistry of the reaction of oxirane and carbon dioxide was retention without loss of optical purity. When substituted phenylethylene carbonates were reacted with benzylamine, the selectivity to afford secondary alcohol increased as the electron-withdrawing ability of the para-substituent increased.

A DFT Study on the Mechanism of the Coupling Reaction between Chloromethyloxirane and Carbon Dioxide Catalyzed by Re(CO)5Br

The detailed mechanism of the experimentally observed formation of five-membered cyclic carbonates in the coupling reaction between chloromethyloxirane and CO2 catalyzed by the Re(CO)5Br complex is revealed by means of density functional theory (DFT) calculations. All possible pathways are examined, and their corresponding energetics are demonstrated. Our calculations indicate that the real active catalyst is the unsaturated complex Re(CO)4Br rather than free radical species (Re(CO)5 or Br radicals). The preferred mechanism (path I) for the catalytic production of cyclic carbonates can be divided into three main stages involving epoxide oxidative addition, carbon dioxide insertion, and reductive elimination of cyclic carbonate, none of which contains significantly large barriers. Our results provide support for Jiang’s proposal that the reaction proceeds through the reactive oxametallacyclobutane 2b. Furthermore, we have found CO dissociation from 2b is an essential step, which facilitates CO2 coordinatio...

Preparation and Characterization of Polyhydroxyurethane/Attapulgite Nanocomposites Via In-Situ Surface-Initiated Polymerization

The polyhydroxyurethane/attapulgite nanocomposites (PHU/ATP) were prepared by in-situ surface-initiated polymerization of a five-membered cyclic carbonate, 2, 2-bis [p-(1, 3-dioxolan-2-one-4-yl-methoxy) phenyl] propane (B5CC) and hexamethylene diamine, from the surface of the aminopropyl attapulgite nanoparticles (APATP) for the first time. The chemical grafting of the polymer on the surface of ATP was confirmed by FTIR and the morphology of the attapulgite nanoparticles in the nanocomposites was examined by TEM. The thermal stabilities of the polyhydroxyurethane (PHU) and the polyhydroxyurethane/attapulgite nanocomposites (PHU/ATP) were compared with thermogravimetric analysis (TGA).The %G of the attapulgite nanoparticles was also calculated from the results of TGA after the free polyhydroxyurethane was washed off.

Reaction Kinetics of Carbon Dioxide with Phenyl Glycidyl Ether by TEA-CP-MS41 Catalyst

CP-MS41 was synthesized by hydrolysis of tetraorthosilicate, as a silicon source, with 3-chloropropyltriethoxysilane as an organosilane using cetyltrimethylammonium bromide as a template. TEA-CP-MS41 was synthesized by immobilization of triethylamine on the mesoporous MCM-41 and was dispersed in organic liquid as a mesoporous catalyst for the reaction between carbon dioxide and phenyl glycidyl ether (PGE). Carbon dioxide was absorbed into the PGE solution in a stirred batch tank with a planar gas-liquid interface within a range of 0-2.0 kmol/m3 of PGE and 333-363 K at 101.3 kPa. The measured values of absorption rate were analyzed to obtain the reaction kinetics using the mass transfer mechanism associated with the chemical reactions based on the film theory. The overall reaction of CO2 with phenyl glycidyl ether (PGE), which is assumed to consist of two steps: (i) A reversible reaction between PGE (B) and catalyst of TEA-CP-MS41 (QX) to form an intermediate complex (C1), and (ii) irreversible reaction between C1 and CO2 to form QX and five-membered cyclic carbonate (C), was used to obtain the reaction kinetics through the pseudo-first-order reaction model. Polar solvents such as N, N-dimethylacetamide, N-methyl-2-pyrrolidinone, and dimethyl sulfoxide affected the reaction rate constants.

Sc and Zn-catalyzed synthesis of cyclic carbonates from CO 2 and epoxides

Scandium can efficiently catalyze the solventless reaction of terminal epoxides with carbon dioxide in the presence of cetyltrimethylammonium bromide (CTAB) to give the corresponding five-membered cyclic carbonates in very high yields. Metal-exchanged montmorillonites proved to be an excellent and highly effective solution for the immobilization of Sc and Zn in this reaction.

Anionic Ring-Opening Copolymerization of L-Lactide with a Five-Membered Cyclic Carbonate Having a Glucopyranoside Structure

The anionic ring-opening copolymerization of L-lactide (LL) with a five-membered cyclic carbonate having the glucopyranoside structure, methyl 4,6-O-benzilidene-2,3-O-carbonyl-α-D-glucopyranoside (MBCG), was carried out using potassium tert-butoxide (t-BuOK) as the initiator and tetrahydrofuran (THF) as the solvent at 30°C for 12h. The mole fractions of LL in the copolymer (fLL) of all copolymers were nearly equal to the corresponding mole fraction of LL in the feed (FLL). Deprotection of the copolymer was performed using trifluoroacetic acid in dichloromethane. 1H NMR spectra of the resulting product indicated that deprotection was completely achieved due to the absence of the aromatic proton signals.

MOF-5/n-Bu4NBr: an efficient catalyst system for the synthesis of cyclic carbonates from epoxides and CO2 under mild conditions

The development of efficient heterogeneous catalysts for the cycloaddition of CO2 with epoxides to produce five-membered cyclic carbonates under mild reaction conditions is of great importance. In this work, the coupling reaction of CO2 with propylene oxide (PO) to produce propylene carbonate (PC) catalyzed by MOF-5 (metal-organic frameworks) in the presence of quaternary ammonium salts (Me4NCl, Me4NBr, Et4NBr, n-Pr4NBr, n-Bu4NBr) was studied in different conditions. It was discovered that MOF-5 and quaternary ammonium salts had excellent synergetic effect in promoting the reaction, and the MOF-5/n-Bu4NBr catalytic system was the most efficient among them. The optimal temperature for the reaction was around 50 °C. The reaction could be completed in 6 h at low CO2 pressure with very high selectivity. A decrease of the yield of PC was not noticeable after MOF-5 was reused three times, indicating that the MOF-5 was stable. The MOF-5/n-Bu4NBr catalytic system was also very active and selective for the cycloaddition of CO2 with other epoxides, such as glycidyl phenyl ether, epichlorohydrin and styrene oxide. The mechanism for the coupling reaction is also discussed.

Preparation and characterization of poly(hydroxyurethane) /halloysite nanocomposites via in-situ polymerization

AbstractNaturally occurring halloysite nanotubes (HNTs) with hollow nanotubular structures were used as a new type filler for polyhydroxyurethane. The polyhydroxyurethane/halloysite nanocomposites (PHU/HNTs) were prepared by the in-situ surface-initiated polymerization of a five-membered cyclic carbonate 2,2- bis[p-(1,3-dioxolan-2-one-4-yl-methoxy) phenyl] propane (B5CC) and hexa methylene diamine, from the surfaces of the aminopropyl halloysite nanotubes (APHNTs) for the first time. The percentage of grafting (PG %) and the grafting efficiency (GE %) of 41% and 23% were calculated from the results of the thermogravimetric analysis (TGA) and from the results of elemental analysis (EA) respectively after the free polyhydroxyurethane was washed off. The chemical grafting of the polymer was also confirmed using FTIR; the morphology of the silica nanotubes in the nanocomposite was examined by transmission electron microscope (TEM).

Synthesis of cyclic carbonates from epoxides and CO2 catalyzed by potassium halide in the presence of β-cyclodextrin

Development of efficient, cheap and non-toxic catalysts for cycloaddition of CO2 with epoxides to produce five-membered cyclic carbonates under greener reaction conditions is still a very attractive topic. In this work, cycloaddition of CO2 with propylene oxide (PO) to propylene carbonate (PC) catalyzed by potassium halide (KCl, KBr, and KI) in the presence of β-cyclodextrin was studied at various conditions. It was discovered that potassium halide and β-cyclodextrin (β-CD) showed excellent synergetic effect in promoting the reactions, and KI-β-CD catalytic system was the most efficient among them. The optimal temperature for the reaction was around 120 °C, and the reaction rate reached maximum at about 6 MPa at this temperature. The reaction could be completed in 4 h with very high selectivity. The decrease of the yield of PC was not noticeable after KI-β-CD was reused five times, indicating that the catalyst was very stable. KI-β-CD catalytic system was also very active and selective for cycloaddition of CO2 with other epoxides, such as glycidyl phenyl ether, epichlorohydrin, and styrene oxide. The mechanism for the synergetic effect is discussed.

Synthesis of cyclic carbonate from carbon dioxide and diols over metal acetates

Different metallic acetates were used as the catalysts to synthesize cyclic carbonates from carbon dioxide and diols in the presence of acetonitrile. In the course of reaction, acetonitrile acted as not only the solvent but also the dehydrating reagent to eliminate the effect of the water produced from the reaction. Thus, the thermodynamic equilibrium was shifted and the yield of cyclic carbonates was improved. Using 1,2-propylene glycol as the reactant to screen the catalysts, it was found that anhydrous zinc acetate possessed the highest catalytic activity. The reaction of carbon dioxide and diols was systemically studied over anhydrous zinc acetate. The results showed that the yields of five-membered cyclic carbonates were obviously higher than that of six-membered cyclic carbonates and the yield of 1,2-propylene carbonate was the highest. Using 1,2-propylene glycol as the reactant and anhydrous zinc acetate as the catalyst, the reaction conditions were optimized as 1,2-propylene glycol 100 mmol, acetonitrile 10 mL, catalyst 2.5 mmol, reaction pressure 10 MPa, reaction temperature 170°C, and reaction time 12 h. Under the optimal conditions, the yield of 1,2-propylene carbonate was 24.2% and the conversion of 1,2-propylene glycol was 38.9%.