Six-membered Cyclic Carbonate Research Articles

Organocatalysts for the Controlled “Immortal” Ring‐Opening Polymerization of Six‐Membered‐Ring Cyclic Carbonates: A Metal‐Free, Green Process

Six-membered cyclic carbonates, namely trimethylene carbonate (TMC), 3,3-dimethoxytrimethylene carbonate (DMTMC) and 3-benzyloxytrimethylene carbonate (BTMC), undergo controlled "immortal" ring-opening polymerization (iROP) under mild conditions (bulk, 60-150 °C), by using organocatalysts, including an amine [4-N,N-dimethylaminopyridine (DMAP)], a guanidine [1,5,7-triazabicyclo-[4.4.0]dec-5-ene (TBD)], or a phosphazene [2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine (BEMP)], in the presence of an alcohol [benzyl alcohol (BnOH), 1,3-propanediol (PPD), glycerol (GLY)] that acts as both a co-initiator and a chain-transfer agent. Remarkably, such organocatalysts remain highly active in the iROP of technical-grade, unpurified TMC. Under optimized conditions, as much as 100,000 equivalents of TMC were fully converted by as little as 10 ppm of BEMP with the simultaneous growth of as many as 200 polymer chains, allowing the preparation of high molar mass poly(trimethylene carbonate)s (up to 45,800 g mol(-1)). These catalyst systems enable among the highest activities (TOF=55,800 h(-1)) and productivities (TON=95,000) ever reported for the ROP of TMC.

A facile catalytic synthesis of trimethylene carbonate from trimethylene oxide and carbon dioxide

The coupling of oxetane (trimethylene oxide) and carbon dioxide catalyzed by VO(acac)2 in the presence of an onium salt was studied. The process was found to be highly selective and quantitative for the production of the six-membered cyclic carbonate, trimethylene carbonate, under very mild reaction conditions of 60 °C and 1.7 MPa. Other derivatives of trimethylene oxide were shown to similarly selectively afford the corresponding cyclic carbonates upon reaction with CO2.

Conformational analysis of six-membered cyclic carbonates

The conformational isomerization of 2-oxo-1,3-dioxane and its methyl analogs was investigated by means of ab initio RHF//6-31G(d,p) and MP2//6-31G(d,p) quantum-chemical methods. It is shown that in comparison with 1,3-dioxanes the potential energy surface of the mentioned compounds has a fewer number of stationary points and includes two minima corresponding to conformers of sofa or distorted sofa configuration and one maximum corresponding to 2,5-twist form. The value of potential barrier of interconversion of cyclic carbonates is significantly lower than that of the analogously substituted 1,3-dioxanes.

Synthesis, characterization and ring-opening polymerization of a novel six-membered cyclic carbonate bearing pendent allyl ether group

A novel six-membered cyclic carbonate with pendent allyl ether group, 5-allyloxy-1,3-dioxan-2-one (ATMC), was synthesized from glycerol, and the corresponding polycarbonate, poly(5-allyloxy-1,3-dioxan-2-one) (PATMC) was further synthesized by ring-opening polymerization in bulk at 120°C. Two kinds of catalyst, tin(II) 2-ethylhexanoate (Sn(Oct)2) and immobilized porcine pancreas lipase on silica particles (IPPL), were employed to perform the polymerization. The structures of the novel monomer and the resulting functional polymers were confirmed by FTIR, 1H NMR, 13C NMR, GPC and DSC. The molecular weight (Mn) of PATMC decreased rapidly with the increase of IPPL or Sn(Oct)2 concentration. The highest molecular weight (Mn=48,700g/mol) of PATMC with the polydispersity of 1.31 was obtained at 0.1wt% concentration of IPPL for 48h. Postpolymerization oxidation reactions to epoxidize the unsaturated bonds of the PATMC were also achieved. The epoxide-containing polymers could afford facilities for further modification.

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%.

Synthesis of cyclic carbonates from urea and diols over metal oxides

Several metal oxides were used for synthesis of ethylene carbonate from urea and ethylene glycol. ZnO showed high activity towards the reaction. TPD, FTIR and reaction test indicated that the catalysts with appropriate acid and base properties were favorable to the synthesis of cyclic carbonate. Furthermore, the reaction of urea with various diols revealed that the selectivity of five-membered cyclic carbonates was higher than that of six-membered cyclic carbonates.

Ring‐opening metathesis copolymerization behaviors of cyclooctene and norbornene bearing a five‐ or six‐membered ring cyclic carbonate

Ring-opening metathesis copolymerizations (co-ROMPs) of norbornene derivatives bearing five- or six-membered ring cyclic carbonate and cyclooctene were carried out with a ruthenium catalyst under various polymerization conditions. All co-ROMPs smoothly gave the corresponding copolymers in good yields, and the lass-transition temperatures of the resulting polymers and the degrees of volume change during the copolymerizations were simultaneously controlled by the amount of the comonomer.

Synthesis and Chemical Recycling of a Polycarbonate Obtained by Anionic Ring-Opening Polymerization of a Bifunctional Cyclic Carbonate

This article deals with anionic ring-opening polymerization of a bifunctional cyclic carbonate consisting of both five- and six-membered rings (65CCP) and anionic depolymerization of the obtained polymer. Anionic ring-opening polymerization of 65CCP initiated with 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) afforded a polycarbonate remaining a five-membered cyclic carbonate group in the side chain (P(65CCP)) by the selective polymerization of the six-membered cyclic carbonate ring. The equilibrium nature of the polymerization allowed the efficient depolymerization of P(65CCP) by a catalytic amount of DBU to recover 65CCP in high yield, in which the five-membered cyclic carbonate ring also remained unreacted.

Six-Membered Cyclic Carbonate Having Styrene Moiety as a Chemically Recyclable Monomer. Construction of Novel Cross-Linking−De-Cross-Linking System of Network Polymers

This article deals with (1) synthesis and anionic polymerization of a six-membered cyclic carbonate having styrene moiety, (2) anionic depolymerization of the obtained polymer, (3) radical cross-linking of the obtained polymer, and (4) anionic de-cross-linking of the cross-linked polymer. The monomer 5-ethyl-5-[(p-vinylphenyl) methoxymethyl]-1,3-dioxan-2-one (St6CC) underwent anionic polymerization with potassium tert-butoxide (t-BuOK) as an initiator in THF to afford the corresponding polycarbonate [poly(St6CC)]. It was confirmed that this polymerization was equilibrium polymerization by the relationships between the polymerization temperature and monomer conversion. Poly(St6CC) underwent anionic depolymerization with t-BuOK (5 mol % vs polymer repeating unit) as a catalyst in THF (0.1 M) at 20 °C for 24 h to recover St6CC in 60% yield. Treatment of poly(St6CC) with a radical initiator afforded the cross-linked polymer. Employment of styrene as the comonomer satisfactorily afforded the corresponding cros...

Coordination chemistry of ester-functionalized cp ligands: synthesis and catalytic activity of [Rh{CpCO 2(CHPh) 2OH}(NBD)] and [Rh{CpCO 2(CH 2) 3OH}(NBD)

Two new sodium hydroxyalkoxycarbonylcyclopentadienide salts Na[ rac-CpCO 2(CHPh) 2OH] ( 1) and Na[( 2S,3S)-CpCO 2(CHPh) 2OH] ( 2) were prepared by reaction of NaCp with the five-membered cyclic carbonates cis-4,5-diphenyl-1,3-dioxolan-2-one and (4 S,5 S)-4,5-diphenyl-1,3-dioxolan-2-one. The reaction of these salts with [Rh(NBD)Cl] 2 gave [Rh{ rac-CpCO 2(CHPh) 2OH}(NBD)] ( 3) and (−)-[Rh{(2 S,3 S)-CpCO 2(CHPh) 2OH}(NBD)] ( 4) whose catalytic activity in the hydroformylation of hex-1-ene and styrene has been investigated and compared with that of the previously reported rhodium complexes [Rh{CpCO 2(CHR) 2OH}(NBD)] (R=H, Me). In addition we also discuss some preliminary results regarding the behavior of these complexes in the hydrogenation of the same substrates. The reactivity of NaCp toward the six-membered cyclic carbonate 1,3-dioxan-2-one has also been studied and it has been found that the reaction leads to two cyclopentadienide anions [CpCO 2(CH 2) 3OH] − ( 5) and [CpCO 2(CH 2) 3OC(O)O(CH 2) 3OH] − ( 6) in amounts strictly dependent on the carbonate/NaCp stoichiometric ratio.

Novel biodegradable aliphatic poly(butylene succinate-co-cyclic carbonate)s with functional carbonate building blocks. 1. Chemical synthesis and their structural and physical characterization.

This study presents chemical synthesis, structural, and physical characterization of novel biodegradable aliphatic poly(butylene succinate-co-cyclic carbonate)s P(BS-co-CC) bearing functional carbonate building blocks. First, five kinds of six-membered cyclic carbonate monomers, namely, trimethylene carbonate (TMC), 1-methyl-1,3-trimethylene carbonate (MTMC), 2,2-dimethyl-1,3-trimethylene carbonate (DMTMC), 5-benzyloxytrimethylene carbonate (BTMC), and 5-ethyl-5-benzyloxymethyl trimethylene carbonate (EBTMC), were well prepared from ethyl chloroformate and corresponding diols at 0 degrees C in THF solution with our modified synthetic strategies. Then, a series of new P(BS-co-CC)s were synthesized at 210 degrees C through a simple combination of poly-condensation and ring-opening-polymerization (ROP) of hydroxyl capped PBS macromers and the prepared carbonate monomers, and titanium tetra-isopropoxide Ti(i-OPr)4 was used as a more suitable catalyst of 5 candidate catalysts which could concurrently catalyze poly-condensation and ROP. By means of NMR, GPC, FTIR, and thermal analytical instruments, macromolecular structures and physical properties have been characterized for these aliphatic poly(ester carbonate)s. The experimental results indicated that novel biodegradable P(BS-co-CC)s were successfully synthesized with number average molecular weight Mn ranging from 24.3 to 99.6 KDa and various CC molar contents without any detectable decarboxylation and that the more bulky side group was attached to a cyclic carbonate monomer, the lower reactivity for its copolymerization would be observed. The occurrences of 13C NMR signal splitting of succinyl carbonyl attributed to the BS building blocks could be proposed due to the randomized sequences of BS and CC building blocks. FTIR characterization indicated two distinct absorption bands at 1716 and 1733 approximately 1735 cm(-1), respectively, stemming from carbonyl stretching modes for corresponding BS and CC units. With regard to their thermal properties, it is seen that the synthesized P(BS-co-CC)s exhibited thermal degradation temperatures 10 approximately 20 degrees C higher than that of PBS. On the basis of the synthesized P(BS-co-BTMC)s, new aliphatic poly(butylene succinate-co-5-hydroxy trimethylene carbonate)s were further synthesized, bearing hydrophilic hydroxyl pendant functional groups through an optimized Pd/C catalyzed hydrogenation. These semi-crystalline new biodegradable aliphatic copolymers with tunable physical properties and functional carbonate building blocks might be expected as potential new biomaterials.

Macrocyclic vs. Linear Polymer Formation in the Coordination- Insertion Polymerization of Cyclic Carbonates

Investigations on the mechanistic aspects of the coordination-insertion polymerization of six-membered cyclic carbonate 5,5-dimethyl-1,3-dioxan-2-one (DTC) initiated by tin(II) alkoxide-based catalysts are presented. 1 H NMR and MALDI-TOF mass spectrometric analyses of the DTC polymerization products revealed that predominantly macrocyclic oligocarbonates are formed in the presence of a stannane catalyst. It was found that the addition of a small amount of water or diol suppresses the macrocyclization and linear polycarbonates can be obtained. The plausible mechanism of macrocyclization and linear product formation is proposed and discussed.

Self-Polyaddition of Six-Membered Cyclic Carbonate Having Fmoc-Protected Amino Group: Novel Synthetic Method of Polyhydroxyurethane

This article deals with the self-polyaddition of 3-(1,3-dioxan-2-one-5-yl)propyl 2-(9-fluorenylmethoxycarbonylamino)ethyl thioether by the deprotection of the 9-fluorenylmethyoxycarbonyl (Fmoc) group with N,N-diisopropylethylamine, 4-(dimethylamino)pyridine, or triethylamine as a novel synthetic method of a polyhydroxyurethane. The polymer with higher yields and Mn's was obtained by using N,N-diisopropylethylamine and 4-(dimethylamino)pyridine than triethylamine. Fmoc deprotection and stability of the cyclic carbonate group were elucidated to optimize the condition by using the model compounds, 3-cyclohexylpropyl 2-(9-fluorenylmethoxycarbonylamino)ethyl thioether and 3-(1,3-dioxan-2-one-5-yl)propyl ethyl thioether.

Polimeryzacja i kopolimeryzacja szescioczłonowych cyklicznych weglanow wobec katalizatorow koordynacyjnych

Polimeryzacja i kopolimeryzacja szescioczłonowych cyklicznych weglanow wobec katalizatorow koordynacyjnych

Polyaddition behavior of bis(five- and six-membered cyclic carbonate)s with diamine

Polyadditions of 1,2-bis[3-(1,3-dioxan-2-one-5-yl)-propylthio]ethane (B6CC) and 1,2-bis[4-(1,3-dioxolan-2-one-4-yl)-butylthio]ethane (B5CC) with 4,9-dioxadodecane-1,12-diamine were carried out. The reactivity of B6CC with the diamine was higher than that of B5CC. Additionally, B6CC gave a higher molecular weight polymer than B5CC. The reaction-rate constants of B6CC and B5CC at 30, 50, and 70 °C were evaluated as 0.70, 0.89, and 1.07 L/mol · h; and 0.03, 0.06, and 0.10 L/mol · h in N,N-dimethylacetamide (initial reagent concentration 0.5 M), respectively. The activation energies were estimated to be 9.2 and 24.9 kJ/mol in the reactions of B6CC and B5CC with the diamine, respectively. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 860–867, 2001

Novel ring-opening polymerization and its application to polymeric materials

Ring-opening polymerization of cyclic carbonates was studied. Volume expansion during polymerization of cyclic carbonates could be explained by the difference between intermolecular interaction of monomers and polymers, which was evaluated by dipole moment. A seven-membered cyclic carbonate polymerized much faster than a six-membered one. Bulky substituents of six-membered cyclic carbonates increased the equilibrium monomer concentration. A novel initiator system, combination of alcohol and trifluoroacetic acid, efficiently polymerized cyclic carbonates.

ChemInform Abstract: Highly Enantioselective Preparation of C2-Symmetrical Diols: Microbial Hydrolysis of Cyclic Carbonates.

Abstract A new type of microbial enantioselective hydrolysis of C 2 -symmetrical cyclic carbonates is disclosed. During the screening test of the five-membered substrate (4,5-dimethyl-1,3-dioxolan-2-one 5 ), Pseudomonas diminuta was selected as the best strain to perform the stereoselective hydrolysis. The reaction of dl - 5 with this microorganism in aqueous media containing THF as the co-solvent afforded ( S , S )- 5 and ( R , R )-butanediol 1 in excellent yields. It was found that the ring size did not affect the reactivity and enantioselectivity although the enzyme had a high substrate specificity for the side chain. A six-membered cyclic carbonate, dl -4,6-dimethyl-1,3-dioxan-2-one 6 , was smoothly hydrolyzed with higher enantioselectivity to afford the optically active ( S , S )- 6 and ( R , R )-2,4-pentanediol 2 .

New route to oligocarbonate diols suitable for the synthesis of polyurethane elastomers

Oligo(trimethylene carbonate) and oligo(neopentyl carbonate) diols were obtained by the polymerisation of corresponding six-membered cyclic carbonates in the presence of catalysts prepared in the reaction of water with diethylzinc or triethylaluminium. Their structures were proven by means of MALDI TOF and NMR spectroscopic studies. The oligocarbonate diols were reacted with 4,4′-methylenebis(phenyl isocyanate) in the presence of 1,4-butanediol as the chain extender to obtain polyurethane elastomers. The physical and mechanical properties and hydrolytic stability of novel polyurethane elastomers were compared with those of conventional materials based on polyester type soft segments.

Highly enantioselective preparation of C2-symmetrical diols: microbial hydrolysis of cyclic carbonates

A new type of microbial enantioselective hydrolysis of C 2-symmetrical cyclic carbonates is disclosed. During the screening test of the five-membered substrate (4,5-dimethyl-1,3-dioxolan-2-one 5), Pseudomonas diminuta was selected as the best strain to perform the stereoselective hydrolysis. The reaction of dl- 5 with this microorganism in aqueous media containing THF as the co-solvent afforded ( S, S)- 5 and ( R, R)-butanediol 1 in excellent yields. It was found that the ring size did not affect the reactivity and enantioselectivity although the enzyme had a high substrate specificity for the side chain. A six-membered cyclic carbonate, dl-4,6-dimethyl-1,3-dioxan-2-one 6, was smoothly hydrolyzed with higher enantioselectivity to afford the optically active ( S, S)- 6 and ( R, R)-2,4-pentanediol 2.

Synthesis of Six-Membered Cyclic Carbonate Monomers by Disproportionation of 1,3-Bis(alkoxycarbonyloxy)propanes and Their Polymerization

Synthesis of Six-Membered Cyclic Carbonate Monomers by Disproportionation of 1,3-Bis(alkoxycarbonyloxy)propanes and Their Polymerization