- PROCESS FOR THE SYNTHESIS OF ISOCYANATE-FREE OMEGA-HYDROXY-URETHANES, ALPHA-OMEGA-DIURETHANES AND OLIGO (POLY)URETHANES
-
The synthesis of omega-hydroxyalkyl-urethanes, and of alfa-omega-diurethanes is reported which includes the reaction of diols with urea in presence of catalysts based on Ce at temperatures between 125 and 170°C over 4-8 h reaction time. A process for the production of oligomers of omega-hydroxyalkyl-urethanes is also reported based on the reaction of urea with diols in presence of Ce or Zr catalysts or Ce mixed oxides at 125-170°C over 4-20 h.
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-
Page/Page column 6-7
(2021/11/26)
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- Overcoming Barriers in Polycarbonate Synthesis: A Streamlined Approach for the Synthesis of Cyclic Carbonate Monomers
-
Accessing cyclic carbonate monomers on a large scale is critical for the development of any new carbonate-based materials platform. The synthesis of carbonate monomers can be a challenging and tedious endeavor requiring multiple synthetic steps and purifications. To address this, we report a drastically improved process for the synthesis of carbonate monomers via a two-step route that avoids the use of hazardous triphosgene or chloroformate reagents. This process enables rapid access to a broad array of functional groups on the carbonate monomer and the monomers generated from the procedure can readily be polymerized via ring-opening polymerization.
- Tan, Eddy W. P.,Hedrick, James L.,Arrechea, Pedro L.,Erdmann, Tim,Kiyek, Vivien,Lottier, Simon,Yang, Yi Yan,Park, Nathaniel H.
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p. 1767 - 1774
(2021/03/01)
-
- Ultrasound-assisted synthesis of a stable Co(II) coordination polymer as heterogeneous catalyst for CO2 transformation
-
A stable benzimidazole-containing Co(II) coordination polymer namely [Co(L)0.5(oba)]n (1) (H2oba = 4,4′-oxybis(benzoate), L = 1,6-bis(5,6-dimethylbenzimidazolyl) hexane) was successfully synthesized by ultrasonic technique under mild conditions. In especial, the effects of initial reagent concentration, irradiation time and ultrasonic power on the morphology and size of micron scale 1 were discussed in detail. Micron scale 1 appeared exceptional solvent and pH stabilities. Further, as a heterogeneous Lewis catalyst, 1 exhibited a highly activity and recyclability for CO2 transformation by cycloaddition with epoxide under room temperature.
- Liu, Ce,Liu, Lin,Han, Zheng-Bo
-
supporting information
(2021/01/18)
-
- Rational Design of Cobalt Complexes Based on the trans Effect of Hybrid Ligands and Evaluation of their Catalytic Activity in the Cycloaddition of Carbon Dioxide with Epoxide
-
A series of cobalt complexes are presented as effective catalysts for the synthesis of cyclic carbonates from epoxides and CO2. The catalytic potentials of the cobalt complexes, in combination with tetrabutylammonium bromide, have been demonstrated to solve some challenges in the synthesis of cyclic carbonates, including the room-temperature conversion of terminal epoxides and activation-challenging substrates such as internal epoxides and fatty acid derived epoxides. A key factor in the success of the strategy is the use of cobalt complexes that are prepared on the basis of the trans effect of hybrid ligands. The trans effect between N-heterocyclic carbenes and acetylacetone has been proved by a number of spectroscopic measurements, including UV-vis, ESI-MS, EPR, and in situ FT-IR and by DFT calculations; these support the notion that acetylacetone prefers to dissociate from the cobalt center, which will result in one coordination site for the activation of a substrate molecule at the cobalt atom and thus give rise to high reactivity.
- Bu, Qingqing,Dai, Bin,Liu, Ning,Liu, Qiuli,Song, Wen-Yue,Wei, Donghui
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p. 3546 - 3561
(2020/11/02)
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- Highly synergistic effect of ionic liquids and Zn-based catalysts for synthesis of cyclic carbonates from urea and diols
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The development of stable and efficient catalysts is an attractive topic for green chemistry reactions under mild reaction conditions. In order to improve solvent-free synthesis of cyclic carbonates from urea and diols, a binary catalyst systems of Zn-based and different ionic liquids (ILs) were developed and examined in this study. The yield of ethylene carbonate (EC) could reach to 92.2% in the presence of C16mimCl/ZnCl2 catalyst. Through exploring the structure-activity relationships of cation and anion, it was confirmed that a synergistic effect of cation and anion of catalyst had important influences on urea alcoholysis. Additionally, the controlling step of EC synthesis reaction involving the elimination of an ammonia molecule from intermediates had been revealed by in situ FT-IR. This could afford a guided insight for synthesizing cyclic carbonates with high yield. Furthermore, a possible mechanism for the catalytic process was proposed based on DFT and the experimental results via FT-IR, 1H-NMR and 13C NMR analysis, which revealed that not only a probable synergistic effects of cation-anion matters, but also C(2)-H of ILs and Zn2+ played a key role in accelerating the reaction of urea alcoholysis. This catalytic mechanism study is to provide a preliminary basis to develop novel catalysts for cyclic carbonates from urea and diols through a green synthetic pathway.
- Cheng, Weiguo,Deng, Lili,Dong, Li,He, Hongyan,Li, Zengxi,Qian, Wei,Shi, Zijie,Su, Qian,Sun, Wenzhong
-
-
- Supported Polyhedral Oligomeric Silsesquioxane-Based (POSS) Materials as Highly Active Organocatalysts for the Conversion of CO2
-
Very high turnover numbers (TON) and productivity values up to 7875 and 740 respectively have been obtained for the conversion of CO2 into cyclic carbonates by using hybrid materials based on imidazolium modified polyhedral oligomeric silsesquioxanes (POSS-Imi) grafted on amorphous silica (SiO2) and mesostructured SBA-15. The heterogeneous organocatalysts were easily prepared via a straightforward synthetic procedure allowing to generate high local concentration spots of imidazolium active sites surrounding the POSS core. This synthetic procedure is also a promising approach for the design of a wide library of hybrid functional materials. The materials do not possess other co-catalytic species with Lewis or Br?nsted acid functionalities which still represents a challenging aspect for the outcome of the process. The recyclability of the catalysts was successfully verified for four consecutive runs. The catalytic versatility was proved with a wide range of epoxides and with the most challenging oxetane on large scale (105–210 mmol) showing higher performances in comparison with other unmodified imidazolium-based catalytic systems. The new hybrids based on supported POSS nanostructures allowed the sustainable conversion of carbon dioxide under solvents- and metal-free reaction conditions with a full selectivity toward cyclic carbonates.
- Calabrese, Carla,Liotta, Leonarda F.,Giacalone, Francesco,Gruttadauria, Michelangelo,Aprile, Carmela
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p. 560 - 567
(2018/11/10)
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- METHOD FOR PRODUCING AROMATIC NITRILE COMPOUND AND METHOD FOR PRODUCING CARBONATE ESTER
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Provided is a method for regenerating an aromatic amide compound into a corresponding aromatic nitrile compound, the method realizing a dehydration reaction of providing a target compound selectively at a high yield with generation of a by-product being suppressed. Also provided is a method for producing an aromatic nitrile compound that decreases the number of steps of dehydration reaction and significantly improves the reaction speed at a pressure close to normal pressure. Furthermore, the above-described production method is applied to a carbonate ester production method to provide a method for producing carbonate ester efficiently. The above-described objects are achieved by a method for producing an aromatic nitrile compound including a dehydration reaction of dehydrating an aromatic amide compound, in which the dehydration reaction uses diphenylether.
- -
-
Paragraph 0113
(2019/07/03)
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- METHOD FOR PRODUCING AROMATIC NITRILE COMPOUND AND METHOD FOR PRODUCING CARBONIC ACID ESTER
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Provided is a method for regenerating an aromatic amide compound into a corresponding aromatic nitrile compound, the method realizing a dehydration reaction of providing a target compound selectively at a high yield, with generation of a by-product being suppressed. Also provided is a method for producing an aromatic nitrile compound that decreases the number of steps of the dehydration reaction and significantly improves the reaction speed even at a pressure close to normal pressure. In addition, the above-described production method is applied to a carbonate ester production method to provide a method for producing a carbonate ester efficiently. The above-described methods are realized by a method for producing an aromatic nitrile compound including a dehydration reaction of dehydrating an aromatic amide compound, in which the dehydration reaction uses, as a solvent, any of 1,2-dimethoxybenzene, 1,3-dimethoxybenzene and 1,3,5-trimethoxybenzene.
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-
Paragraph 0165-0166
(2020/01/08)
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- Visible-Light-Mediated Liberation and In Situ Conversion of Fluorophosgene
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The first example for the photocatalytic generation of a highly electrophilic intermediate that is not based on radical reactivity is reported. The single-electron reduction of bench-stable and commercially available 4-(trifluoromethoxy)benzonitrile by an organic photosensitizer leads to its fragmentation into fluorophosgene and benzonitrile. The in situ generated fluorophosgene was used for the preparation of carbonates, carbamates, and urea derivatives in moderate to excellent yields via an intramolecular cyclization reaction. Transient spectroscopic investigations suggest the formation of a catalyst charge-transfer complex-dimer as the catalytic active species. Fluorophosgene as a highly reactive intermediate, was indirectly detected via its next downstream carbonyl fluoride intermediate by NMR. Furthermore, detailed NMR analyses provided a comprehensive reaction mechanism including a water dependent off-cycle equilibrium.
- Petzold, Daniel,Nitschke, Philipp,Brandl, Fabian,Scheidler, Veronica,Dick, Bernhard,Gschwind, Ruth M.,K?nig, Burkhard
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supporting information
p. 361 - 366
(2018/11/23)
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- Metal free synthesis of ethylene and propylene carbonate from alkylene halohydrin and CO2 at room temperature
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Herein we describe a metal free and one-pot pathway for the synthesis of industrially important cyclic carbonates such as ethylene carbonate (EC) and propylene carbonates (PC) from molecular CO2 under mild reaction conditions. In the actual synthesis, the alkylene halohydrins such as alkylene chloro- or bromo or iodohydrin and organic superbase, 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU) reacted equivalently with CO2 at room temperature. The syntheses of cyclic carbonates were performed in DMSO as a solvent. Both 1,2 and 1,3 halohydrin precursors were converted into cyclic carbonates except 2-bromo- and iodoethanol, which were reacted equivalently with DBU through n-alkylation and formed corresponding n-alkylated DBU salts instead of forming cyclic carbonates. NMR analysis was used to identify the reaction components in the reaction mixture whereas this technique was also helpful in terms of understanding the reaction mechanism of cyclic carbonate formation. The mechanistic study based on the NMR analysis studies confirmed that prior to the formation of cyclic carbonate, a switchable ionic liquid (SIL) formed in situ from alkylene chlorohydrin, DBU and CO2. As a representative study, the synthesis of cyclic carbonates from 1,2 chlorohydrins was demonstrated where the synthesis was carried out using chlorohydrin as a solvent as well as a reagent. In this case, alkylene chlorohydrin as a solvent not only replaced DMSO in the synthesis but also facilitated an efficient separation of the reaction components from the reaction mixture. The EC or PC, [DBUH][Cl] as well as an excess of the alkylene chlorhydrin were separated from each other following solvent extraction and distillation approaches. In this process, with the applied reaction conditions, >90% yields of EC and PC were achieved. Meanwhile, DBU was recovered from in situ formed [DBUH][Cl] by using NaCl saturated alkaline solution. Most importantly here, we developed a metal free, industrially feasible CO2 capture and utilization approach to obtain EC and PC under mild reaction conditions.
- Khokarale, Santosh Govind,Mikkola, Jyri-Pekka
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p. 34023 - 34031
(2019/11/11)
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- Mechanochemical synthesis of poly(trimethylene carbonate)s: An example of rate acceleration
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Mechanochemical polymerization is a rapidly growing area and a number of polymeric materials can now be obtained through green mechanochemical synthesis. In addition to the general merits of mechanochemistry, such as being solvent-free and resulting in high conversions, we herein explore rate acceleration under ball-milling conditions while the conventional solution-state synthesis suffer from low reactivity. The solvent-free mechanochemical polymerization of trimethylene carbonate using the organocatalysts 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) are examined herein. The polymerizations under ball-milling conditions exhibited significant rate enhancements compared to polymerizations in solution. A number of milling parameters were evaluated for the ball-milling polymerization. Temperature increases due to ball collisions and exothermic energy output did not affect the polymerization rate significantly and the initial mixing speed was important for chain-length control. Liquid-assisted grinding was applied for the synthesis of high molecular weight polymers, but it failed to protect the polymer chain from mechanical degradation.
- Park, Sora,Kim, Jeung Gon
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p. 963 - 970
(2019/06/08)
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- A Guiding Principle for Strengthening Crosslinked Polymers: Synthesis and Application of Mobility-Controlling Rotaxane Crosslinkers
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Three component mobility controlling vinylic rotaxane crosslinkers with two radically polymerizable vinyl groups (RC_Rs) were synthesized to prove that the mobility of the components of the RC_Rs plays a crucial role in determining the properties of rotaxane-crosslinked polymers (RCPs). RC_Rs (R=H, Me, or Et) were obtained from living ring-opening polymerization. RCP_Et was prepared using RC_Et, which exhibits the lowest component mobility. The low component mobility is reflected in inferior mechanical strength and stretching ability in tensile stress tests compared to components with good (R=Me) and high (R=H) mobility. However, RCP_Et exhibited significantly higher stress and strain values than the corresponding covalently crosslinked polymers (CCP_Rs). These results indicate that a suitable component mobility substantially enhances the mechanical strength of RCPs. This behavior could serve as a guiding principle for the molecular design of advanced RCs.
- Sawada, Jun,Aoki, Daisuke,Otsuka, Hideyuki,Takata, Toshikazu
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supporting information
p. 2765 - 2768
(2019/02/01)
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- Cooperative Multifunctional Organocatalysts for Ambient Conversion of Carbon Dioxide into Cyclic Carbonates
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A series of pincer-type compounds possessing an N-heterocyclic carbene precursor and a carboxyl group as proton transfer agent were synthesized and used as organocatalysts for the cycloaddition of epoxides with CO2. In this context, we have demonstrated the high activity of these one-component organocatalysts in the CO2 transformation to cyclic carbonates under ambient conditions (room temperature, 1 bar of CO2). The catalytic potential of these multifunctional organocatalysts on challenging internal epoxides is particularly deserving of mention because organocatalysts that are able to mediate the cycloaddition reaction of internal epoxides with CO2 under mild conditions remain scarce. The intramolecular synergistic activation mechanism was elucidated by control experiments and DFT calculations.
- Liu, Ning,Xie, Ya-Fei,Wang, Chuan,Li, Shi-Jun,Wei, Donghui,Li, Min,Dai, Bin
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p. 9945 - 9957
(2018/10/15)
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- Carbon Dioxide Utilisation for the Synthesis of Unsymmetrical Dialkyl and Cyclic Carbonates Promoted by Basic Ionic Liquids
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An efficient and greener synthesis of unsymmetrical organic carbonates mediated by Hünig's base-appended basic ionic liquids, via carbon dioxide conversion, is described here. These ionic liquids were found to be effective bases for the fixation of carbon dioxide by various alcohols and benzyl bromide, at room temperature. When the alcohol and the halide functionalities are present within the same substrate, the reaction cleanly produces a cyclic carbonate. These functionalised basic ionic liquids were fully recyclable with no loss product yields.
- Goodrich, Peter,Gunaratne, H. Q. Nimal,Jin, Lili,Lei, Yuntao,Seddon, Kenneth R.
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p. 181 - 185
(2018/03/09)
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- Catalytic One-Pot Oxetane to Carbamate Conversions: Formal Synthesis of Drug Relevant Molecules
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Oxetanes are versatile building blocks in drug-related synthesis to induce property-modulating effects. Whereas related oxiranes are widely used in coupling chemistry with carbon dioxide (CO2) to afford value-added commodity chemicals, oxetane/CO2couplings remain extremely limited despite the recent advances in the synthesis of these four-membered heterocycles. Here we report an effective one-pot three-component reaction (3CR) strategy for the coupling of (substituted) oxetanes, amines and CO2to afford a variety of functionalized carbamates with excellent chemoselectivity and good yields. The process is mediated by an aluminium-based catalyst under relatively mild conditions and the developed catalytic methodology can be applied to the formal synthesis of two pharmaceutically relevant carbamates with the 3CR being a key step. (Figure presented.).
- Guo, Wusheng,Laserna, Victor,Rintjema, Jeroen,Kleij, Arjan W.
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supporting information
p. 1602 - 1607
(2016/10/13)
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- Selective formation of trimethylene carbonate (TMC): Atmospheric pressure Carbon dioxide utilization
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Carbon dioxide utilisation (CDU) is currently gaining increased interest due to the abundance of CO2 and its possible application as a C1 building block. We herein report the first example of atmospheric pressure carbon dioxide incorporation into oxetane to selectively form trimethylene carbonate (TMC), which is a significant challenge as TMC is thermodynamically less favoured than its corresponding co-polymer.
- Buckley, Benjamin R.,Patel, Anish P.,Wijayantha, K.G. Upul
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supporting information
p. 474 - 478
(2015/01/30)
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- New iron pyridylamino-bis(Phenolate) catalyst for converting CO2 into cyclic carbonates and cross-linked polycarbonates
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The atom-efficient reaction of CO2 with a variety of epoxides has been efficiently achieved employing iron pyridylamino-bis(phenolate) complexes as bifunctional catalysts. The addition of a Lewis base co-catalyst allowed significant reduction in the amount of iron complex needed to achieve high epoxide conversions. The possibility of controlling the selectivity of the reaction towards either cyclic carbonate or polycarbonate was evaluated. An efficient switch in selectivity could be achieved when cyclic epoxides such as cyclohexene oxide and the seldom explored 1,2-epoxy-4-vinylcyclohexane were used as substrates. The obtained poly(vinylcyclohexene carbonate) presents pending vinyl groups, which allowed post-synthetic cross-linking by reaction with 1,3-propanedithiol. The cross-linked polycarbonate displayed a substantial increase in the glass transition temperature and chemical resistance, thus opening new opportunities for the application of these green polymers. CO2 meets epoxides: Iron pyridylamino-bis(phenolate) complexes are highly active catalysts for the atom-efficient reaction of CO2 with a variety of epoxides. The selectivity can be switched between the cyclic or polymeric carbonate when using cyclic epoxides such as cyclohexene oxide and 1,2-epoxy-4-vinylcyclohexaneas substrates. Cross-linking of the obtained poly(vinylcyclohexene carbonate) leads to substantial increase in the Tg and chemical resistance of the polymer.
- Taherimehr, Masoumeh,Sert?, Jo?o Paulo Cardoso Costa,Kleij, Arjan W.,Whiteoak, Christopher J.,Pescarmona, Paolo P.
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p. 1034 - 1042
(2015/03/30)
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- Synthesis process of trimethylene carbonate from 1,3-propanediol and urea by heterogeneous catalysis
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The invention relates to the synthesis of trimethylene carbonate by reaction of alcoholysis of urea with 1,3-propanediol in liquid phase catalyzed by a mixed metal oxide comprising Zn and La. The catalyst used in the process of the invention is an intimate mixture of Zinc oxide (ZnO) and Lanthanum oxide (La2O3) leading, according to the molar ratio La:Zn ranging from 0.01 to 1.5, to a new mixed metal oxide comprising a solid solution of Lanthanum or Zinc in Zinc oxide or Lanthanum oxide, respectively, or to a spinel like structure when the molar ratio La/Zn is equal to 1. The solid mixed catalyst La:Zn improves both yield and selectivity of the reaction and makes easier the further step of separating the compounds of the reaction medium with an improved recovering rate in trimethylene carbonate.
- -
-
Paragraph 0046; 0059
(2015/05/26)
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- Development of complex approach to the synthesis of trimethylene carbonate as a monomer for biodegradable polymers
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With the aim of production of polymers for medicine a new preparation method was developed for trimethylene carbonate based on transesterification with trimethylene glycol of dialkyl carbonates obtained without the use of phosgene. As initial reagents alkylene carbonates or polycarbonates and titanium alkoxides can be utilized. The advantages of this approach consist in obtaining some additional useful substances and the possibility of reprocessing polycarbonate wastes.
- Kuznetsov,Pervova,Pestov
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p. 654 - 658
(2014/07/08)
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- Direct cyclic carbonate synthesis from CO2 and diol over carboxylation/hydration cascade catalyst of CeO2 with 2-cyanopyridine
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We first achieved direct synthesis of propylene carbonate from CO 2 and 1,2-propanediol in excellent yield (>99%) using a carboxylation/hydration cascade catalyst of CeO2 with 2-cyanopyridine. The catalyst system can be applied to syntheses of various cyclic carbonates, including 6-membered ring carbonates that are difficult to synthesize in high yields (62->99%).
- Honda, Masayoshi,Tamura, Masazumi,Nakao, Kenji,Suzuki, Kimihito,Nakagawa, Yoshinao,Tomishige, Keiichi
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p. 1893 - 1896
(2014/06/24)
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- SYNTHESIS OF CYCLIC CARBONATES
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The present invention provides a method of synthesizing a cyclic carbonate comprising the step of reacting an alcohol with carbon dioxide.in the presence of a base.
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Page/Page column 23; 25
(2014/11/11)
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- A powerful aluminum catalyst for the synthesis of highly functional organic carbonates
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An aluminum complex based on an amino triphenolate ligand scaffold shows unprecedented high activity (initial TOFs up to 36 000 h-1), broad substrate scope, and functional group tolerance in the formation of highly functional organic carbonates prepared from epoxides and CO2. The developed catalytic protocol is further characterized by low catalyst loadings and relative mild reaction conditions using a cheap, abundant, and nontoxic metal.
- Whiteoak, Christopher J.,Kielland, Nicola,Laserna, Victor,Escudero-Adán, Eduardo C.,Martin, Eddy,Kleij, Arjan W.
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supporting information
p. 1228 - 1231
(2013/03/14)
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- Synthesis of cyclic carbonates with carbon dioxide and cesium carbonate
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Cyclic carbonates are important compounds for the synthesis of biocompatible polymers and linear dialkyl carbonates, as well as solvents and electrolytes. We report here the synthesis of such compounds from easily accessible starting materials with carbon dioxide as a C1 source and caesium carbonate as the base. This new methodology is able to yield 5- and 6-membered cyclic carbonates very efficiently in a green manner.
- Reithofer, Michael R.,Sum, Yin Ngai,Zhang, Yugen
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p. 2086 - 2090
(2013/09/24)
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- An efficient iron catalyst for the synthesis of five- and six-membered organic carbonates under mild conditions
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An iron(III) amine triphenolate complex, [FeTPhOA]2, able to efficiently catalyze the cycloaddition of carbon dioxide to a range of terminal epoxides under mild conditions, is described. In addition, it has also been found that the complex is able to catalyze the conversion with more sterically congested oxiranes and oxetanes which are generally considered challenging substrates to activate. Variation of the co-catalyst, required for ring-opening of the substrates, has also been examined. The results show that terminal epoxide substrates are converted more efficiently with an iodide co-catalyst, whereas more bulky oxirane substrates give better product yields in the presence of a bromide co-catalyst. The combined results demonstrate the broad applicability of these iron(III) complexes in this type of carbon dioxide fixation chemistry. Copyright
- Whiteoak, Christopher J.,Martin, Eddy,Belmonte, Marta Martinez,Benet-Buchholz, Jordi,Kleij, Arjan W.
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experimental part
p. 469 - 476
(2012/04/04)
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- METHOD FOR PRODUCING CYCLIC CARBONATES
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Linear or cyclic carbonates as potential monomers for isocyanate-free polyurethanes and polycarbonates were prepared from polyols and dialkylcarbonatesor diphenyl carbonates. This invention was developed to produce linear or cyclic carbonates with or without using catalysts. Polyol compounds were reacted with carbonates such as dimethylcarbonate and diethylcarbonate to produce thecorresponding linear and/or cyclic carbonate.
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Page/Page column 16
(2012/12/13)
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- Selective, green synthesis of six-membered cyclic carbonates by lipase-catalyzed chemospecific transesterification of diols with dimethyl carbonate
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A facile and green synthesis of six-membered cyclic carbonates, the potential monomers for isocyanate-free polyurethanes and polycarbonates, was achieved by transesterification of diols with dimethyl carbonate catalyzed by immobilized Candida antarctica lipase B, Novozym435, followed by thermal cyclization in a solvent-free medium. The difference in the chemospecificity of the lipase for the primary, secondary and tertiary alcohols as acyl acceptors was utilized to obtain a highly chemoselective synthesis of the cyclic carbonate in high yield. In the lipase-catalyzed reaction with diols, the product contained almost equal proportions of mono- and di-carbonates with 1,3-propanediol having two primary alcohols, a higher proportion of mono-carbonate with 1,3-butanediol having a primary and a secondary alcohol, and mainly mono-carbonate with 3-methyl-1,3-butanediol having a primary and a tertiary alcohol. The chemospecificity of cyclic carbonates formed by thermal treatment at 90 °C was closely related to the proportion of mono-carbonate. The yield of cyclic carbonate was 99.3% with 3-methyl-1,3-butanediol, 85.5% with 1,3-butanediol, and 43.2% with 1,3-propanediol. Copyright
- Pyo, Sang-Hyun,Hatti-Kaul, Rajni
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experimental part
p. 797 - 802
(2012/05/04)
-
- Preparation and characterization of polyester- and poly(ester-carbonate)- paclitaxel conjugates
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The polyester- and poly(ester-carbonate)-paclitaxel conjugates with low molecular weight were synthesized using dicyclohexylcarbodiimide (DCC) and dimethylaminopyridine (DMAP) as catalysts. Polymeric matrices were obtained by ring-opening polymerization of ε-caprolactone (CL), rac-lactide (rac-LA), l-lactide (LLA) and trimethylene carbonate (TMC). The macromolecular conjugates were characterized by using spectroscopic techniques, such as 1H, 13C NMR and FTIR. The degree of degradation of polyester- and poly(ester-carbonate)-paclitaxel conjugates was tested in vitro under different conditions. The preliminary results of drug release were discussed.
- Sobczak, Marcin,Korzeniowska, Agnieszka,Go?, Piotr,Kolodziejski, Waclaw L.
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body text
p. 3047 - 3051
(2011/07/08)
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- A general and expedient synthesis of 5- and 6-membered cyclic carbonates by palladium-catalyzed oxidative carbonylation of 1,2- and 1,3-diols
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We present a general, practical, and efficient approach to 5- and 6-membered organic carbonates by palladium-catalyzed direct oxidative carbonylation of 1,2- and 1,3-diols, respectively. Reactions were carried out at 100 °C in N,N-dimethylacetamide as the solvent under 20 atm (at 25 °C; 1 atm=101.3 kPa) of a 4:1 v/v CO/air mixture in the presence of 0.5-2 mol % of PdI2 and KI (KI/PdI2 molar ratio=10). Excess dehydrating agent, such as trimethyl orthoacetate, was necessary in several cases to obtain appreciable results. The method could also be applied to the synthesis of a high-value-added glycerol carbonate from glycerol, a readily available raw material. When applied to α-D-glucose, a double carbonylation process took place, with direct formation of α-D-glucofuranose 1,2:5,6-dicarbonate.
- Gabriele, Bartolo,Mancuso, Raffaella,Salerno, Giuseppe,Veltri, Lucia,Costa, Mirco,Dibenedetto, Angela
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experimental part
p. 1778 - 1786
(2012/04/04)
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- Palladium-catalyzed carbonylation of diols to cyclic carbonates
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The catalytic alkoxycarbonylation of 1,2-diols by (neocuproine) palladium(II) acetate (neocuproine=2,9-dimethyl-1,10-phenanthroline) or palladium(II) acetate/(-)-sparteine using N-chlorosuccinimide as the oxidant affords cyclic carbonates. The oxidative carbonylation of diols proceeds under mild conditions, requiring only 1 atm of carbon monoxide, and produces cyclic carbonates in moderate to good yields. Both 1,2- and 1,3-diols can be carbonylated using (neocuproine)Pd(OAc)2 and sodium dichloroisocyanuric acid, which serves as a competent oxidant and base for this system, to yield 5- and 6-membered cyclic carbonates. Copyright
- Pearson, David M.,Conley, Nicholas R.,Waymouth, Robert M.
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supporting information; experimental part
p. 3007 - 3013
(2011/12/16)
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- A facile catalytic synthesis of trimethylene carbonate from trimethylene oxide and carbon dioxide
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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.
- Darensbourg, Donald J.,Horn Jr., Adolfo,Moncada, Adriana I.
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experimental part
p. 1376 - 1379
(2010/10/03)
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- Method for Making Carbonates and Esters
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A method for forming a monomeric carbonate includes the step of combining a monofunctional alcohol or a difunctional diol with an ester-substituted diaryl carbonate to form a reaction mixture. Similarly, a method for forming a monomeric ester includes the step of combining a monofunctional carboxylic acid or ester with an ester-substituted diaryl carbonate to form a reaction mixture. These methods further include the step of allowing the reaction mixtures to react to form a monomeric carbonate or a monomeric ester, respectively.
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Page/Page column 8
(2010/06/13)
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- Product study of the OH radical and Cl atom initiated oxidation of 1,3-dioxane
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The products of the hydroxyl (OH) radical and chlorine (Cl) atom initiated oxidation of 1,3-dioxane are determined under various reaction conditions in a 50 L teflon reaction chamber using FTIR spectroscopy for analysis. The major products detected in all experiments are (2-oxoethoxy)methyl formate, formic acid and methylene glycol diformate with average molar yields of 0.50±0.05, 0.41±0.02 and 0.03±0.01 respectively for the OH initiated oxidation in the presence of NOx. The yields of these products do not vary significantly with O2 partial pressure or oxidising agent (OH or Cl). However, the yield of formic acid decreased by at least a factor of two in the absence of NOx. The results of these experiments are used to elucidate a simplified gas-phase atmospheric degradation scheme for 1,3-dioxane and also provide valuable information on the atmospheric fate of the cyclic and linear alkoxy radicals produced in these and similar reactions. The available experimental data suggests that the relative importance of the competing pathways (reaction with O2 and ring opening by C-C or C-O bond fission) is a strong function of the ring strain in the cycloalkoxy radicals.
- Moriarty, Jennie,Wenger, John C.,Sidebottom, Howard W.
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experimental part
p. 3980 - 3986
(2011/10/02)
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- A novel and efficient method for the catalytic direct oxidative carbonylation of 1,2- and 1,3-diols to 5-membered and 6-membered cyclic carbonates
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In the presence of a PdI2-based catalytic system, 1,2-diols undergo an oxidative carbonylation process to afford 5-membered cyclic carbonates in good to excellent yields (84-94%) and with unprecedented catalytic efficiencies for this kind of reaction (up to ca. 190 mol of product per mol of PdI2). Under similar conditions, 6-membered cyclic carbonates are obtained for the first time through a direct catalytic oxidative carbonylation of 1,3-diols (66-74% yields).
- Gabriele, Bartolo,Mancuso, Raffaella,Salerno, Giuseppe,Ruffolo, Giuseppe,Costa, Mirco,Dibenedetto, Angela
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experimental part
p. 7330 - 7332
(2010/02/28)
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- Mechanistic studies of the copolymerization reaction of oxetane and carbon dioxide to provide aliphatic polycarbonates catalyzed by (salen)CrX complexes
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Chromium salen derivatives in the presence of anionic initiators have been shown to be very effective catalytic systems for the selective coupling of oxetane and carbon dioxide to provide the corresponding polycarbonate with a minimal amount of ether linkages. Optimization of the chromium(III) system was achieved utilizing a salen ligand with tert-butyl groups in the 3,5-positions of the phenolate rings and a cyclohexylene backbone for the diimine along with an azide ion initiator. The mechanism for the coupling reaction of oxetane and carbon dioxide has been studied. Based on binding studies done by infrared spectroscopy, X-ray crystallography, kinetic data, end group analysis done by 1H NMR, and infrared spectroscopy, a mechanism of the copolymehzation reaction is proposed. The formation of the copolymer is shown to proceed in part by way of the intermediacy of trimethylene carbonate, which was observed as a minor product of the coupling reaction, and by the direct enchainment of oxetane and CO2. The parity of the determined free energies of activation for these two processes, namely 101.9 kJ·mol-1 for ring-opening polymerization of trimethylene carbonate and 107.6 kJ·mol-1 for copolymerization of oxetane and carbon dioxide supports this conclusion.
- Darensbourg, Donald J.,Moncada, Adriana I.,Choi, Wonsook,Reibenspies, Joseph H.
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p. 6523 - 6533
(2008/12/22)
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- Selective pyrolysis of bifunctional compounds: gas-phase elimination of carbonate-ester functionalities
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Compounds containing both carbonate and ester functionalities were synthesized and then subjected to online-GC gas-phase pyrolysis. The carbonate groups were cleaved selectively in all elimination reactions. The end products of the reaction were found to be affected by the nature of the substrate. The presence of hydrogen and carbonyl substituents on the carbon β to the carbonate group resulted in further product decomposition through a concerted six-membered transition state. Results from flash vacuum pyrolysis (FVP) and analysis of the GC data indicate that the cleavage of the carbonate group is fast, and that the slower secondary decomposition reactions are independent of the presence of the carbonate group. Spectroscopic analyses of the products are reported.
- Al-Azemi, Talal F.,Dib, Hicham H.,Al-Awadi, Nouria A.,El-Dusouqui, Osman M.E.
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p. 4126 - 4134
(2008/09/20)
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- Synthesis and thermolysis of a spiro-fused oxadiazoline - Evidence for sequential formation of carbene and oxirane intermediates, and for oxirane dimerization
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The spiro-fused oxadiazoline, 3,4-diaza-2,2-dimethyl-1,6,10-trioxaspiro[4. 5]dec-3-ene, when thermolysed in a sealed tube in benzene-d6 at 110 °C, afforded acetone and an apparent oxirane intermediate (2,2-dimethyl-1,4,8-trioxaspiro[2.5]octane) that could not be isolated. Attempts to isolate the oxirane gave a dimer (8,8,11,11-tetramethyl-1,5,7,10,12,16- hexaoxadispiro[5.2.5.2]hexadecane) as the major product. The oxirane is thermally stable at 110 °C but it is very sensitive to water, as indicated by its gradual disappearance after the tube was opened. The dimer of the oxirane is believed to form from a cation arising from the ring-opening of the oxirane when it reacts with moisture. This cation then reacts with the oxirane itself to regenerate water, which is effectively a catalyst for conversion of the oxirane to the dimer.
- Klys, Arkadiusz,Czardybon, Wojciech,Warkentin, John,Werstiuk, Nick Henry
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p. 1769 - 1773
(2007/10/03)
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- Method of making trimethylene carbonate
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A method of synthesizing trimethylene carbonate is disclosed involving (a) reacting 1,3-propanediol and a compound chosen from phosgene and bis-chloroformates to form a polycarbonate intermediate having the structure: wherein n is at least 2; R1is an end group chosen from H, R3-Cl, R3-OH and —C(O)Cl, where R3is C1-C6linear or branched alkyl and R2is an end group chosen from —OCH2CH2CH2Cl, —OCH2CH2CH2OH and Cl; and (b) providing a combination of temperature and pressure corresponding to vapor phase conditions for trimethylene carbonate.
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- Di-tert-butyl dicarbonate and 4-(dimethylamino)pyridine revisited. Their reactions with amines and alcohols
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The reaction of BOC2O in the presence and absence of DMAP was examined with some amines, alcohols, diols, amino alcohols, and aminothiols. Often, unusual products were observed depending on the ratio of reagents, reaction time, polarity of solvent, pK(a) of alcohols, or type of amine (primary or secondary). In reactions of aliphatic alcohols with BOC2O/DMAP, we isolated for the first time carbonic-carbonic anhydride intermediates; this helps explain the formation of symmetrical carbonates in addition to the O-BOC products. In the case of secondary amines, we succeeded to isolate unstable carbamic-carbonic anhydride intermediates that in the presence of DMAP led to the final N-BOC product. The effect of N-methylimidazole in place of DMAP was also examined.
- Basel, Yochai,Hassner, Alfred
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p. 6368 - 6380
(2007/10/03)
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- Experimental Evidence for the Stereoelectronically Controlled Hydrolysis of Orthocarbonates
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The acid hydrolysis of cyclic and acyclic orthoesters 1-6 is reported.The results obtained are explained by taking into account the principle of stereoelectronic control.
- Li, Shigui,Deslongchamps, Pierre
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p. 5641 - 5644
(2007/10/02)
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- Process for the preparation of trimethylene carbonate
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A process for producing trimethylene carbonate wherein 1,3-propanediol is reacted with diethylcarbonate in the presence of zinc powder, zinc oxide, tin powder, tin halide or an organo-tin compound, at an elevated temperature.
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- The Cycloaddition of Heterocumulenes to Oxetanes in the Presence of Catalytic Amounts of Tetraphenylstibonium Iodide
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The cycloadditions of carbon dioxide, isocyanates and carbodiimides to oxetanes proceeded in the presence of catalytic amounts of tetraphenylstibonium iodide (1) under mild conditions, affording the corresponding six-membered heterocycles; 1,3-dioxan-2-ones, 1,3-oxazin-2-ones and 1,3-oxazin-2-imines in good yields, respectively.Moreover, the cycloaddition of 2-phenyloxetane proceeded via predominant ring-cleavage at substituted site.
- Fujiwara, Masahiro,Baba, Akio,Matsuda, Haruo
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p. 1659 - 1663
(2007/10/02)
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- CYCLOADDITION OF OXETANE AND CARBON DIOXIDE CATALYZED BY TETRAPHENYLSTIBONIUM IODIDE
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Trimethylene carbonate was readily obtained in the reaction of oxetane and carbon dioxide in the presence of tetraphenylstibonium iodide.
- Baba, Akio,Kashiwagi, Hiroki,Matsuda, Haruo
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p. 1323 - 1324
(2007/10/02)
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- TRANSFORMATIONS OF CYCLIC ORTHO MONO- AND DIESTERS BY THE ACTION OF FREE RADICALS IN THE LIQUID PHASE
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The homolytic liquid-phase reactions of 2-propoxy-1,3-dioxane, 1,2-di(1,3-dioxolan-2-yloxy)ethane, and 1,3-di(1,3-dioxan-2-yloxy)propane, initiated by tert-butoxyl radicals, were investigated.A mechanism is proposed for the formation of dipropylcarbonate, 1,3-dioxan-2-one, propylformate, propionaldehyde, and propane from 2-propoxy-1,3-dioxane.The kinetic parameters characterizing the rate and direction of the transformations were determined.It was found that the corresponding linear and cyclic carbonates are mainly formed from the ortho diesters.
- Kostyukevich, L. L.,Pastuschenko, E. V.,Zlot-skii S. S.,Rakhmankulov, D. L.
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p. 127 - 132
(2007/10/02)
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- A FACILE PREPARATION OF DIALKYL CARBONATES FROM POTASSIUM CARBONATE AND ALKYL BROMIDES BY USING ORGANOSTANNYL COMPOUND AS A CATALYST
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Dialkyl carbonates were easily prepared by the heterogeneous reaction of solid potassium carbonate with alkyl bromides in dimethylformamide or dimethylsulfoxide in the presence of organostannyl compound such as hexabutyldistannoxane or chlorotributylstannane.Mixed catalytic system consisting of a tributylstannyl compound and 18-Crown-6 was much effective even in less polar solvents.
- Fujinami, Tatsuo,Sato, Shinichi,Sakai, Shizuyoshi
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p. 749 - 752
(2007/10/02)
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