Ratio Of Propylene Oxide Research Articles

Facile and direct synthesis of oligocarbonate diols from carbon dioxide and their application as sustainable feedstock for polyurethane

Oligocarbonate diols (PPCDL) with carbonate content higher than 90% were successfully synthesized by the direct copolymerization of propylene oxide (PO) and carbon dioxide (CO2) using metal-free Lewis acid-base catalysts in the presence of 1,4-butanediol (BDO) as proton exchange agent (PEA). The effects of molar ratio of PO to BDO, temperature, pressure and reaction time on the copolymerization were systematically investigated. The molecular weight of the prepared oligocarbonate diols is in good linear relationship to PO/BDO feeding ratio and can be easily and precisely controlled in the range of 1000–4000 g mol−1. The detailed structures of the oligocarbonate diols were fully investigated by 1H NMR, 13C NMR, MALDI-TOF analysis. The rheological properties of synthesized PPCDL were also studied using a rheometer. Finally, polycarbonate urethanes were designed and successfully prepared using the PPCDLs as soft segment and 4,4′-diphenylmethane diisocyanate (MDI) and BDO as hard segment. The comprehensive evaluation of thermal and mechanical properties of the synthesized poly(carbonate urethane)s (PCUs) demonstrates their complete feasibility in the application of polyurethane industry.

Investigation of dual modification on physicochemical, morphological, thermal, pasting, and retrogradation characteristics of sago starch.

The aim of this study was to evaluate the characteristics of dually modified sago starch by acid hydrolysis (AH)‐hydroxypropylation (HP). For this purpose, sago starch was modified with the combination by AH (5–20 h hydrolysis times) followed by HP (5%–25% ratio of propylene oxide) processes. The results showed that the dual modification of the sago starch structure didn't have a significant effect on the size of starch granules, and the granule size was in the range of 0.005–0.151 µm; however, the pasting properties and the glass transition temperature decreased significantly (p < .05). Increasing the level of propylene oxide from 5% to 25% caused a significant increase in the substitution degree (DS) and swelling ability of starches and reduced the syneresis, while with increasing acid hydrolysis time from 5 h to 20 h, starch swelling decreased and syneresis increased (p < .05). AH process at high hydrolysis times (20 h) increased the gelatinization temperatures and decreased retrogradation temperatures. Increasing the level of propylene oxide in both single and dual modification reduced the temperatures and enthalpy of gelatinization and retrogradation of sago starch. In summary, dually modified sago starch has a great potential to use in specific food products such as frozen dough or frozen bakery products.

Effective extraction of tylosin and spiramycin from fermentation broth using thermo-responsive ethylene oxide/propylene oxide aqueous two-phase systems.

Recyclable aqueous two-phase systems with thermo-responsive phase-forming materials have been employed to separate macromolecules; however, these systems have achieved very limited separation efficiency for small molecules, such as antibiotics. In this study, aqueous two-phase systems composed of the ethylene oxide/propylene oxide copolymer and water were developed to extract alkaline antibiotics from the fermentation broth. In the aqueous two-phase systems with an ethylene oxide ratio of 20 and propylene oxide ratio of 80, the partition coefficients of tylosin and spiramycin reached 16.87 and 20.39, respectively, while the extraction recoveries were 70.67 and 86.70%, respectively. Coupled with mechanism analysis, we demonstrated the feasibility of extracting alkaline antibiotics using this aqueous two-phase system, especially for 16-membered macrolide antibiotics. The molecular dynamic simulation was employed to visualize the process of dual-phase formation and the partition behavior of antibiotics in an aqueous two-phase system. The dynamic simulation revealed the binding energy between the antibiotic and ethylene oxide/propylene oxide copolymers, which provides a simple indicator for screening suitable antibiotics in aqueous two-phase systems. Our recyclable aqueous two-phase systems provide a robust approach for the extraction of 16-membered macrolide antibiotics with ease of operation and high recovery rates, which is appropriate for large-scale extraction in the fermentation industry.

Alternating terpolymerization of carbon dioxide, propylene oxide, and various epoxides with bulky side groups for the tuning of thermal properties

Terpolymerization of carbon dioxide (CO2), propylene oxide (PO), and epoxide with bulky side groups (styrene oxide (SO), cyclohexylethylene oxide (CyEO), tert-butylethylene oxide (tBuEO), or 1-adamantylethylene oxide (AdEO)) was conducted by using a tetraphenylporphyrinatocobalt(III) chloride ((TPP)CoCl)/4-dimethylamino pyridine (DMAP) catalyst system. Compared with the copolymerizations of CO2 and epoxides with bulky side groups, it took less than half (AdEO) or even one-third (CyEO and tBuEO) of the polymerization time to synthesize polycarbonates with degrees of polymerization of 100 or above. In this (TPP)CoCl/DMAP system, a highly random terpolymer of CO2, PO, and SO was realized for the first time, which has not been observed in other catalyst systems, such as cobalt salen complex systems. In contrast, gradient terpolymers were formed in the cases of CyEO, tBuEO, and AdEO. The glass transition temperatures (Tgs) of these terpolymers are tunable between that of the copolymer of CO2 with PO (34 °C) and that of the copolymer of CO2 with the corresponding epoxide with bulky side groups by changing the initial ratio of PO to epoxide with bulky side groups. A highly random terpolymer of CO2, styrene oxide (SO), and propylene oxide (PO) was realized by using a tetraphenylporphyrinatocobalt(III) chloride ((TPP)CoCl)/4-dimethylamino pyridine (DMAP) catalyst system. In contrast, gradient terpolymers were formed in the cases of CO2, cyclohexylethylene oxide (CyEO), tert-butylethylene oxide (tBuEO) or 1-adamantylethylene oxide (AdEO), and PO. The glass transition temperatures (Tgs) of these terpolymers are tunable between that of the copolymer of CO2 with PO (34 °C) and that of the copolymers of CO2 with the corresponding epoxide with bulky side groups.

Production and characterization of rigid polyurethane foam by oxypropylation of organosolv lignin extracted from exhausted olive pomace

Organosolv lignin has been extracted from spent olive-pomace and converted into polyols by oxypropylation in presence of potassium hydroxide. Reaction parameters such as temperature, catalyst contents and lignin / propylene oxide ratio [L / PO (w / v)] were optimized. The macro-polyols obtained were characterized by FTIR spectroscopy, 13C NMR, 1H NMR, and size exclusion chromatography. The intrinsic viscosity, the amount of poly (propylene oxide) homopolymer (PPO) and the hydroxyl number (IOH) were also determined. Olive pomace- lignin based rigid polyurethane foams (RPU) have been produced and characterized. A RPU displaying specifications close to those of commercial RPU in terms of compressive strength (1.9 Mpa), density (40 Kg.m−3) and thermal conductivity (27 mW.mK−1) was produced.

Adherence behavior of 1-poly(propylene oxide)-2-(1-pyrenyl)benzimidazoles on graphene oxide surface

1-Poly(propylene oxide)-2-(1-pyrenyl)benzimidazole (PyrBI-PPO(n), n denotes the degree of polymerization (DP) of poly(propylene oxide) (PPO)) was synthesized by the ring-opening polymerization of propylene oxide (PO) with NH-deprotonated 2-(1-pyrenyl)benzimidazole (PyrBI). The DP of the PPO chain depended on the feed ratio of PO/(NH-deprotonated PyrBI). The solubility of PyrBI-PPO(n) in water depended on the PPO chain length. The reaction of water-soluble PyrBI-PPO(n) (n = 26, 46, and 125) with graphene oxide (GO) in water at various feed ratios of GO/PyrBI-PPO(n) caused the adherence of the pyrenyl group on the GO surface and produced water-soluble composites, namely, PyrBI-PPO(n)-GO. The adherence behavior of PyrBI-PPO(n) on the GO surface was investigated by UV–vis and photoluminescence spectroscopy analyses.

Synthesis and foaming performance of one high-efficient air content regulator of concrete

The structure and number of air-voids in concrete can greatly affect the macroscopic performance of concrete. Therefore, the development of highly efficient concrete air content regulators, such as air-entraining agents or defoamers, is important. In this work, one novel block phenyloxy polyether with different propylene oxide (PO) units was successfully synthesized, and this kind of surfactants could be used as air-entraining agents or defoamers by controlling the ratio and position of PO in the polymer structure. The structures of these surfactants were verified by 1H NMR and infrared spectroscopy. Results of foamability and foam stability tests of these surfactants in water solutions indicated that the position and ratios of PO in the polymer structure have a remarkable effect on the foam properties of the surfactants. When these surfactants were applied to cement mortar, surfactant S4 with PO units adjacent to benzene ring group exhibited excellent air entrainment performance, whereas surfactants S8 and S9 with PO units at the end of the polymer showed obvious defoaming ability. The surface activity, adsorption and rheological properties were also tested to understand this type of surfactants. The results of concrete application and mechanism study showed that this type of surfactant had great potential for practical application.

Ethylene oxide based copolymers functionalized with terminal alkynes: Structure influence on their micelle formation

Copolymers from ethylene oxide (EO) and propylene oxide (PO) functionalized with glycidyl propargyl ether (GPE) are synthesized. The GPE allows further attachment of drugs but its influence on the polymeric micelle formation is unknown. In this work, the influence of the structure of these copolymers on their critical micellar concentration (CMC) in water and in the size and stability of obtained micelles is studied. For this purpose, the presence of GPE, the copolymer type (gradient or block), the EO:PO ratio and the initiator (water or ethanol) are modified. Gradient copolymers can be synthesized in a single step thanks to the different monomers reactivity, simplifying the process and obtaining similar CMC values to the block copolymers. The use of ethanol as initiator decreases the block copolymer CMC and increases the polydispersity. Besides, the presence of the GPE does not impede the micelle formation and has low effect on the copolymer CMCs. Finally, the higher the EO:PO ratio, the higher the CMC and the smaller the size of micelles. Moreover, Z-potential, DLS and HRSEM analyses show that the micelles are stable, spherical, capable to incorporate coumarin (a hydrophobic drug) and with apparent hydrodynamic sizes suitable to be absorbed by target cells.

Evaluation of Fatty Acid Waste in the Synthesis of Oligo(Ether-Ester)s

In this study, the waste of sunflower oil refinement was converted to a fatty acid glycidyl ester (FAGE). An unsaturated oligo(ether-ester) (OEE) was synthesized by ring-opening polymerization using propylene oxide (PO) and FAGE. Oligo(ether-ester) production was achieved with a high yield of 80% at 5 h and 0°C when the mole ratio of PO : FAGE was 1 : 1. Synthesized OEE was characterized by FTIR and several chemical analysis methods. According to the TGA results, T5, T10, and T50 values of OEE-styrene copolymers increased up to a 7 : 3 mole ratio then decreased. The weight losses of these copolymers changed in the range of 3-5%. The data of longitudinal and transversal wave velocities showed that copolymers with styrene had better elastic properties and impact resistances compared to those with pure polystyrene.

Double Ring‐Expanding Carbonylation Using an In Situ Generated Aluminum Phthalocyanine Cobalt Carbonyl Complex

AbstractThe ring‐expanding carbonylation of epoxides provides an efficient one‐step procedure for synthesizing β‐lactones and succinic anhydride derivatives. Although porphyrin‐based catalysts generally show excellent catalytic activities in the ring‐expanding carbonylation of epoxides, the application of porphyrin catalysts is limited owing to the low yield and high cost of preparing porphyrins. This study aims to propose a new and highly efficient catalytic system for the carbonylation of propylene oxide (PO) using an in situ generated active catalyst from cost‐effective and readily available aluminum phthalocyanine chloride (AlPcCl) and dicobalt octacarbonyl (Co2(CO)8). The catalyst showed not only excellent catalytic activities of single carbonylation but also double carbonylation resulting in anhydride by judicious choice of reaction parameters, such as reaction temperature and the ratio of PO to catalyst. This is the first report on the use of an in situ generated catalyst for the one‐pot double carbonylation of epoxide to anhydride.

Preparation of homogeneous mullite fibrous porous ceramics consolidated by propylene oxide

Silica sol, one of the most commonly used binders in the fabrication of fibrous porous ceramics, can diffuse as the solvent evaporates during the drying stage, leading to an uneven structure of ceramics. To prevent the diffusion of silica particles and prepare homogeneous mullite fibrous porous ceramics, propylene oxide (PO) was introduced into the fabricating procedures. The effects of solid content of silica sol and the molar ratio of PO /silica phase (PO/SiO2) on the microstructure and physical properties of mullite fibrous porous ceramics were also investigated. The results demonstrated that PO addition strongly consolidated the mullite fibrous skeleton and helped to obtain a homogenous property, because silica phase had been consolidated in situ around the fibers during the gelation stage. Furthermore, the mullite fibrous ceramics prepared with PO addition showed an even microstructure and a much better compressive strength (1.489 MPa), compared with the ones prepared without PO addition (0.868 MPa). Finally, the solid content of silica sol showed a very strong relevance to the properties of the ceramics: the compressive strength raised from 0.731 MPa to 1.715 MPa with the solid content of silica sols increasing from 9 wt% to 18 wt%; while the molar ratio of PO/SiO2 had little: the compressive strength was around 1.480 MPa, with the corresponding molar ratios of PO/SiO2 ranging from 0.43 to 1.72.

A Zn-MOF-Catalyzed Terpolymerization of Propylene Oxide, CO2, and β-butyrolactone

The terpolymerization of propylene oxide (PO), CO2, and a lactone is one of the prominent sustainable procedures for synthesizing thermoplastic materials at an industrial scale. Herein, the one-pot terpolymerization of PO, CO2, and β-butyrolactone (BBL) was achieved for the first time using a heterogeneous nano-sized catalyst: zinc glutarate (ZnGA-20). The reactivity of both PO and BBL increased with the CO2 pressure, and the polyester content of the terpolymer poly (carbonate-co-ester) could be tuned by controlling the infeed ratio of PO to BBL. When the polyester content increased, the thermal stability of the polymers increased, whereas the glass transition temperature (Tg) decreased.

Rigid linked dinuclear salph-co(III) catalyst for carbondioxide/epoxides copolymerization

Mononuclear and dinuclear salen-co(III) catalysts were designed for carbon dioxide (CO2) and propylene oxide (PO) copolymerization. The dinuclear system maintained its activity with a turn over frequency (TOF) of 406h−1 at [PO]/[Cat]=20,000. In contrast, the mononuclear catalyst system almost lost its activity with a TOF of 3h−1. The two cobalt centers in dinuclear structure may work synergistically due to the conjugated structure. This may contribute to the enhancement of the activity. The dinuclear catalyst system offered the highest molecular weight (Mn=200,000) among reported dinuclear catalysts heretofore. Polymerization mechanism for the dinuclear catalyst system was postulated based on the subtly designed experiments. Synergy effect with the positive help of cocatalyst was explored. To further enhanced the thermal property of poly(propylene carbonate) (PPC), poly(cyclohexene carbonate) (PCHC) was incorporated. The glass transformation temperature of the copolymer of PPC-PCHC could be adjusted by the feed ratio of PO and cyclohexene oxide (CHO).

Nitric Oxide-Releasing Amphiphilic Poly(amidoamine) (PAMAM) Dendrimers as Antibacterial Agents

A series of amphiphilic nitric oxide (NO)-releasing poly(amidoamine) (PAMAM) dendrimers with different exterior functionalities were synthesized by a ring-opening reaction between primary amines on the dendrimer and propylene oxide (PO), 1,2-epoxy-9-decene (ED), or a ratio of the two, followed by reaction with NO at 10 atm to produce N-diazeniumdiolate-modified scaffolds with a total storage of ~1 μmol/mg. The hydrophobicity of the exterior functionality was tuned by varying the ratio of PO and ED grafted onto the dendrimers. The bactericidal efficacy of these NO-releasing vehicles against established Gram-negative Pseudomonas aeruginosa biofilms was then evaluated as a function of dendrimer exterior hydrophobicity (i.e., ratio of PO/ED), size (i.e., generation), and NO release. Both the size and exterior functionalization of dendrimer proved important to a number of parameters including dendrimer-bacteria association, NO delivery efficiency, bacteria membrane disruption, migration within the biofilm, and toxicity to mammalian cells. Although enhanced bactericidal efficacy was observed for the hydrophobic chains (e.g., ED), toxicity to L929 mouse fibroblast cells was also noted at concentrations necessary to reduce bacterial viability by 5-logs (99.999% killing). The optimal PO to ED ratios for biofilm eradication with minimal toxicity against L929 mouse fibroblast cells were 7:3 and 5:5. The study presented herein demonstrated the importance of both dendrimer size and exterior properties in determining efficacy against established biofilms without compromising biocompatibility to mammalian cells.

The Effect of Propylene Oxide on Microstructure of Zirconia Monolithic Aerogel

Uncracked zirconia (ZrO2) monolithic aerogels were prepared using a sol–gel process accompanied by high temperature supercritical fluid drying technology. Moreover, the experimental results on microstructure of ZrO2 aerogels modified by PO (propylene oxide) were reported. As more PO added to the starting solution, pH rose and the gel time decreased. SEM and N2 adsorption–desorption curves showed that the particle With the molar ratio of PO to Zr increasing from 0 to 2.5, size and connectivity of network of ZrO2 aerogels increased, while average pore radius increased from 6.6 nm to 15.1 nm then decreased to 8.5nm and pore volume increased from 1.2 cc/g to 1.87 cc/g then decreased to 1.44 cc/g.

Polyester polyol synthesis by alternating copolymerization of propylene oxide with cyclic acid anhydrides by using double metal cyanide catalyst

Ring-opening copolymerizations of propylene oxide (PO) with cyclic acid anhydrides, succinic anhydride (SA), maleic anhydride (MA) and phthalic anhydride (PA) were carried out in the presence of a double metal cyanide (DMC) catalyst of molecular formula Zn2.3Cl1.0[Co(CN)6]1.0⋅2.0tBuOH⋅1.0H2O as a means of developing functional polyols bearing ester backbones. Uniform alternating copolymers are produced when [PO]/[anhydride] in the copolymer approaches unity. All resulting copolymers have moderate molecular weights (Mn = 2300–10,600) and a narrow polydispersity index (1.02–1.49). The apparent reactivity ratio of PO is 0.34, 0.28, and 0.26 for PO/SA, PO/MA, and PO/PA copolymerizations, respectively, assuming that the reactivity ratio of the anhydrides is zero. The DMC-catalyzed PO copolymerizations with anhydrides are an efficient way to produce polyester polyols, expanding the versatility of conventional polyols.

Ring‐opening copolymerization of maleic anhydride with propylene oxide by double‐metal cyanide

AbstractRing‐opening copolymerization of maleic anhydride (MA) with propylene oxide (PO) was successfully carried out by using double‐metal cyanide (DMC) based on Zn3[Co(CN)6]2. The characteristics of the copolymerization are presented and discussed in this article. The structure of the copolymer was characterized with IR and 1H‐NMR. Number‐average molecular weight (Mn) and molecular weight distribution (MWD) of the copolymer were measured by GPC. The results showed that DMC was a highly active catalyst for copolymerization of MA and PO, giving high yield at a low catalyst level of 80 mg/kg. The catalytic efficiency reached 10 kg polymer/g catalyst. Almost alternating copolymer was obtained when monomer charge molar ratio reached MA/PO ≥ 1. The copolymerization can be also carried out in many organic solvents; it was more favorable to be carried in polar solvents such as THF and acetone than in low‐polarity solvents such as diethyl ether and cyclohexane. The proper reaction temperature carried in the solvents was between 90 and 100 °C. The Mn was in the range of 2000–3000, and it was linear with the molar ratio of conversion monomer and DMC catalyst. The reactivity ratio of MA and PO in this reaction system was given by the extended Kelen–Tudos equation: η=[r1+(r2/α)]ξ−(r2/α) at some high monomer conversion. The value of reactivity ratio r1(MA) = 0 for MA cannot be polymerized itself by DMC catalyst, and r2(PO) = 0.286. The kinetics of the copolymerization was studied. The results indicated that the copolymerization rate is first order with respect to monomer concentration. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1788–1792, 2004

Ring‐opening polymerization of epichlorohydrin and its copolymerization with other alkylene oxides by quaternary catalyst system

AbstractAn effective quaternary catalyst consisting of trialkyl aluminum, phosphoric acid, electron donor, and water for ring‐opening polymerization of epichlorohydrin (ECH), as well as its copolymerization with ethylene oxide (EO), propylene oxide (PO), and allyl glycidyl ether (AGE) to obtain elastomers, were studied. We investigated the optimum composition for the quaternary catalyst; the character of the catalyst; the reactivity of the four alkylene oxides during homopolymerization and copolymerization; the behavior of ECH, EO, and PO during terpolymerization; and glass transition temperatures of the copolymer and terpolymers. The results showed that the nitrogen‐containing electron donors are suitable as the third component, whereas oxygen‐containing electron donors are not. Water as the fourth component can increase the molecular weight of the homopolymer and copolymers of ECH. According to the polymerizability of tetrahydrofuran with the quaternary catalyst and the reactivity ratios of the four alkylene oxides, the quaternary catalyst was assumed to be of a coordinated anionic type. The reactivity ratios for these four alkylene oxides were determined to be EO &gt; PO &gt; AGE &gt; ECH. They were verified by terpolymerization of ECH, EO, and PO. The glass transition temperature of the terpolymer exhibits a minimum value at nearly 3:1 molar ratio of PO to EO, when the molar ratio of ECH used is constant at the beginning of terpolymerization. © 2001 John Wiley &amp; Sons, Inc. J Appl Polym Sci 80: 2446–2454, 2001

Dimethylaminoethylated hydroxypropyl-chitosan: Preparation and application as polymeric ligand to form Rh6 cluster complexes for the reduction of benzaldehyde and nitrobenzene

Hydroxypropyl chitosan and its dimethylaminoethylated derivative were prepared in different conditions. Experimental results indicated that the degree of substitution (DS) of hydroxypropyl chitosan was strongly related to the molar ratio of propylene oxide to the glucosamine unit of chitosan, the used solvent, the reaction temperature and the amount of sodium hydroxide. Moreover, the obtained hydroxypropyl chitosan could be effectively dimethylaminoethylated by the reaction with dimethylaminoethyl chloride in the presence of NaH under DMAC solution. By the combination of dimethylaminoethylated hydroxypropyl chitosan and Rh 6 (CO) 16 , benzaldehyde and nitrobenzene could be converted into correspondingly reductive products in high yields under the WGSR condition.

Alkylation of 2-methoxynaphthalene with propylene oxide using titanium and zirconium containing molecular sieves

Titanium and zirconium containing molecular sieves are active catalysts for the alkylation of 2-methoxynaphthalene (2-MN) with propylene oxide (PO). Temperatures above 423 K are necessary in order to promote the alkylation reaction. A major competing reaction that deactivates the catalyst is the oligomerization of PO that provides for deposition of these oligomers on the catalyst surface. A high 2-MN to PO ratio as well as the addition of PO in a semi-batch mode of operation help minimize the oligomerization reaction. The main reaction products are an O-alkylated product ( I) and four C-alkylated products: 1-(2-methoxy-1-naphthyl)-2-propanol ( II), 2-(2-methoxy-1-naphthyl)propanol ( III), 1-(6-methoxy-2-naphthyl)-2-propanol ( IV) and 2-(6-methoxy-2-naphthyl)propanol ( V). The conversion of the limiting compound (PO) can be as high as 50% with selectivities towards the desired product V ranging from 12 to 20%. The ratio of 2,6- to 1,2-product is 1.6 for Ti-BEA, while Zr-BEA shows a value of 3.0. The shape-selective effect of the molecular sieve catalysts can be enhanced by passivation or poisoning of the outer surface of the catalyst by treatment with tetraethylorthosilicate (TEOS), tris[2-(diphenylphosphino)ethyl]-phosphine (TETRAPHOS-II), ethylenediaminetetraacetic acid (EDTA) or hydrogen peroxide (H 2O 2). For these cases, the 2,6- to 1,2-products ratios can reach values of up to 4. No leaching of Ti or Zr from the molecular sieve materials is observed.