Propanediol Research Articles

Synthesis and characterization of cross-linked poly(esterurethane)s for elastomeric bearings

Summary — Cross-linked poly(esterurethane) elastomers (PEURs) have been synthesized in a two-step synthesis. In the first step poly(ethylene adipate) diol was reacted with 4,4’-diphenylmethane diisocyanate, then the obtained prepolymers were chain extended with bifunctional precursor (1,3-propane diol or 1,5-pentane diol) chains and a trifunctional cross-linker (glycerine) at stoichiometric ratios, resulting in a series of cross-linked products with various hard segment (HS) of various structure and content. Their thermal and mechanical properties were determined. Due to phase separation and cross-linked hard segments, propane diol based polyurethane exhibited high mechanical properties. The replacement of propane diol with pentane diol had a negative effect on these mechanical properties. The described cross-linked PEURs possessed strain/shape recovery properties.

Theoretical study on the effect of intramolecular hydrogen bonding on OH stretching overtone decay lifetime of ethylene glycol, 1,3-propanediol, and 1,4-butanediol

It is well known that the existence of hydrogen bonds causes the vibrational spectra for the donor OH bond to broaden. Most times this broadening is attributed to inhomogeneous contributions, however in this paper, we studied the homogeneous contribution coming from the decay lifetime of the OH stretching excitation. Alkane diol, which possesses an OH(b)OH(f) (b and f stand for hydrogen bonded and free, respectively) intramolecular hydrogen bond, provides us with a controllable molecule to systematically study the effect of intramolecular hydrogen bond on the decay rate of the OH vibrational excitation. In the present study we performed local mode vibrational calculation of gas phase ethylene glycol (EG), 1-3 propanediol (PD), and 1-4 butanediol (BD) using the potential energy curves calculated using B3LYP/6-31+G(d,p), MPW1PW91/6-311+G(2d,p), M06-2X/6-311+G(2df,2p), and MP2/6-311++G(3df,3pd) methods. In addition, we studied the dynamics of OH overtone excited state (Δv(OH) = 3, 4) for the two most stable conformers of the aforementioned diols using the direct dynamics calculation employing the B3LYP/6-31+G(d,p) method. From the trajectory simulations we showed that the decay lifetime from the donor OH(b) excitation decreases while that from the acceptor OH(f) excitation increases as we increase the intramolecular hydrogen bond strength in going from EG, PD, to BD. These results are consistent with the gas phase experimental results of Kjaergaard et al. where the OH(b) peaks, which are sharp for EG disappear for BD. From the detailed analysis on the trajectories, we observed that the decrease in decay lifetime for the OH(b) bond excitation originates from the increase in the energy flow to the OH(b)O torsion/bend motion, while the increase in lifetime for OH(f) bond is due to the fixing of the OH(f) geometry by accepting a donor hydrogen. Furthermore, by plotting the calculated red shift versus the decay lifetime we obtained the following relationship T(decay)(fs) = 343176(Δω(cm(-1)))(-1.36).

105 CRYOPRESERVATION OF VENDA COCK SPERMATOZOA: EFFECT OF CRYOPROTECTANT FOLLOWING ANALYSIS BY COMPUTER-ASSISTED SPERM ANALYSIS

The choice of ideal permeable cryoprotectant for cock semen equilibration and freezing is critical. The aim of this study was to compare three different cryoprotectants [dimethyl sulfoxide (DMSO), ethylene glycol (EG), and propanediol (PND)] following cryopreservation. The abdominal massaging technique was used for semen collection from 5 Venda cocks. Individual ejaculates were diluted with modified Kobidil+ (mK+) extender (fraction A) at a ratio of 1:2 and equilibrated for 2 h at 5°C. Semen samples of 5 μL were taken at 0, 60, and 120 min and evaluated by CASA for spermatozoa motility parameters (rapid, medium slow, static, NPM and PM) and velocity. Semen was further diluted at 1:1 volume ratio with mK+ supplemented with 8% DMSO, EG and PND (fraction B), and equilibrated for additional 2h at 5°C and evaluated at 60 and 120 min for motility and velocity. Cooled semen were then transferred into 0.25-mL straws and placed into a programmable freezer. The temperature of the chamber was decreased in a stepwise manner, from 5°C to -20°C, at the rate of 1°C/min until it reached the target temperature. The straws were exposed to liquid nitrogen (LN2) vapor and then plunged into LN2 (-196°C). The semen straws were stored into LN2 tank at -196°C. After 3 months of storage, semen straws were thawed at 5°C and evaluated by CASA for spermatozoa motility and velocity. Data were analyzed by ANOVA. There were no significance differences between DMSO and EG regarding the survival and motility rate of frozen/thawed semen; however, these parameters were lower compared with the fresh semen. The PND was not a suitable cryoprotectant to cryopreserve Venda spermatozoa. In conclusion, ethylene glycol was found to be a suitable cryoprotectant to cryopreserve spermatozoa of South African Venda cocks. Department of Agriculture Forestry and Fisheries, NRF,ARC, Department of Science & Technology.

Study on the influence of teos–diol molar ratio on their chemical interaction during the gelation process

Hybrid organic–inorganic materials, silica–diol, were synthesized by the sol–gel process from mixtures of tetraethylorthosilicate (TEOS) and diols: ethylene glycol (HO–CH2–CH2–OH) and 1,3 propane diol (HO–CH2–CH2–CH2–OH), in acid catalysis. The gels have been synthesized for a molar ratio H2O:TEOS = 4:1 and different molar ratios diol/TEOS: 0.25; 0.5; 0.75; 1.0; 1.25 and 1.5. The resulting gels were studied by thermal analysis and FT-IR spectroscopy, in order to evidence the interaction of diols with silica matrix. Thermal analysis indicated that the condensation degree increases with the molar ratio diol/TEOS until a certain value. The thermal decomposition of the organic chains bonded within the silica network in the temperature range 250–320 °C, leaded to a silica matrix with modified morphology. The adsorption–desorption isotherms type is different for the samples with and without diol. Thus, the specific surface areas have values 200 m2/g for the samples with diols, depending on the annealing temperature.

N,N‐diethyl dithiocarbamato group induced photografting of methyl methacrylate onto polyurethane

AbstractThe N,N‐diethyl dithiocarbamato group present in a variety of compounds acts as an initiator in the photopolymerization processes. The photolability of this group is due to the cleavage of the CS bond by UV irradiation. N,N‐Diethyl dithiocarbamato‐(1,2)‐propane diol with a pendent N,N‐diethyl dithiocarbamato group was prepared from 3‐chloro‐(1,2)‐propane diol and sodium diethyl dithiocarbamate. A polyurethane macrophotoinitiator was then synthesized by a two‐step process, where N,N‐diethyl dithiocarbamato‐(1,2)‐propane diol was used as the chain extender. Other components used included 4,4′‐diphenylmethane diisocyanate and poly(propylene glycol) (molecular weight = 1000). The polyurethane thus synthesized had pendent N,N‐diethyl dithiocarbamato groups. This polyurethane macrophotoinitiator was then used to polymerize methyl methacrylate in a photochemical reactor (Compact‐LP‐MP 88) at 254 nm. The resulting graft copolymer, polyurethane‐g‐poly(methyl methacrylate), was freed from the homopolymer by a standard procedure. The graft copolymer was characterized by Fourier transform infrared spectroscopy, 1H‐NMR spectroscopy, thermogravimetric analysis, differential scanning calorimetry, solution viscometry, and scanning electron microscopy. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

71 COMPARISON OF CRYOPROTECTANTS ON CRYOPRESERVATION OF VENDA COCK SPERMATOZOA

Improving the cryopreservation technique for indigenous fowl semen may contribute to the development of cryogene banks in South Africa. The goal was to identify a cryoprotectant among dimethyl sulfoxide (DMSO), ethylene glycol (EG), and propanediol (PND) that is compatible with survival after freezing of Venda cock spermatozoa. Six Venda cocks were used for semen collection. The abdominal massaging technique was applied for semen collection from cocks. Individual ejaculates were diluted with modified Kobidil+ (mK+) extender (extender A) at ratio of 1:2 (v/v) before freezing, and equilibrated for 2 h. Semen was diluted again at a ratio of 1:1 (v/v) with mK+ plus 8% DMSO, EG, and PND (extender B) and equilibrated for 2 h at 5°C. Semen were then transferred into 0.25-mL plastic straws and placed into a programmable freezer (Planer Kryosave). The temperature of the chamber was decreased in a stepwise manner, from 5°C at a rate of 1°C min–1 until it reached the target temperature of –20°C. Finally, the straws were exposed to liquid nitrogen (LN2) vapor and plunged into LN2 (–196°C). The semen straws were stored in an LN2 tank at –196°C. After 1 week, frozen semen straws were thawed at 5°C for evaluation of spermatozoa survivability and motility rate at 0, 30, 60, and 90 min, using contrast microscopy (20× magnification). Data were analyzed by ANOVA. Spermatozoa live and motility rates were greater before freezing (Table 1) in all groups. There was no significance difference between DMSO and EG with regard to live and motility rates. However, the lowest rates of live and motility spermatozoa were recorded in the PND group. In conclusion, this study demonstrated that the cryopreservation process reduces sperm quality and propanediol was not suitable for cryopreserving Venda cock spermatozoa. Table 1.Comparison of three CPA on cryopreservation of Venda cock semen This study was funded by the South African National Department of Agriculture, ARC, DST-PDP (RT19000), and National Research Foundation (NRF, Grant. no. RT21 and 24000).

Glass transition behavior of the vitrification solutions containing propanediol, dimethyl sulfoxide and polyvinyl alcohol

Knowledge of the glass transition behavior of vitrification solutions is important for research and planning of the cryopreservation of biological materials by vitrification. This brief communication shows the analysis for the glass transition and glass stability of the multi-component vitrification solutions containing propanediol (PE), dimethyl sulfoxide (Me2SO) and polyvinyl alcohol (PVA) by using differential scanning calorimetry (DSC) during the cooling and subsequent warming between 25 and −150°C. The glass formation of the solutions was enhanced by introduction of PVA. Partial glass formed during cooling and the fractions of free water in the partial glass matrix increased with the increasing of PVA concentration, which caused slight decline of glass transition temperature, Tg. Exothermic peaks of devitrification were delayed and broadened, which may result from the inhibition of ice nucleation or recrystallization of PVA.

The dielectric relaxation of binary mixtures of propanediamine and propanediol

Dielectric spectra of binary mixtures of propanediamine (PDA) and propanediol (PDO) are measured by TDR (time domain reflectometry). The KWW (Kohlrausch–Williams–Watts) function is used to obtain relaxation parameters. The observed relaxation time has a maximum at around 0.7 mole fraction of PDO. The concentration dependence of the relaxation time suggests that the intermolecular interaction between PDA and PDO is stronger than that of pure amines and of pure alcohols.

Cryoprotectant delivery and removal from murine insulinomas at vitrification-relevant concentrations

Development of optimal cryopreservation protocols requires delivery and removal of cryoprotective agents (CPAs) in such a way that negative osmotic and cytotoxic effects on cells are minimized. This is especially true for vitrification, where high CPA concentrations are employed. In this study, we report on the determination of cell membrane permeability parameters for water ( L p) and solute ( P s), and on the design and experimental verification of CPA addition and removal protocols at vitrification-relevant concentrations for a murine insulinoma cell line, βTC-tet cells. Using membrane permeability values and osmotic tolerance limits, mathematical modeling and computer simulations were used to design CPA addition and removal protocols at high concentrations. The cytotoxic effects of CPAs were also evaluated. Cells were able to tolerate the addition and removal of 2.5 M dimethyl sulfoxide (DMSO) and 2.5 M 1,2 propanediol (PD) in single steps, but required multi-step addition and removal with 3.0 M DMSO, 3.0 M PD, and a vitrification-relevant concentration of 3.0 M DMSO + 3.0 M PD. Cytotoxicity studies revealed that βTC-tet cells were able to tolerate the presence of single component 6.0 M DMSO and 6.0 M PD and to a lesser extent 3.0 M DMSO + 3.0 M PD. These results determine the time and concentration domain of CPA exposure that cells can tolerate and are essential for designing cryopreservation protocols for free cells as well as cells in engineered tissues.

The interaction between TEOS and some polyols

Hybrid organic-inorganic materials, silica – polyols (ethylene-glycol – EG; 1,2 propane diol – 1,2PG; 1,3 propane diol – 1,3PG and glycerol – GL), were prepared by a sol-gel process starting from tetraethylorthosilicate (TEOS) and polyols, in acid catalysis. The resulting materials were studied by thermal analysis (in air and nitrogen), FTIR and solid state 29Si-NMR spectroscopy. These techniques evidenced the presence of polyols in the silica matrix both hydrogen bounded and chemically bounded in the silica network. The thermal analysis proves to be the most appropriate technique to evidence the organic chains linked in the matrix network and to follow the thermal evolution of the gels to the SiO2 matrix.

Formation of uniform colloidal ceria in polyol

Well-dispersed uniform spheres of crystalline CeO 2 were prepared by calcining precursor particles obtained by heating cerium(III) acetate in 1,2 propane diol (propylene glycol, PG) at the boiling point of the polyol (∼187 °C) for several hours. The first precipitated amorphous spherical particles consist of a complex mixture of ceria, ceria hydrate, cerium hydroxide, cerium glycolate complex and residual PG. To convert these precursors to pure CeO 2, the solids were calcined at 500 °C in air at a slow heating rate (≤0.1 °C/min). The purification of the precursor particles depended strongly on the solvent used. By washing with water, much of the organic material was leached out resulting in smaller spheres, while rinsing with methanol showed little effect. The TGA, FTIR, XRD, EDX analyses of the different purified particles revealed the stages in the formation of the final pure well-defined CeO 2 powder.

A kinetic investigation of polyurethane polymerization for reactive extrusion purposes

AbstractThe effects of the reaction conditions on the kinetics of two different polyurethane systems were investigated. To do so, three different kinetic methods were compared: adiabatic temperature rise (ATR), measurement kneader, and high‐temperature measurements. For the first polyurethane system, consisting of 4,4‐diphenylmethane diisocyanate (4,4‐MDI), butane diol, and a polyester polyol, the reaction conditions did not seem to matter; a kinetically controlled reaction was implicated for all reaction conditions. The reaction was second order in isocyanate concentration and 0.5th order in catalyst concentration and had an activation energy of 52 kJ/mol. The second polyurethane system consisted of a mixture of 2,4‐diphenylmethane diisocyanate and 4,4‐MDI, methyl propane diol, and a polyester polyol. For this system, each of the three measurement methods showed different behavior. Only at a low catalyst concentration did the ATR experiments show catalyst dependence; at higher catalyst levels and for the other two measurement methods, no catalyst dependence was present. Furthermore, the ATR experiments proceeded much faster. Presumably, for this system, the rapid diffusion interfacial of the species present was hindered by the presence of bulky oligomer molecules. The result was a diffusion limitation reaction at low conversions and an inhomogeneous distribution of species at higher conversions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 370–382, 2006

Effect of the reaction conditions on the photopolymerization of methyl methacrylate by diethyl dithiocarbamato‐(1,2)‐propane diol

AbstractThe photopolymerization of methyl methacrylate (MMA) through the use of diethyl dithiocarbamato‐(1,2)‐propane diol (DCPD) was studied. The photoinitiator was synthesized from 3‐chloro‐1,2‐propane diol and sodium diethyl dithiocarbamate in a solvent mixture of acetone and anhydrous ethanol. The photopolymerization was carried out in a Heber multilamp photochemical reactor (COMPACT‐LP‐MP88) (Heber Scientific, Chennai, India) at 254 nm. The effects of the reaction conditions on the polymerization of MMA were studied. The conversion and molecular weight increased with an increase in the monomer concentration and reaction time. However, for the DCPD‐to‐MMA molar ratio, a critical value was found for maximum conversion. The results suggested the living radical nature of the photoinitiator, which was further investigated by the preparation of a block copolymer with styrene. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2320–2328, 2005

New route to propanediol

New route to propanediol

Optimization of yield in kinetically controlled synthesis of ampicillin with immobilized penicillin acylase in organic media.

Immobilized penicillin acylase is a moderately priced versatile enzyme, that is able to catalyze the synthesis of derived penicillins and cephalosporins from the corresponding beta-lactam nuclei and proper side-chain precursors. Kinetically controlled synthesis is a better strategy when product yield is a key issue. Yield should increase at reduced water activity by depressing the competing hydrolytic reactions in favor of synthesis; therefore, organic cosolvents can be a suitable reaction media for synthesis. Using response surface methodology and product yield as objective function, temperature and pH were optimized in the kinetically controlled synthesis of ampicillin using previously screened cosolvents and reaction conditions. Optimum pH was 6.0 for ethylene glycol (EG) and glycerol (GL) and 6.6 for 1-2 propanediol (PD); optimum temperature was 30 degrees C for GL and for EG and PD was in the lower extreme of the range studied, optimum lying below 26 degrees C. Maximum molar yields predicted by the model were 58,51, and 46% for EG, GL, and PD, respectively, which were experimentally validated. Highest yield in aqueous buffer was always <40%. Molar yields about 60% compare favorably with values reported for the kinetically and thermodynamically controlled synthesis of ampicillin and other derived penicillins.

Proteasome inhibitors and immunosuppressive drugs promote the cleavage of eIF4GI and eIF4GII by caspase-8-independent mechanisms in Jurkat T cell lines

Previously, we have shown that translation eukaryotic initiation factor (eIF) 4GI is cleaved during anti-Fas-mediated apoptosis. Here, we have investigated the effects of the proteasome inhibitors, MG132 and lactacystin, and the immunosuppressants, 2-amino-2[2-(4-octylphenyl)ethyl]-1,3,propane diol (FTY720) and cyclosporin A, on the integrity of eIF4GI and eIF4GII in T cells. Using wild-type Jurkat T cells, we show that the proteasome inhibitors MG132 and lactacystin promote the cleavage of eIF4G, activate caspase-8 and caspase-3-like activities and decrease cell viability. Furthermore, MG132 also promotes the cleavage of eIF4G and the activation of caspase-3-like activity in a caspase-8-deficient Jurkat cell line which is resistant to anti-Fas-mediated apoptosis. Using specific anti-peptide antisera, we show that both eIF4GI and eIF4GII are cleaved in either cell line in response to MG132 and lactacystin. In response to such treatments, we demonstrate that the fragments of eIF4GI generated include those previously observed with anti-Fas antiserum together with a novel product which lacks the ability to interact with eIF4E. In contrast, cells treated with the immunosuppressants FTY720 and cyclosporin A appear to contain only the novel cleavage fragment of eIF4GI and to lack those characteristic of cells treated with anti-Fas antiserum. These data suggest that caspase-8 activation is not required for apoptosis and eIF4G cleavage mediated by proteasome inhibitors and immunosuppressants in human T cells.

Chlorometabolite production by the ecologically important white rot fungus Bjerkandera adusta

Two strains of the basidiomycete, Bjerkandera adusta (DAOM 215869 and BOS55) produce in static liquid culture, phenyl, veratryl, anisyl and chloroanisyl metabolites (CAM's) (alcohols, acids and aldehydes) as well as a series of compounds not previously known to be produced by Bjerkandera species: 1-phenyl, 1-anisyl, 1-(3-chloro-4-methoxy) and 1-(3,5-dichloro-4-methoxy) propan-1,2-diols, predominantly as erythro diastereomers with 1 R, 2 S absolute configurations. 1-Anisyl-propan-1,2-diol and 1-(3,5-dichloro-4-methoxy)-propan-1,2-diol are new metabolites for which the names Bjerkanderol A and B, respectively, are proposed. Experiments with static liquid cultures supplied with 13 C 6 - and 13 C 9 -L-phenylalanine showed that all identified aromatic compounds (with the exception of phenol) can be derived from L-phenylalanine. For the aryl propane diols, the 13 C label appeared only in the phenyl ring and the benzylic carbon, suggesting a stereoselective re-synthesis from a C 7 and a C 2-unit, likely aromatic aldehyde and decarboxylated pyruvate, respectively. Other compounds newly discovered to be derived from phenylalanine by this white rot fungus include phenylacetaldehyde and phenylpyruvic, phenylacetic, phenyllactic, mandelic and phenyl glyoxylic (benzoyl formic) acids. For both strains, cultures supplied with Na 37Cl showed incorporation of 37 Cl in all identified chlorometabolites. Veratryl alcohol and the CAM alcohols, which occur in both strains and can be derived from L-phenylalanine (all 13 C -labelled), have reported important physiological functions in this white rot fungus. Possible mechanisms for their formation through the newly discovered compounds are discussed.

Wearable corn

A key ingredient in the manufacturing of plastics, previously only produced from petroleum, can now be made from corn. The development comes from Dupont and Tate & Lyle (Decatur, IL, USA). From a fermentation process of corn sugar, scientists can extract the chemical, 1,3,propanediol (PDO), which acts as a biocatalyst in polymer production. The polymer, commercially known as Sorona, can be spun into polyester-like textiles suitable for clothing. To date, DuPont has one manufacturing plant in the USA that is capable of using the corn-derived PDO. According to Ellen J. Kullman (DuPont), the product, ‘offers solid proof that biotechnology can and will deliver benefits in a wide variety of areas.’ (PR Presswire, 1 May 2001). TS

Purification and characterization of the 1-3-propanediol dehydrogenase of Clostridium butyricum E5.

1-3 PPD dehydrogenase (EC 1.1.1.202) was purified to homogeneity from Clostridium butyricum E5 grown anaerobically on glycerol in continuous culture. The native enzyme was estimated by gel filtration to have a molecular weight of 384 200 +/- 31 100 Da; it is predicted to exist as an octamer or a decamer of identical molecular weight subunits. When tested as a dehydrogenase, the enzyme was most active with 1-3 propane diol. In the physiological direction, 3-hydroxypropionaldehyde was the preferred substrate. The apparent K(m) values of the enzyme for 3-hydroxypropionaldehyde and NADH were 0.17 mM and 0.06 mM, respectively. The enzyme requires only Mn(2+) for full activity. The enzyme was found to have properties similar to those reported for Klebsellia pneumoniae, Citrobacter freundii, and Clostridium pasteurianum.

Effect of 1-γlinolenyl-3-eicosapentaenoyl propane diol on the growth of human pancreatic carcinoma in vitro and in vivo

Essential fatty acids such as gammalinolenic (GLA) and eicosapentaenoic (EPA) acids have been proposed as anticancer drugs. The aim of this study was to test the effect of a lipid emulsion containing both GLA and EPA in a novel chemical formulation of 1-γlinolenyl-3-eicosapentaenoyl propane diol on the growth of human pancreatic carcinoma in vitro and in nude mice. This compound had a dose-dependent growth-inhibitory effect on human pancreatic cancer cell lines MIA PaCa-2 and Panc-1 in vitro. The concentration necessary for 50% growth inhibition was 25 μmol/l for MIA PaCa-2 and 68 μmol/l for Panc-1 (95% CI 20–29 and 59-77 μmol/l respectively). Nude mice bearing subcutaneous pancreatic tumours produced with the MIA PaCa-2 cell line were treated with the maximum tolerated dose (6.75 mg GLA and 7.3 mg EPA per g of body weight) administered over 10 days by daily intravenous (i.v.) bolus injections. No antitumour effect or major alteration in tumour lipid fatty acid composition was seen in comparison with control animals. Concurrent treatment with parenteral iron (iron saccharate, 5 μg/gram body weight daily) did not make a significant difference. Further improvements in fatty acid delivery mechanisms are necessary before they can become useful anticancer agents.