No abstract

FAME of lard, beef tallow, and chicken fat were prepared by base-catalyzed transesterification for use as biodiesel fuels. Selected fuel properties of the neat fat-derived methyl esters (B100) were determined and found to meet ASTM specifications. The cold-flow properties, lubricity, and oxidative stability of the B100 fat-derived fuels also were measured. In general, the cold-flow properties of the fat-based fuels were less desirable than those of soy-based biodiesel, but the lubricity and oxidative stability of the fat-based biodiesels were comparable to or better than soy-based biodiesel. Nitrogen oxide (NO x ) emission tests also were conducted with the animal fat-derived esters and compared with soybean oil biodiesel as 20 vol% blends (B20) in petroleum diesel. The data indicated that the three animal fat-based B20 fuels had lower NO x emission levels (3.2-6.2%) than did the soy-based B20 fuel.Paper no. J11054 in JAOCS 82, 585-591 (August 2005).

Abstract:1 H NMR and 13 C NMR spectrometry (1-dimensional and 2-dimensional) have been used to assign chemical resonances and determine the degrees of branching for polyesters synthesized by the Lewis acid (dibutyltin(IV)oxide)-catalyzed polycondensation of glycerol with either succinic acid (n (aliphatic chain length) = 2), glutaric acid (n = 3) or azelaic acid (n = 7) in quasi-melt solutions with toluene. When 1:1 and 2:1 (diacid:glycerol) molar ratios were used, it was found that the glutaric acid-derived polymers gave the highest degree of polymer branching (31.2%, 85.6%, respectively) after the 24 h reaction period followed by the succinic acid-derived polymers (39.4%, 41.9%, respectively) and the azelaic acid-derived polymers (9.9%, 13.9%, respectively). Reactions performed at reflux for 24 h resulted in a 70.8% and 56.7% decrease in degree of branching for succinic acid and glutaric acid-derived polyesters, respectively. There is no indication that degree of branching is significantly affected by the presence or absence of solvent according to the results obtained in this research.

Novel oligomeric prepolymers were synthesized by acid-catalyzed condensation of glycerol with iminodiacetic, azelaic, or succinic acid. The prepolymers were obtained, on average, in 62% yield and were characterized by 13 C NMR, 1 H NMR, matrix-assisted laser desorption ionization-time of flightmass spectrometry, and gel permeation chromatography. The synthesized oligomers had an average M.W. of 1543 Daltons (average polydispersity (PD) = 1.34, average degree of polymerization (DOP) = 5.5). Hyperbranching was evident in the oligomers produced when using azelaic acid and succinic acid as co-monomers with glycerol, whereas the reaction between iminodiacetic acid and glycerol resulted in linear products bearing cyclic urethane structures.

Examples of monomeric glycerol-derived hyperbranched polyesters produced in a nonpolar solvent system are reported here. The polymers were made by the Lewis acid [dibutyltin(IV) oxide]-catalyzed polycondensation of glycerol with either succinic acid [n (aliphatic chain length) = 2], glutaric acid (n = 3), or azelaic acid (n = 7) in toluene. Poly(glycerol-diacid)s were recovered in yields as low as 65% and as high as 95%. The polyesters were characterized by gas chromatography to determine the extent of reaction and by gel permeation chromatography to determine molecular weight, polydispersity index, and degree of polymerization. None of the conditions explored gave 100% conversion but products could be recovered in greater than 97.8% purity. Gelation and low conversion were observed, respectively, for 24-and 10-h polyesterifications of glutaric acid and glycerol (2:1 molar ratio) performed at 155°C when the standard (neat) synthetic protocol was employed. Gelation was avoided and conversion improved when esterifications were performed in quasi-melt solutions with toluene. The optimal reaction conditions to produce polymers with high conversion and high molecular weight before the onset of gelation were observed for 24-h esterifications in toluene at 155°C (2:1 molar ratio of glutaric acid/glycerol) and 135°C (1:1 molar ratio of reactants). Expanding on the success of those findings, it was determined that gelation could be avoided for each of the three diacids studied. When all other conditions were held constant, in the absence of gelation, degree of polymerization increased with decreasing aliphatic chain length of the diacid.

Hydrogels and organogels are polymer networks that can absorb large amounts of water and organic solvent, respectively. In this study, solvent absorption into the matrices of poly(glutaric acid‐glycerol) hydrogel and organogel films amended with or without either iminodiacetic acid, sugarcane bagasse, pectin, corn fiber gum, or microcrystalline cellulose has been evaluated. Most of the starting materials used in this study, such as glycerol and the plant wall polysaccharides, are by‐products of biofuel production. Finding uses for them would further biofuel initiatives worldwide. To that end, experimental results showed that water absorption increased when using polymer films composed of additional glycerol or plant cell wall polysaccharides. The amount of solvent absorbed into the control film increased when incubated in pH 10 buffer solutions but decreased when incubated in pH 4 buffer solutions and NaCl solutions when compared with absorption of water. Incubating the polymers in solvent at elevated temperatures increased the absorption rate. It was determined that the combined effects of pKa and polarity can be used to predict solvent absorption. Dimethylsulfoxide (DMSO) could be selectively extracted from or desorbed into films from other solvents. Erosion of the polymer films in DMSO ranged from 1.9 (±0.2) to 34.7 (±3.4)%. In water, erosion ranged from 6.3 (±3.2) to 32.7 (±3.2)%. The polymer films resorbed 3.3‐ and 2.3‐fold more DMSO and water, respectively, when compared with the original amount of absorbed solvent. These materials are potentially good candidates for agricultural and medicinal applications because their ability to absorb, desorb, and erode can be tuned. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

The Lewis acid, titanium (IV) butoxide [15% (w/w; catalyst/reactants)], was used to catalyze the condensation of 0.05 mol glycerol with 0.10 mol of succinic acid, glutaric acid, and azelaic acid to produce oligomers. The reactions were refluxed in dilute solutions of dimethylsulfoxide (DMSO) or dimethylformamide (DMF) for 24 h. The oligomers were obtained, on average, in 84% yield and were soluble in polar organic solvents. Analysis by gel permeation chromatography determined that the oligomers had a number of average molecular weights (M n ) ranging from 2,118 to 3,245 g/mol, with degrees of polymerization (DOP) ranging from 12.2 to 13.4 repeat units. The oligomers had low polydispersities (M w /M n ) that averaged &1.33. Degrees of branching were determined by one-dimensional and two-dimensional 1 H NMR and 13 C NMR and varied from 25 to 80%. Like M n and the DOP values, the degrees of branching were dependent on the aliphatic chain length of the diacid. MALDI-TOF mass spectrometry was used to detect ionated species that were unique to branched molecules. It was also used to validate NMR studies that suggested that some diacids were terminated with dimethylamine, generated from the hydrolysis of DMF, by as much as 36%.

Monoglycerides (MGs) have been incorporated into the matrix of poly(glycerol-co-glutaric acid) films to investigate their effect on the thermal, mechanical, and solvent absorption properties of the resultant films. Solvent absorption studies revealed that poly(glycerol-co-glutaric acid-co-MG) films were able to absorb and resorb solvents better than poly(glycerol-co-glutaric acid) films, albeit they had higher erosion levels. Thermogravimetric analysis showed that the incorporated MGs did not affect the thermal stability of the glycerol-based films. The MG-incorporated films were observed to be much softer than the poly(glycerol-co-glycerol) films which was further proven by a 39-fold reduction in Young's Modulus and 17-fold reduction in fracture energy when compared to the poly(glycerol-co-glycerol). Mechanical property studies also revealed that the incorporation of MGs increased the elongation % and reduced the tensile strength of poly(glycerol-co-glutaric acid) films. Correlation analysis revealed a strong linear relationship between Young's Modulus and fracture energy (R 2 5 0.9962), and between Young's Modulus and tensile strength (R 2 5 0.9972). Our study proved that MGs can be successfully incorporated in the polymer matrix of poly(glycerol-co-glutaric acid) films to produce softer films with increased elongation and increased solvent absorption capacity.