Dicarboxylic Acid Dimethyl Ester Research Articles

Direct catalytic conversion of bagasse fibers to furan building blocks in organic and ionic solvents

The applications of lignocellulosic wastes to produce a wide variety of products, including biochemicals, biomaterials, and biofuels, can be an effective solution for utilizing these valuable waste materials. In this study, the production of furan building blocks from bagasse fibers was investigated by treating unbleached fibers with NMMO, [Bmim]Cl, and TMAH at different temperatures using AlCl3 and CrCl2 as the catalysts. The resulted liquors were extracted with CH2Cl2 to obtain furan rich fraction. Analysis of extracted fractions with GC/MS indicates the production of various furanic compounds due to catalytic solvolysis with different solvents at elevated temperatures. 2(3H)-Furanone and 2-methyl-THF were the main products of catalytic treatment of bagasse fibers with NMMO. Treatment by [Bmim]Cl resulted in 2,5-dihydro furanone as the dominant product at elevated temperatures. Furan carboxylic acid methyl ester and 2,5-furan dicarboxylic acid dimethyl ester were the main TMAH reaction products with unbleached fibers. The results indicate that the type of solvent affects the solvolysis rate and dehydration of cellulose to furanic compounds. Moreover, increasing the temperature led to an increase in the formation of the furanic compounds.Graphical abstract

Tung oil based plasticizer and auxiliary stabilizer for poly(vinyl chloride)

A tung oil derived epoxidized dicarboxylic acid dimethyl ester (epoxidized-C21-DAE), was synthesized through transesterification, a Diels-Alder reaction, and epoxidation. The chemical structure of the epoxidized-C21-DAE was confirmed using Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H NMR) and carbon-13 nuclear magnetic resonance (13C NMR). The thermal and migration stabilities and the mechanical properties of PVC samples were investigated using discoloration, tensile, exudation, volatility, and extraction tests as well as thermal gravity analysis (TGA), TGA–FTIR analysis, and dynamic mechanical analysis (DMA). The petroleum-based plasticizer, dioctyl terephthalate (DOTP), and the biobased plasticizer, epoxidized fatty acid methyl ester (EFAME), were chosen as controls and their properties compared with epoxidized-C21-DAE. The application of epoxidized C21-DAE as a biobased, primary plasticizer for poly(vinyl chloride) significantly improved PVC thermal stability over that of DOTP and EFAME. The mechanical properties of this type of PVC were superior to those of DOTP. In addition, the migration and volatility stabilities of epoxidized-C21-DAE were much better than EFAME. Epoxidized-C21-DAE could, therefore, be fully substituted for commercial DOTP or EFAME. Tung oil derived epoxidized-C21-DAE has good potential as a primary PVC plasticizer.

Rhodium‐catalysed cyclisation by addition of unsaturated 1,4‐dicarbonyl compounds to oleic acid methyl ester

The Rh‐catalysis allows the one‐step synthesis of Diels–Alder‐like cycloadducts from mono‐unsaturated fatty acid and 1,4‐dicarbonyl components. In this article we report on the addition of maleic acid‐, fumaric acid‐ and acetylene dicarboxylic acid dimethyl ester to oleic acid methyl ester. In previous studies, Rh(OAc)2 showed the highest selectivity of the investigated catalysts towards the 3,6‐disubstituted‐1,2,3,6‐tetrahydro‐phthalic acid derivatives (THPA) for the addition of maleic anhydride to oleic acid. Thus, it was also used in this study. The relative configurations of the final products were identified by comparison with the Diels–Alder products, resulting from conjugated linoleic acid methylester (CLAMe) and the mentioned 1,4‐dicarbonyl compounds.Practical applications: The Rh‐catalysis is an appropriate method to synthesise Diels–Alder‐like cycloadducts from mono‐unsaturated fatty acids derivatives and 1,4‐dicarbonyl compounds in a one‐step process. The resulting products are considered to be used as detergents, corrosion inhibitors, plasticiser or new monomeric building blocks, e.g. for polycondensation processes. The obtained polyesters can be used for several applications, e.g. for coatings or adhesives, and lead to new products with promising properties.Diels–Alder‐like cycloadducts can be obtained in a one‐pot reaction from mono‐unsaturated fatty acids and 1,4‐dicarbonyl compounds using Rh‐catalysts. In contrast to common Diels–Alder reactions, a conjugated diene is not mandatory as educt, but will be generated in situ from the mono‐unsaturated fatty acid compound. The configurations of the resulting cyclocadducts are determined by NMR‐measurements.

Chemical Characterization of Territorial Marking Fluid of Male Bengal Tiger, Panthera tigris

The territorial marking fluid of the male Bengal tiger, Panthera tigris, consists of a mixture of urine and a small quantity of lipid material that may act as a controlled-release carrier for the volatile constituents of the fluid. Using gas chromatography and gas chromatography-mass spectrometry, 98 volatile compounds and elemental sulfur were identified in the marking fluid. Another 16 volatiles were tentatively identified. The majority of these compounds were alkanols, alkanals, 2-alkanones, branched and unbranched alkanoic acids, dimethyl esters of dicarboxylic acids, gamma- and delta-lactones, and compounds containing nitrogen or sulfur. Several samples of the marking fluid contained pure (R)-3-methyl-2-octanone, (R)-3-methyl-2-nonanone, and (R)-3-methyl-2-decanone, but these ketones were partly or completely racemized in other samples. The gamma-lactone (S)-(+)-(Z)-6-dodecen-4-olide and the C(8) to C(16) saturated (R)-gamma-lactones and (S)-delta-lactones were present in high enantiomeric purities. The chiral carboxylic acids, 2-methylnonanoic acid, 2-methyldecanoic acid, 2-methylundecanoic acid, and 2-ethylhexanoic acid were racemates. Cadaverine, putrescine, and 2-acetylpyrroline, previously reported as constituents of tiger urine, were not detected. The dominant contribution of some ketones, fatty acids, and lactones to the composition of the headspace of the marking fluid suggests that these compounds may be important constituents of the pheromone. Although it constitutes only a small proportion, the lipid fraction of the fluid contained larger quantities of the volatile organic compounds than the aqueous fraction (urine). The lipid derives its role as controlled-release carrier of the chemical message left by the tiger, from its affinity for the volatiles of the marking fluid. Six proteins with masses ranging from 16 to 69 kDa, inter alia, the carboxylesterase-like urinary protein known as cauxin, previously identified in the urine of the domestic cat and other felid species, were identified in the urine fraction of the marking fluid.

Xanthene dye functionalized norbornenes for the use in ring opening metathesis polymerization

AbstractA convenient synthetic route towards polymerizable fluorescein, dicholorofluorescein, and eosin dyes is presented. Polymerizability was provided by linking 2‐norbornene carboxylic acid, 11‐bromo‐undecyl ester to the dye's carboxylate functionality. Although the monomers bearing dichlorofluorescein and eosin were obtained in high yield, the related fluorescein bearing monomer could only be obtained in low yield. In the latter case, concurring etherification and esterification led to a product mixture of the desired carboxy modified monomer and a double substituted by‐product. The dye‐monomers were used successfully for the preparation of statistical copolymers with endo,exo‐2,3‐norbornene dicarboxylic acid dimethylester by ROMP. Absorption and luminescence characteristics and, in particular, the acid/base sensitive behavior of the parent dyes were preserved in the monomers and copolymers. The absorption and emission maxima in THF solution and in the solid state were red shifted in comparison to the aqueous samples of the parent dyes. Dye‐copolymers exhibited good film forming properties. Solid state luminescence studies of the copolymers revealed an increasing sensitivity towards NEt3 vapor in the order fluorescein < dichlorofluorescein < eosin bearing copolymer. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1336–1348, 2007

Intercalation of esters into vanadyl phosphate

Intercalates of vanadyl phosphate with formates and acetates of C 1–C 8 alcohols and dimethylesters of dicarboxylic acids C 2–C 6 were prepared by a displacement reaction of 2-propanol-intercalated VOPO 4. The diffractograms of the intercalates show a series of sharp (0 0 l) reflections, (2 0 0) reflection and in some cases several ( h k l) lines with low intensity. The tetragonal lattice parameters of the intercalates were calculated. The intercalates prepared are not stable in air. The C=O stretching vibration in IR spectra of the intercalates prepared was shifted to lower wavenumbers in comparison with the spectra of the pure guests, indicating that all esters are anchored to the host layers by their carbonyl oxygen.

Synthesis and properties of noncoplanar rigid‐rod aromatic polyhydrazides and poly(1,3,4‐oxadiazole)s containing phenyl or naphthyl substituents

AbstractTwo new phenyl‐ and naphthyl‐substituted rigid‐rod aromatic dicarboxylic acid monomers, 2,2′‐diphenylbiphenyl‐4,4′‐dicarboxylic acid (4) and 2,2′‐di(1‐naphthyl)biphenyl‐4,4′‐dicarboxylic acid (5), were synthesized by the Suzuki coupling reaction of 2,2′‐diiodobiphenyl‐4,4′‐dicarboxylic acid dimethyl ester with benzeneboronic acid and naphthaleneboronic acid, respectively, followed by alkaline hydrolysis of the ester groups. Four new polyhydrazides were prepared from the dicarboxylic acids 4 and 5 with terephthalic dihydrazide (TPH) and isophthalic dihydrazide (IPH), respectively, via the Yamazaki phosphorylation reaction. These polyhydrazides were amorphous and readily soluble in many organic solvents. Differential scanning calorimetry (DSC) indicated that these hydrazide polymers had glass transition temperatures in the range of 187–234 °C and could be thermally cyclodehydrated into the corresponding oxadiazole polymers in the range of 300–400 °C. The resulting poly(1,3,4‐oxadiazole)s exhibited Tg's in the range of 252–283 °C, 10% weight‐loss temperature in excess of 470 °C, and char yield at 800 °C in nitrogen higher than 54%. These organo‐soluble polyhydrazides and poly(1,3,4‐oxadiazole)s exhibited UV–Vis absorption maximum at 262–296 and 264–342 nm in NMP solution, and their photoluminescence spectra showed maximum bands around 414–445 and 404–453 nm, respectively, with quantum yield up to 38%. The electron‐transporting properties were examined by electrochemical methods. Cyclic voltammograms of the poly(1,3,4‐oxadiazole) films cast onto an indium‐tin oxide (ITO)‐coated glass substrate exhibited reversible reduction redox with Eonset at −1.37 to −1.57 V versus Ag/AgCl in dry N,N‐dimethylformamide solution. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6466–6483, 2006

Vapor Pressures, Enthalpies of Vaporization, and Critical Parameters of a Series of Linear Aliphatic Dimethyl Esters of Dicarboxylic Acids

Vapor pressures and the molar enthalpies of vaporization of the linear aliphatic dimethyl esters of dicarboxylic acids CH3-CO2-(CH2)n-CO2-CH3 with n = (0 to 8) have been determined by the transpiration method. A linear correlation of enthalpies of vaporization (at T = 298.15 K) of the esters studied with the number n and with the Kovat's indices and has been found. The critical temperatures and pressures of the esters with n = (0 to 6) and n = 8 have been measured by the pulse-heating method with the residence times ranging from (0.03 to 1) ms. Experimental data on the critical properties are compared with the estimations by group contribution methods by Constantinou and Gani and by Marrero and Gani. Both methods considerably underestimate the critical temperatures of the esters studied; however, the method by Marrero and Gani provides the prediction of the critical pressures of the esters with an average absolute error approximately equal to the uncertainty of the measurements.

Determination of the carbon deficiency in the flame ionization detector response of long-chain fatty acid methyl esters and dicarboxylic acid dimethyl esters

Carbon deficiencies (CDs) of long-chain fatty acid methyl esters (FAMEs) and dicarboxylic acid dimethyl esters (DDMEs), which lead to decreased response in a flame ionization detection (FID) system, were determined by using full responding hydrocarbons (heptadecane, eicosane and alpha-cholestane) as references. For saturated FAMEs ranging from C 12 to C 22 and for DDMEs ranging from C 4 to C 10, CDs between 1.3 ± 0.12 and 1.7 ± 0.36 per ester group were recorded. All values were significantly ( P < 0.05) greater than 1. Generally, response factors for gas-chromatographic analysis using FID have been calculated on the theory that the CD of FAMEs is 1 per ester group. However, this theory could not be confirmed experimentally for short-chain FAMEs of less than 8 carbons as CDs of around 1.5 were reported for C 4 and C 6 FAMEs. The study presented here contributes an approach to this problem by confirming the validity of response factors calculated from a CD of 1.5 per ester group as well as for long-chain FAMEs and DDMEs.

Semiquantitative GC/MS analysis of thermochemolysis products of soil humic acids with various degrees of humification

Thermochemolysis with tetramethylammonium hydroxide (TMAH) was conducted for 18 humic acids (HAs) obtained from a wide range of soils, and the yields and compositions of the released compounds were analyzed in terms of the degree of humification and the proportions of C species estimated by 13C CPMAS NMR. Eighty-six peaks could be assigned on GC/MS chromatograms, and notable differences in the kind of compound assigned were not found among the HAs. The total yields of aliphatic compounds ranged from 0.40 to 4.2 mg/g. C 12- to C 18-even fatty acid methyl esters (FAMEs) accounted for 30–66% of the entire aliphatic compounds assigned, followed by C 20- to C 34-even FAMEs (4.8–47%), C 9- to C 33-odd FAMEs (11–26%), and C 16- to C 30-even dicarboxylic acid dimethyl esters (DAMEs; 0.3–9.1%). The total yields of aliphatic compounds decreased with decreasing gross alkyl C during the progress in the degree of humification, although their proportion in gross alkyl C was small. On the other hand, the total yields of aromatic compounds ranged from 1.7 to 37 mg/g. Of these, 7.5–82% and 0.12–64% were phenol derivatives that were possibly derived from lignin and benzenepolycarboxylic acid polymethyl esters, respectively. The yields of phenol derivatives and stilbene compounds, possibly originating from lignin dimers, decreased with an increase in the degree of humification, contrary to the increase in the proportion of aromatic C in total C. The yields of heterocyclic compounds, namely, indole and proline derivatives, were also higher in HAs with lower degrees of humification. The variation in the yield of benzenepolycarboxylic acid polymethyl esters suggested parallel progression of oxidation with increasing degree of humification. Aromatic compounds responsible for the high aromaticity and the dark color of HAs, such as quinones and polycyclic compounds, were not detected even in HAs with a high degree of humification.

Synthesis of α,ω‐Dicarboxylic Acid Dimethyl Esters from Cycloalkanones.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Structural Components of Humic Acids as Determined by Chemical Modifications and Carbon‐13 NMR, Pyrolysis‐, and Thermochemolysis‐Gas Chromatography/Mass Spectrometry

The chemical structure of humic acids (HAs) extracted from a grassland surface soil and peat were studied using bleaching (NaClO2 oxidation) and acid hydrolysis (6 M HCl) in combination with advanced analytical techniques: solid‐state 13C nuclear magnetic resonance (NMR), pyrolysis‐gas chromatography/mass spectrometry (GC/MS), and tetramethylammonium hydroxide (TMAH) thermochemolysis‐GC/MS. The purpose of the chemical treatments was to remove known structural fragments from the HA to study the building blocks and components of the macromolecule. Bleaching the peat HA resulted in an attack on the lignin structures leading to a significant reduction in the C‐substituted and O‐substituted aromatic C peaks (128 and 150 ppm) in the 13C NMR spectrum. However, the bleached soil HA still contained residual aromatic C, suggesting that part of its aromaticity had originated from aromatic structures resistant to bleaching, possibly black C (charcoal). The pyrolysates of the bleached HAs contained mainly alkanes and alkenes (C8 to C29), whereas TMAH thermochemolysis yielded a homologous series of long‐chain fatty acid methyl esters (FAMEs) (C8 to C32) and dicarboxylic acid dimethyl esters (DAMES). The data are comparable with those obtained from pyrolysis and thermochemolysis of plant cuticular materials, and therefore suggest that cuticular residues are an integral part of the HA macromolecule. The acid hydrolysis treatment removed esters, amides, carbohydrates, and some of the N‐containing compounds from the HAs. This study demonstrates the effectiveness of bleaching and hydrolysis treatments together with advanced analytical techniques for characterization of aliphatic, lignin‐derived (LG) and nonhydrolyzable N‐containing structures associated with the HA macromolecule.

Unexpected Hydrodeiodo Sonogashira−Heck−Casser Coupling Reaction of 2,2‘-Diiodobiphenyls with Acetylenes

2,2'-Diiodobiphenyl-4,4'-dicarboxylic acid dimethyl ester (3) undergoes either a ring-closure reaction with phenylacetylene to give 4 or hydrodeiodo phenylethynylation to give 5 under the catalytic conditions of Pd(OAc)(2)/CuI/phosphine in amines. In these reactions, the amine and the phosphine ligands play important roles in controlling the reactivity. Among the ligands we used, tris(o-tolyl)phosphine is the best ligand for hydrodeiodo phenylethynylation, while the bidentate phosphine ligand retards both of the reactions. On the basis of our results, we propose that 5 is formed through a fast hydrodeiodination, followed by a Sonogashira phenylethynylation. The results of the deuterium labeling experiments show that proton exchange between the acetylenic proton and the alkyl protons of amine occurs effectively under the reaction conditions. In addition, the hydrogen that replaces the iodide in the hydrodeiodination process arises mainly from the acetylenic proton.

Structural Characterization of Soil Organic Matter and Humic Acids in Particle‐Size Fractions of an Agricultural Soil

Organic matter (OM) in agricultural soils consists mainly of partially decomposed plant residues, microbial biomass, and humic substances. The advanced analytical techniques of 13C nuclear magnetic resonance (NMR), tetramethylammonium hydroxide (TMAH) thermochemolysis‐gas chromatography (GC)/mass spectroscopy (MS), and pyrolysis‐GC/MS (Py‐GC/MS) were employed to study the chemical structure of bulk soil organic matter (SOM) and its corresponding humic acid (HA) extracts from different aggregate‐size fractions (&lt;2 and &gt;250 μm) of a dark brown Mediterranean soil. The main products released by TMAH thermochemolysis of the bulk soil and HA samples were: lignin‐derived compounds (LG) and nonlignin‐derived aromatic compounds, heterocyclic N, fatty acid methyl esters (FAMEs), and dicarboxylic acid dimethyl esters (DAMEs). The TMAH chromatogram of the &gt;250‐μm size fraction revealed more LG than that of the &lt;2‐μm fraction. The relative intensity of the long‐chain FAMEs and DAMEs peaks decreased with aggregate size, but their presence highlights the contribution of aliphatic biopolymers to the structure of the SOM. Both Py‐GC/MS and TMAH‐thermochemolysis data suggest that the HAs contain large portions of lignin and cuticular materials in their structure. With decreasing particle size, the HA contained more lignin‐derived units in the final stages of oxidation, more fatty acids originating from microbial activity, and higher contents of aromatic nonlignin‐derived structures. Our data suggest that a steady‐state situation exists for the presence of HA, where fresh OM is being decomposed and humified into the HA‐like structures, but this fraction is subject to further decomposition (mainly through loss of O–alkyl and transformation of O‐substituted aromatic carbons) as humification proceeds.

Synthesis of α,ω-Dicarboxylic Acid Dimethyl Esters from Cycloalkanones

Reaction of cycloalkanones with [hydroxy(2,4-dinitrobenzenesulfonyloxy)iodo]benzene and subsequent treatment of α-[(2,4-dinitrobenzene)sulfonyl]oxy cycloalkanone intermediates with Oxone® and PTSA in MeOH-H 2 O (6:1, v/v)solution provided dicarboxylic acid dimethyl esters in high yields.

A prolyl endopeptidase-inhibiting benzofuran dimer from Polyozellus multiflex.

A new benzofuran dimer, 5,6,5',6'-tetrahydroxy[3,3']bibenzofuranyl-2,2'-dicarboxylic acid dimethyl ester (kynapcin-24), was isolated from Polyozellus multiflex and shown to noncompetitively inhibit prolyl endopeptidase (PEP), with an IC(50) value of 1.14 microM. Kynapcin-24 was less inhibitory to other serine proteases such as chymotrypsin, trypsin, and elastase.

Conformational preferences of the 1,2-hydrazine dicarboxylic acid dimethyl ester. A comparison with the hydrazide analogue

A conformational study of 1,2-hydrazine dicarboxylic acid dimethyl ester using quantum mechanical methods is presented. Gas-phase calculations have been performed at the ab initio level including electron correlation effects. The effects of aqueous and carbon tetrachloride solvents have been evaluated using a self-consistent reaction-field. The main trends predicted for the –COO–NH–NH–COO– moiety have been compared with those previously obtained for the –CO–NH–NH–CO– moiety of the N,N′-diacetylhydrazine, which were computed at the same levels of theory.

Polyesters ofω-Unsaturated Fatty Acid Derivatives

Unsaturated polyesters, based on ω-unsaturated fatty acid esters from oleochemical resources and petrochemical diols, were synthesized via two different synthetic pathways. 9-decenoic and 10-undecenoic acid methyl ester I a, b were transesterified with petrochemical diols to produce the α,ω-alkylene di(un)decenoates II a–d, which were subsequently converted into unsaturated polyesters by acyclic diene metathesis polymerization. A screening of ten homogeneous and heterogeneous metathesis catalysts was performed, implying optimum results for B2O3—Re2O7/Al2O3—SiO2 + SnBu4. Molecular weights (M̄w) up to 100 000 g/mol were determined by MALLS-GPC. On the other hand, C10 , C11 and C14-ω-unsaturated fatty acid methyl esters Ia–c were metathetically dimerized using homogeneous ruthenium and tungsten carbene complexes at an extremely low catalyst concentration. The resulting symmetrical, internally unsaturated, dicarboxylic acid dimethyl esters IIIa–c were polycondensated in bulk with conventional transesterification catalysts achieving molecular weights (M̄w) up to 110 000 g/mol. Melting temperatures of 6 to 92°C were determined by DSC.

Reactions of 4,4′-difluoro-biphenyl-3,3′-dicarboxylic acid dimethyl ester with amino alcohols. A convenient route to biphenyl tetra-alcohols

An efficient method for the preparation of biphenyl tetraols 10– 15 and 18 is described. These poly-functional products should prove valuable as scaffolds for combinatorial library construction and as core structural units for dendrimer synthesis.

Pyrolysis methylation—mass spectrometry of whole soils

SummaryIn‐source pyrolysis field ionization mass spectrometry (Py‐FIMS) and Curie–point pyrolysis gas chromatography/mass spectrometry (Py‐GC/MS) have been applied to the characterization of whole soils methylated off–line and on–line by two methylation reagents. Samples of a gleysolic Ap–horizon and a podzolic Bh horizon (Corg concentrations 2–3%) were investigated by conventional on–line and developed off–line methylation with tetramethylammonium hydroxide (TMAH) and by off–line methylation with diazomethane. For the first method, the soils were dried, milled and pretreated with TMAH for 10 min at 250°C at ambient pressure outside the pyrolyzers. For the second method, the dried and milled soils were methylated with an ether solution of diazomethane for 12 h at room temperature (∼20°C). Pyrolysis methylation with TMAH enabled aliphatic C2–C39 monocarboxylic acid methyl esters, C4–C30 dicarboxylic acid dimethyl esters and benzenecarboxylic acid methyl esters to be detected. Methoxybenzenes from phenols, benzenediols and benzenetriols, methoxybenzenecarboxylic acid methyl esters from phenolic acids and furancarboxylic acid methyl esters from carbohydrates were also identified. Nitrogen–containing compounds in soil organic matter were obtained as N,N–dimethylamides. Using diazomethane as methylation reagent, distinct Py‐FIMS signals were observed for aliphatic C2–C32 monocarboxylic acid methyl esters and C3–C24 dicarboxylic acid dimethyl esters. Additionally, methoxybenzenes originating from lignins, methoxybenzenecarboxylic acid methyl esters from phenolic acids and N,N–dimethylamides from amides were detected. The more acid podzolic Bh horizon showed higher relative intensities for dicarboxylic acid dimethyl esters and methylated phenolic acids compared to the gleysolic Ap horizon. Similarly, benzenecarboxylic acids are connected mainly by ester linkages to the macromolecular network of soil organic matter. Both methylation procedures support conventional Py‐FIMS and Py‐GC/MS and give valuable additional information on the occurrence of aliphatic and aromatic carboxylic acids, substituted phenols, benzenediols, benzenetriols, phenolic acids and amides in soil organic matter.