Unsaturated Carboxylic Acids Research Articles

Efficient and selective formation of unsaturated carboxylic and phenylacetic acids from diketene.

A nickel catalyst promotes the multicomponent coupling reaction of diketene, an alkyne, and Me2Zn to provide 3-methylene-4-hexenoic acids in excellent yields. Under similar conditions, the combination of the nickel catalyst and Et2Al(OEt) promotes a cycloaddition reaction involving dimerization of an alkyne to furnish phenylacetic acids. In the presence of PPh3, a formal [2+2+1+1] cycloaddition reaction proceeds to afford regioisomeric phenylacetic acids via cleavage of the C=C bond.

Efficient and Selective Formation of Unsaturated Carboxylic and Phenylacetic Acids from Diketene

AbstractA nickel catalyst promotes the multicomponent coupling reaction of diketene, an alkyne, and Me2Zn to provide 3‐methylene‐4‐hexenoic acids in excellent yields. Under similar conditions, the combination of the nickel catalyst and Et2Al(OEt) promotes a cycloaddition reaction involving dimerization of an alkyne to furnish phenylacetic acids. In the presence of PPh3, a formal [2+2+1+1] cycloaddition reaction proceeds to afford regioisomeric phenylacetic acids via cleavage of the CC bond.

Review of old chemistry and new catalytic advances in the on-purpose synthesis of butadiene.

Increasing demand for renewable feedstock-based chemicals is driving the interest of both academic and industrial research to substitute petrochemicals with renewable chemicals from biomass-derived resources. The search towards novel platform chemicals is challenging and rewarding, but the main research activities are concentrated on finding efficient pathways to produce familiar drop-in chemicals and polymer building blocks. A diversity of industrially important monomers like alkenes, conjugated dienes, unsaturated carboxylic acids and aromatic compounds are thus targeted from renewable feedstock. In this context, on-purpose production of 1,3-butadiene from biomass-derived feedstock is an interesting example as its production is under pressure by uncertainty of the conventional fossil feedstock. Ethanol, obtained via fermentation or (biomass-generated) syngas, can be converted to butadiene, although there is no large commercial activity today. Though practised on a large scale in the beginning of the 20th century, there is a growing worldwide renewed interest in the butadiene-from-ethanol route. An alternative route to produce butadiene from biomass is through direct carbohydrate and gas fermentation or indirectly via the dehydration of butanediols. This review starts with a brief discussion on the different feedstock possibilities to produce butadiene, followed by a comprehensive summary of the current state of knowledge regarding advances and achievements in the field of the chemocatalytic conversion of ethanol and butanediols to butadiene, including thermodynamics and kinetic aspects of the reactions with discussions on the reaction pathways and the type of catalysts developed.

A mechanistic study of allene carboxylation with CO2resulting in the development of a Pd(ii) pincer complex for the catalytic hydroboration of CO2

The carboxylation of allenes with CO2 represents a potentially important method for the synthesis of unsaturated carboxylic acids. Here, we describe a detailed mechanistic study of the catalytic carboxylation of allenes using CyPSiP (CyPSiP = Si(Me)(2-PCy2-C6H4)2) supported Pd complexes. As part of this work we have identified, characterized and isolated all of the proposed intermediates in the catalytic cycle and shown that they are kinetically competent catalysts. In addition, we have isolated several off-cycle species, which are in equilibrium with complexes in the catalytic cycle, and established that they are also active catalysts. Several of these off-cycle species are formed through an unusual ligand rearrangement of the CyPSiP pincer ligand, in which a Si–C bond is reversibly cleaved. The major catalyst deactivation pathway has been identified. Furthermore, our mechanistic study has allowed us to develop a new catalyst for the hydroboration of carbon dioxide, which gives a maximum turnover number (TON) greater than 60 000; the highest reported to date.

ChemInform Abstract: Copper‐Catalyzed Oxidative Coupling of Carboxylic Acids with Formamides for the Synthesis of α,β‐Unsaturated Amides.

Abstract A novel and efficient protocol for the synthesis of α,β-unsaturated amides has been developed using catalytic amount of Cu(OAc) 2 and TBHP as an available oxidant. Oxidative coupling of various unsaturated carboxylic acids with N,N-disubstituted formamides was examined to furnish the desired products in good yields.

Research on Polycarboxylic Superplasticizer with Slump Retaining

Adopting methyl allyl polyoxyethylene ether (TPEG) and unsaturated carboxylic acid throught REDOX system synthetize the polycarboxylic slump retaining admixture. Researching the impact factors of temperature,reaction time, acid alcohol ratio, dosage of initiator and molecular regulator to the polycarboxylic superplasticizer with slump retaining.In the circumstance of reaction temperature is 45°C, reaction time is 4 hours, acid alcohol ratio is 1:3.25,dosages of initiator and molecular regulator are 0.27% and 4% by weight.. Using infrared spectroscopy(IR) to characterize the molecular structure of polycarboxylic superplasticizer with slump retaining.

Effect of Triclosan on Self‐Assembly of Alkyl Ammonium Surfactants Adsorbed within Montmorillonite Galleries in Silicone Elastomer Composites

SummaryPoly(propylene) homopolymer/fly ash (50% wt) composites have been prepared from two samples of fly ash that differ in terms of the geographic source of coal feedstock, which left one of the samples with a higher group I and II metal content. A screening study indicated that Lubrizol Solplus® C800 (an unsaturated carboxylic acid dimer coupling agent), initiated with dicumyl peroxide, conferred the best strength–toughness balance to the composites. In some cases, however this was related to detachment of the interfacial region due to possible extraction of PP‐C800 adduct‐group I and II ion reaction products. Interfacial adhesion was arguably too high in the case of the fly ash sample bearing a lower level of group I and II ions. These deductions were also supported by DSC data.

Poly(propylene)/Fly Ash Composites: Effect of Coupling Agents on Mechanical Properties and Matrix Crystallinity

SummaryPoly(propylene) homopolymer/fly ash (50%wt) composites have been prepared from two samples of fly ash. One of the samples has a greater soluble group I and II metal content. A screening study indicated that Lubrizol Solplus® C800 (an unsaturated carboxylic acid coupling agent), initiated with dicumyl peroxide (DCP), conferred the best strength–toughness balance to composites produced by small scale batch mixing followed by compression moulding, i.e. long residence time in the melt. In the latter case, however the good mechanical properties were related to detachment of the interfacial region due to possible extraction of PP‐C800 adduct‐group I and II ion reaction products. Interfacial adhesion was arguably too high in the case of the fly ash sample bearing a lower level of group I and II ions. These deductions were also supported by DSC data. However, higher shear ‐ low residence time processing, i.e. by twin screw extrusion and injection moulding, led to better mechanical properties being obtained from C800‐DCP modification when the fly ash contained a reduced level of soluble group I and II ions.

Colloid and nanodimensional catalysts in organic synthesis: I. Investigation of hydrogenation selectivity of unsaturated compounds with hydrazine hydrate and aluminum hydride

Results of investigation of selective hydrogenation of unsaturated carbon-carbon bonds with hydrazine hydrate or complex metal hydrides in the presence of metal nanoparticles are reported. Conditions of exhaustive and partial hydrogenation of some derivatives of norbornene, styrene, and unsaturated carboxylic acids are developed.

Variations in the saturation magnetization of nanosized NiFe2O4 particles on adsorption of carboxylic acids

This work investigated magnetization changes in NiFe2O4 nanoparticles induced by the adsorption of a series of carboxylic acids. The application of formic acid resulted in a significant 8.6% decrease in the magnetization of NiFe2O4 nanoparticles at 18,000 Oe. With increasing carbon bond number in the saturated carboxylic acids, reductions in the magnetization of NiFe2O4 nanoparticles became around 4%. All unsaturated carboxylic acids produced approximately equivalent reductions in the magnetization, regardless of their double bond content. Based on these results, the observed NiFe2O4 magnetization changes appear to depend on either the polarity or the molecular size of the carboxylic acids and are believed to be caused by canting or pinning of spins in the vicinity of particle surfaces following adsorption of the acids.

ChemInform Abstract: Synthesis of Substituted Nitroolefins: A Copper Catalyzed Nitrodecarboxylation of Unsaturated Carboxylic Acids.

AbstractA novel, mild and convenient method for the nitrodecarboxylation of cinnamic acids using tBu‐O‐NO as nitrating source is developed.

New trends in vinyl ester resins

AbstractVinyl ester resins (VERs) are high-performance unsaturated resins derived by the addition reaction of various epoxide resins with α-β unsaturated carboxylic acids. These resins have always been classified under unsaturated polyester resins. However, VERs have remarkable corrosion resistance and superior physical properties as compared with these conventional polyester resins, which make VERs a class of their own and hallmark of today’s resin industries. Hence, there is a need to review the available literature on this important class of thermosetting resins separately. In this article, an attempt is made to review the state of the art of VERs, including synthesis, characterization, curing, thermal, chemical, oxidative properties, and applications. The main focus is on the latest developments in this area.

Lewis acid-catalyzed tandem acylation–Nazarov cyclization for the syntheses of fused cyclopentenones

Treatment of N-tosylpyrroles or N-tosylindoles with α-unsubstituted α,β-unsaturated carboxylic acids or unsaturated carboxylic acids having an α electron-withdrawing substituent in the presence of TFAA and a Lewis acid catalyst resulted in the formation of fused cyclopentenones via a tandem acylation–Nazarov cyclization sequence, while either the acylation product obtained or no reaction occurred in the absence of the Lewis acid catalyst.

Comparison of Unimolecular Decomposition Pathways for Carboxylic Acids of Relevance to Biofuels

Quantum mechanical molecular modeling is used [M06-2X/6-311++G(2df,p)] to compare activation energies and rate constants for unimolecular decomposition pathways of saturated and unsaturated carboxylic acids that are important in the production of biofuels and that are models for plant and algae-derived intermediates. Dehydration and decarboxylation reactions are considered. The barrier heights to decarboxylation and dehydration are similar in magnitude for saturated acids (∼71 kcal mol(-1)), with an approximate 1:1 [H2O]/[CO2] branching ratio over the temperature range studied (500-2000 K). α,β-Unsaturation lowers the barrier to decarboxylation between 2.2 and 12.2 kcal mol(-1) while increasing the barriers to dehydration by ∼3 kcal mol(-1). The branching ratio, as a result, is an order of magnitude smaller, [H2O]/[CO2] = 0.07. For some α,β-unsaturated acids, six-center transition states are available for dehydration, with barrier heights of ∼35.0 kcal mol(-1). The branching ratio for these acids can be as high as 370:1. β,γ-Unsaturation results in a small lowering in the barrier height to decarboxylation (∼70.0 kcal mol(-1)). β,γ-Unsaturation also leads to a lowering in the dehydration pathway from 1.7 to 5.1 kcal mol(-1). These results are discussed with respect to predicted kinetic values for acids of importance in biofuels production.

Cellular Toxicity Associated with Exposure to Perfluorinated Carboxylates (PFCAs) and Their Metabolic Precursors

The biotransformation of fluorotelomer based compounds yields saturated and unsaturated fluorotelomer aldehydes (FTALs and FTUALs, respectively) and carboxylic acids (FTCAs and FTUCAs, respectively) as intermediate metabolites that subsequently transform to perfluorinated carboxylic acids (PFCAs). Previous studies have demonstrated that the FTCAs and FTUCAs are 1 to 5 orders of magnitude more toxic than PFCAs after exposure to aquatic organisms. Additionally, FTUALs have demonstrated reactivity with proteins, which may be associated with toxicity through the inhibition of protein function. The purpose of this study was to carry out a comprehensive assessment of the relative toxicity between PFCAs and their intermediate precursor metabolites: the FTALs, FTUALs, FTCAs, and FTUCAs. Analytes were separately incubated with human liver epithelial (THLE-2) cells to assess how varying the functional group and the fluorinated chain length affects cell viability. For each analyte, dose-response EC50 values were calculated. The EC50 values for FTUCAs and FTCAs were similar, with values ranging from 22 ± 9 and 24 ± 9 μM for the 10:2 congeners to 1004 ± 20 and 1004 ± 24 μM for the 4:2 congeners, respectively. The EC50 values for the PFCAs ranged from 65 ± 41 (PFDA) to 1361 ± 146 (PFBA) μM. The range of toxicity between PFCAs and their acid precursors were similar. However, the comparative toxicity between the 6:2 and 8:2 congeners and their corresponding PFCA had toxicity thresholds that varied depending on the functional headgroup, where FTUALs ≥ FTALs > FTUCAs ≥ FTCAs > PFCAs. For all PFCAs and acid precursors, toxicity depended on the length of the fluorinated chain, where the longer chain lengths yielded greater bioaccumulation and enhanced toxicity, results which agreed with those previously reported. By contrast, FTALs and FTUALs were the most toxic of all the analytes examined, where toxicity was enhanced at shorter chain lengths, with EC50 values of 7 ± 1 μM (6:2 FTUAL) and 8.6 ± 0.8 μM (6:2 FTAL). DNA adducts were not detectable for the aldehyde precursors, using a quantitative long-range PCR method. Our data provide the first evidence that aldehyde intermediates have demonstrated toxicity in cellular systems that is more significant than PFCAs and their corresponding acid intermediates.

Composition and Source Apportionment of Organic Aerosol in Beirut, Lebanon, During Winter 2012

Fine organic aerosols were collected at a semi-urban site in Beirut, Lebanon, from 28 January to 12 February 2012 as part of the Emission and Chemistry of Organic Carbon in East Mediterranean-Beirut (ECOCEM-Beirut). A total of 20 quartz filter samples were collected on a 12 h basis using a high-volume sampler and were analyzed using a GC/MS technique. Levoglucosan was the major most abundant single component with an average value of 306 ng.m−3, followed by saturated and unsaturated carboxylic acids and sugars with average values of 234 and 118 ng.m−3, respectively. Reported values for other carboxylic acids, polycyclic aromatic hydrocarbons, and biogenic secondary organic aerosols (BSOA) were 87, 33 and 21 ng.m−3, respectively. Compared to a similar field campaign conducted in summer 2011, levoglucosan concentrations were lower in summer by a factor of 6, due to the use of wood burning for residential heating in winter. Concentrations of saturated and unsaturated carboxylic acids, other carboxylic acids, and BSOA were higher in summer by a factor of 3, 2, and 7, respectively. Higher concentrations observed for BSOA and other dicarboxylic acids during summer are due to higher biogenic emissions and greater photochemical activity in summer. Copyright 2013 American Association for Aerosol Research

Effect of coupling agents on the degradation of polypropylene/fly ash composites

ABSTRACTComposites containing 50% wt fly ash (sourced from the UK and South Africa) in polypropylene homopolymer (manufacturer stabilized for general purpose use) have been prepared by using batch and continuous methods. The effect of the following coupling agents were investigated on the photo‐ and thermal‐decomposition of the composite materials: Lubrizol Solplus C800 (an unsaturated carboxylic acid), γ‐methacryloxypropyl trimethoxy silane (γ‐MPS), 1,3‐phenylene dimaleimide (BMI), and maleic anhydride‐grafted‐polypropylene (m‐PP). High melt, thermal‐, and photo‐stability was favored when the matrix was coupled to the filler surface by monomeric coupling agents that were expected to adsorb in a close packed layer on the fly ash surface. Further improvements were observed in cases where the coupling agent could also self‐polymerize. m‐PP did not lead to increased stability due to its low adsorption density on the fly ash surface. The relatively high water/acid soluble transition metal ion content of the UK sourced fly ash did not appear to affect stability under the test conditions employed in this study. The South African sourced fly ash had a higher level of quartz and mullite together with a high level of group 1 and 2 metals. The latter in particular may have led to debonding of the coupled interfacial region from the filler surface and possible adsorption of stabilizers on the pristine surface. This resulted in the South African fly ash generally possessing poorer resistance to oxidation than the UK fly ash. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014, 131, 39974.

Effect of fly ash washing conditions on the properties of coupling agent modified polypropylene/fly ash composites

Two fly ash samples (one from UK, UKFA, and another from South Africa, SAFA) were washed with water and 1 M hydrochloric acid (followed by water) prior to incorporation (at 65% wt) into polypropylene homopolymer, containing an unsaturated carboxylic acid coupling agent (Lubrizol Solplus® C800) with dicumyl peroxide free radical initiator. Melt blending was achieved using a Haake Rheomix 600 mixing chamber, and composite test plaques were compression moulded. Flexural and impact testing was then carried out. Unwashed and water washed fly ash–based composites responded well to C800 modification, and flow microcalorimetry (FMC) and diffuse reflectance Fourier transform infrared spectroscopy studies confirmed strong interaction between C800 and fly ash. However, washing the fly ash with HCl led to a reduction in composite flexural and impact properties. Scanning electron microscopy imaging of the latter composite fracture surfaces revealed poor filler‐matrix adhesion, which was thought to be due to reduced interaction between C800 and HCl washed fly ash. The latter was confirmed using FMC. Reduction of C800/fly ash interaction led to a reduction in the nucleation of polypropylene (PP) crystallization and a decrease in melt flow rate. The latter may be due to a shift in locus of PP–C800 addition reactions from the interfacial region to the bulk matrix. POLYM. COMPOS., 35:698–707, 2014. © 2013 Society of Plastics Engineers

Visible light-induced decomposition of a fluorotelomer unsaturated carboxylic acid in water with a combination of tungsten trioxide and persulfate

Photochemical decomposition of a fluorotelomer unsaturated carboxylic acid, C3F7CFCHCOOH (1), in the presence of WO3 and an electron acceptor (S2O82- or H2O2) in water under visible-light irradiation was investigated. Under an O2 atmosphere, 1 was not decomposed either by TiO2 (P25) or WO3 alone. A combination of WO3 and H2O2 also resulted in almost no decomposition of 1. In contrast, irradiation in the presence of a combination of WO3 and S2O82- (potassium salt) efficiently decomposed 1 to F−, CO2, C3F7COOH, and C2F5COOH. The decomposition of 1 was affected by the counter cation of S2O82-: the decomposition extent was higher with K2S2O8 than with (NH4)2S2O8. The decomposition of 1 was further enhanced when the reaction in the presence of WO3 and K2S2O8 was carried out under an argon atmosphere. Under O2, the amount of H2O2 formed in the reaction solution was an order of magnitude higher than the amount formed under argon. This fact suggests that the decrease in the decomposition of 1 under O2 can be ascribed to the formation of H2O2, which consumed S2O82- and SO4-.

Scientific Opinion on Flavouring Group Evaluation 72, Revision 1 (FGE.72Rev1): Consideration of aliphatic, branched‐chain saturated and unsaturated alcohols, aldehydes, acids, and related esters evaluated by the JECFA (61st meeting) structurally related to branched‐ and straight‐chain unsaturated carboxylic acids, esters of these and straight‐chain aliphatic saturated alcohols evaluated by EFSA in FGE.05Rev2

The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (the JECFA), and to decide whether further evaluation is necessary, as laid down in Commission Regulation (EC) No 1565/2000. The present consideration concerns a group of 23 aliphatic branched-chain saturated and unsaturated alcohols, aldehydes, acids and related esters, evaluated by the JECFA at their 61st meeting. This revision is made due to inclusion of one additional substance, 2,6-dimethyl-2, 5,7-octatriene-1-ol acetate [FL-no: 09.931] cleared for genotoxicity concern in FGE.207. The substances were evaluated through a stepwise approach that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. The Panel agrees with the application of the Procedure as performed by the JECFA for all 23 substances considered in this FGE and agrees with the JECFA conclusion, “No safety concern at estimated levels of intake as flavouring substances” based on the MSDI approach. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been considered and for all 23 substances, the information is adequate.