C6 C8 Research Articles

Medium-chain carboxylates production from plant waste: kinetic study and effect of an enriched microbiome

BackgroundThe need for addition of external electron donors such as ethanol or lactate impairs the economic viability of chain elongation (CE) processes for the production of medium-chain carboxylates (MCC). However, using feedstocks with inherent electron donors such as silages of waste biomass can improve the economics. Moreover, the use of an appropriate inoculum is critical to the overall efficiency of the CE process, as the production of a desired MCC can significantly be influenced by the presence or absence of specific microorganisms and their metabolic interactions. Beyond, it is necessary to generate data that can be used for reactor design, simulation and optimization of a given CE process. Such data can be obtained using appropriate mathematical models to predict the dynamics of the CE process.ResultsIn batch experiments using silages of sugar beet leaves, cassava leaves, and Elodea/wheat straw as substrates, caproate was the only MCC produced with maximum yields of 1.97, 3.48, and 0.88 g/kgVS, respectively. The MCC concentrations were accurately predicted with the modified Gompertz model. In a semi-continuous fermentation with ensiled sugar beet leaves as substrate and digestate from a biogas reactor as the sole inoculum, a prolonged lag phase of 7 days was observed for the production of MCC (C6–C8). The lag phase was significantly shortened by at least 4 days when an enriched inoculum was added to the system. With the enriched inoculum, an MCC yield of 93.67 g/kgVS and a productivity of 2.05 gMCC/L/d were achieved. Without the enriched inoculum, MCC yield and productivity were 43.30 g/kgVS and 0.95 gMCC/L/d, respectively. The higher MCC production was accompanied by higher relative abundances of Lachnospiraceae and Eubacteriaceae.ConclusionsEnsiled waste biomass is a suitable substrate for MCC production using CE. For an enhanced production of MCC from ensiled sugar beet leaves, the use of an enriched inoculum is recommended for a fast process start and high production performance.

Elucidation of the Effect of TiO2 in the Synthesized Nanocatalyst of Co–Mo@Al2O3–TiO2 for the Hydrogenation of C6–C8 Olefins

Elucidation of the Effect of TiO2 in the Synthesized Nanocatalyst of Co–Mo@Al2O3–TiO2 for the Hydrogenation of C6–C8 Olefins

C(sp3)-H hydroxylation of Broad-Spectrum Alkanes Catalyzed by an Artificial P450 Peroxygenase Driven by ω-Pyridyl Fatty Acyl Amino Acids

Selective hydroxylation of C(sp3)–H bonds is a long-standing challenge in the organic synthesis field. We herein report an artificial P450 peroxygenase system facilitated by ω-pyridyl fatty acyl amino acids that can hydroxylate broad-spectrum alkanes, including linear and cyclic alkanes and benzylic and allylic alkane chains. Compared with the previously reported dual-functional small molecule (DFSM) with imidazole as a catalytic group (Im-DFSM), pyridyl DFSM (Pyd-DFSM) produced substantially higher total turnover numbers (TTNs) for the hydroxylation of medium-chain alkanes and cycloalkanes (C6–C8), e.g., 12.0-fold and 17.1-fold increased TTNs of P450 mutant F87A/T268V for heptane and cycloheptane, respectively. In addition, Pyd-DFSM altered the enantioselectivity of benzylic hydroxylation, e.g., it almost inverted the configuration observed in the benzylic hydroxylation of ethylbenzene and tetralin. More importantly, Pyd-DFSM showed excellent regioselectivity for allylic hydroxylation over epoxidation of terminal alkenes and cycloalkenes, e.g., up to 94% allylic hydroxylation of 1-hexene was observed. This work significantly enhances the catalytic toolbox of the DFSM-facilitated P450 peroxygenase system; it not only substantially expands the chemical space of P450 enzymes, but also provides an alternative solution for the selective hydroxylation of C(sp3)–H bonds.

Ethylene oligomerization over mesoporous FeNi-BTC catalysts: Effect of the textural properties of the catalyst on the reaction performance

Mesoporous FeNi-1,3,5-benzenetricarboxylates (FeNi-BTCs) with different Fe/Ni ratios were prepared, and their catalytic activities in ethylene oligomerization were evaluated. The textural properties of the bimetallic FeNi-BTC were considerably affected by the Fe/Ni ratio, exhibiting a volcano relationship, with the maximum specific surface area, pore volume, and diameter observed at Fe/Ni = 10/90. The enhanced textural properties of the FeNi-BTC catalyst resulted in accelerated ethylene oligomerization and an increased C6–C8 oligomer selectivity. Using the Fe10Ni90-BTC catalyst, the rate of ethylene consumption and C6–C8 oligomer selectivity reached as high as 2823 g C2H4/g Ni h and 49%, which were approximately four- and two-fold higher than those of Ni-BTC, respectively. The remarkable reaction performance of the Fe10Ni90-BTC catalyst could be rationalized in terms of its well-defined mesoporous structure, which could decrease the mass transfer resistance and thereby facilitate intrapore ethylene diffusion during ethylene oligomerization. These results clearly demonstrate the potential of the FeNi-BTC catalyst in promoting ethylene oligomerization with a high activity and selectivity towards C6∼C8 oligomers. In the catalyst recycling study, whereas the catalytic activity decreased due to the partial deformation of the FeNi-BTC catalyst with repeated recycling, the selectivity towards C6+ oligomers gradually increased.

Unexpected oxidative cracking of diformyltricyclodecanes under catalyst-free and ultra-low temperature

Abstract The oxidative cracking of diformyltricyclodecanes (DFTD) to C6–C8 alkenes and alkenes were systematically studied in this work. A series of experiments was performed over a broad range of conditions (temperature: 40–60 °C; oxygen pressure: 0–1.0 Mpa; reaction time: 5–90 min, solvent selection) for exploring the reaction route and mechanism. Results show that the higher temperature and oxygen pressure, as well as tetrahydrofuran (THF) as solvent are of benefit to the generation of cracking products. In addition, the kinetics of this reaction was explored by the dynamic fitting. The obtained kinetics parameters demonstrate that the transformation of intermediate to cracking products possesses higher activation energy than to dicarboxyltricyclodecaneacids (DCTDA), showing that higher temperature is conducive to the generation of DFTD cracking products. This work firstly demonstrated that DFTD could be formed into C6-C8 alkenes containing the same as gasoline compound by the oxidative cracking, suggesting that the by-product of petroleum and coal could be transferred into fuels; this expanded the application of DCPD and will have significant and positive influence on the petroleum and coal chemical industry.

Water-assisted single-step catalytic hydrodeoxygenation of polyethylene terephthalate into gasoline- and jet fuel-range cycloalkanes over supported Ru catalysts in a biphasic system

A single-step hydrodeoxygenation (HDO) over a Ru/TiO2 catalyst in the water/dodecane biphasic system allows for the quantitative conversion of polyethylene terephthalate (PET) to gasoline- and jet fuel-range C6–C8 cyclic hydrocarbons.

Mechanisms and Kinetics of the Dehydrogenation of C6–C8 Cycloalkanes, Cycloalkenes, and Cyclodienes to Aromatics in H-MFI Zeolite Framework

This work employs periodic density functional theory to elucidate dehydrogenation mechanisms of C6–C8 cycloalkanes, cycloalkenes, and cyclodienes into aromatics during methanol-to-olefin (MTO) chemistries in H-MFI zeolites. Aromatic compounds act as co-catalysts that predominantly form ethylene over propylene products and lead to site-blocking polyaromatic compounds; thus, understanding the formation of aromatic compounds during MTO is critical to understanding its selectivity and catalyst stability. Ring dehydrogenation reactions occur via sequential hydride transfer followed by deprotonation. The rate-controlling hydride transfer reactions were investigated with surface-bound protons (Z–H) and alkyls (Z–CnH2n+1) as hydride-accepting species. Hydride transfers via proton-mediated routes occur with intrinsic free energy barriers (623 K) of 215 kJ mol–1 for C6H12, 164 kJ mol–1 for C6H10, and 141 kJ mol–1 for C6H8, whereas methyl-mediated counterparts occur with intrinsic free barriers of 101, 95, and 81 kJ mol–1, respectively. Transition states for hydride transfer reactions prefer channel intersections within MFI networks, and their activation barriers suggest that methyl-mediated routes are favored over proton-mediated counterparts during MTO. Methyl substituents on hydrocarbon rings generally increase activation barriers for hydride transfers that occur proximal to the −CH3, partly because of steric hindrances between the hydride acceptor and ring-bound −CH3. Rapid double-bond isomerization within cyclohexenes and cyclohexadienes allows hydride transfer reactions to occur away from sterically hindering methyl substituents in methylated and dimethylated C6 ring hydrocarbons. The impact of carbocation substitution in hydride-accepting species was explored by contrasting barriers of methyl (Z–CH3), ethyl (Z–C2H5), 2-propyl (Z–C3H7), and tert-butyl (Z–C4H9) surface-bound alkyls. Intrinsic activation barriers decrease with increasing substitution of the alkyl hydride acceptor, consistent with those alkyls forming more stable carbocations. However, when accounting for steric hindrances associated with the co-adsorption of hydrocarbon rings near surface-bound alkyls, apparent free barriers are larger for more-substituted alkyls. Taking these apparent barriers into account, we predict that methyl-mediated hydride transfer reactions are responsible for the aromatization of hydrocarbon rings during MTO, leading to the CH4 formed during MTO reactions as the aromatic pool is enriched.

Group additivity values for the heat of formation of C2–C8 alkanes, alkyl hydroperoxides, and their radicals

A set of 58 group additivity values (GAV) for the calculation of the heat of formation is derived from an extensive and accurate database of 192 ab initio heats of formation. The ab initio values are from companion calculations at the CCSD(T)–F12/cc-pVTZ-F12//B2PLYPD3/cc-pVTZ level of theory employing second order connectivity based hierarchy reference reactions with ANL energies for the reference species. This database of 192 species consists of alkanes (RH), alkyl radicals (Ṙ), alkyl hydroperoxides (RO2H), alkyl-peroxy (RȮ2) radicals, and hydroperoxy-alkyl (Q˙OOH) radicals of all of the isomers of C2–C5 alkane fuels and a select set of C6–C8 isomers. The GAV and ab initio based enthalpies for this dataset show excellent agreement, with an estimated 2σ uncertainty of 0.9 kcal mol–1. Among the 58 GAV terms, 40 are refinements of previously reported terms, while 18 are newly developed. These new GAV terms are mainly non-next-nearest neighbor interactions (NNI) and β-corrections. The inclusion of these new groups significantly improves the accuracy of the GAV estimates of the heats of formation. The updated GAVs can be used with increased confidence to estimate the heats of formation of combustion relevant hydrocarbons and oxygenated hydrocarbons and their corresponding radicals, which are important in predicting low-temperature chemistry and are critical in the development of accurate chemical kinetic models.

Synthesis of Isomeric 3-Benzazecines Decorated with Endocyclic Allene Moiety and Exocyclic Conjugated Double Bond and Evaluation of Their Anticholinesterase Activity.

Transformations of 1-methoxymethylethynyl substituted isoquinolines triggered by terminal alkynes in alcohols were studied and new 3-benzazecine-containing compounds synthesized, such as 6-methoxymethyl-3-benzazecines incorporating an endocyclic C6–C8 allene fragment and the -ylidene derivatives 6-methoxymethylene-3-benzazecines. The reaction mechanisms were investigated and a preliminary in vitro screening of their potential inhibitory activities against human acetyl- and butyrylcholinesterases (AChE and BChE) and monoamine oxidases A and B (MAO-A and MAO-B) showed that the allene compounds were more potent than the corresponding -ylidene ones as selective AChE inhibitors. Among the allenes, 3e (R3 = CH2OMe) was found to be a competitive AChE inhibitor with a low micromolar inhibition constant value (Ki = 4.9 μM), equipotent with the corresponding 6-phenyl derivative 3n (R3 = Ph, Ki = 4.5 μM), but 90-fold more water-soluble.

Identification of novel polyfluoroalkyl substances in surface water runoff from a chemical stockpile fire

In 2018, over 30,000 L of fluorine-free firefighting foam was used to extinguish an industrial warehouse fire of uncharacterized chemical and industrial waste. Contaminated firewater and runoff were discharged to an adjacent freshwater creek in Melbourne, Australia. In this study, we applied nontarget analysis using liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QToF-MS) to 15 surface water samples to investigate the presence of legacy, novel and emerging per-and polyfluoroalkyl substances (PFAS). We identified six novel and emerging fluorotelomer-based fluorosurfactants in the Australian environment for the first time, including: fluorotelomer sulfonamido betaines (FTABs or FTSA-PrB), fluorotelomer thioether amido sulfonic acids (FTSASs), and fluorotelomer sulfonyl amido sulfonic acids (FTSAS-So). Legacy PFAS including C6–C8 perfluoroalkyl sulfonic acids, C4–C10 perfluoroalkyl carboxylic acids, and perfluoro-4-ethylcyclohexanesulfonate were also detected in surface water. Of note, we report the first environmental detection of ethyl 2-ethenyl-2-fluoro-1-(trifluoromethyl) cyclopropane-1-carboxylate. Analysis of several Class B certified fluorine-free foam formulations allowed for use in Australia revealed that there was no detectable PFAS. Patterns in the homologue profiles of fluorotelomers detected in surface water are consistent with environments impacted by fluorinated aqueous film-forming foams. These results provide strong evidence that firewater runoff of stockpiled fluorinated firefighting foam was the dominant source of detectable PFAS to the surrounding environment.

Simulation modelling the structure related bioaccumulation and biomagnification of per- and polyfluoroalkyl substances in aquatic food web

Until now, there is no bioaccumulation model to predict bioaccumulation of polyfluoroalkyl substances (PFASs) in aquatic organisms due to their unique amphiphilic properties. For the first time, protein contents instead of lipid contents of organisms were used in bioaccumulation models to predict the concentrations and reveal the accumulation mechanisms of PFASs in various aquatic organisms, based on the available data. Comparison between the modeled and measured results indicated the models were promising to predict the PFAS concentrations in the fishes at different trophic levels very well, as well as their bioaccumulation factors (BAF) and trophic magnification factors (TMF) of PFASs in fish. Both water and sediment are important exposure sources of PFASs in aquatic organisms. As the two main uptake pathways, the contribution of gill respiratory decreases while that of dietary intake increases with the chain length of PFASs increasing. Fecal excretion and gill respiration are the main pathways for fish to eliminate PFASs, and their relative contributions increase and decrease respectively with chain length. The short-chain (C6–C8) perfluoroalkyl acids (PFAAs) are greatly eliminated via gill respiratory quickly, leading to their very low BAFs. As the carbon chain length increases, dietary intake becomes dominant in the uptake, while elimination is mainly through fecal excretion with relatively low rates, especially in the fishes with high protein contents. For the very long chain (C12–C16) PFASs, they are very difficult to excrete with a low total elimination rate constant (ke = 0.463–0.743 d−1), thus leading to their high BAFs and TMFs. The high intake rate but low elimination rate, as well as the high water and sediment concentrations together contribute to the highest accumulated concentration perfluorooctane sulfonic acid in the fish of Taihu Lake.

Binding and Assembly of a Benzotriazole Cavitand in Water

AbstractA water‐soluble cavitand bearing a benzotriazole upper rim was prepared and characterized. It exists as a dimeric velcraplex in D2O, but forms host–guest complexes with hydrophobic and amphiphilic guests. Alkanes (C5 to C10), cyclic ketones (C6–C10), cyclic alcohols (C6–C8) and various amphiphilic guests form 1 : 1 cavitand complexes. A cyclic array of hydrogen bonds, bridged by solvent/water (D2O) molecules, stabilizes the vase conformation of the complexes. With longer alkanes (C12–C15), symmetrical dialkyl amine, urea and phosphate, 2 : 1 host:guest capsules are formed. Computations indicate that additional waters on the upper rim create a self‐complementary hydrogen‐bonding pattern for capsule formation.

Volatile organic compounds emission in the rubber products manufacturing processes

Volatile organic compounds (VOCs) emission from rubber products manufacture processes, mixing, shaping and vulcanization were investigated in four rubber products factories in China. The source emission air was passively sampled by pre-vacuumized stainless steel canister and analyzed by gas chromatography-mass spectrometry-flame ionization detection (GC/MS-FID). The species profile of 107 VOCs in the emission processes were obtained. We calculated the photochemical ozone formation potential (OFP) and carcinogenic risk (CR) of the VOCs for each manufacture process. The results showed that mixing process mainly released dichloromethane (14.53%), carbon disulfide (CS2) (6.88%), styrene (5.72%), 4-methyl-2-pentanone (5.22%) and naphthalene (3.69%) for solvents used and raw rubber degradation in the process. The C6–C8 alkanes, especially heptane and isomers of heptane (44.71%), were dominated in shaping process. The major species released from vulcanization process were carbon disulfide (29.72%), naphthalene (8.17%), acetone (7.73%) and dichloromethane (4.26%). VOCs emitted from vulcanization process had the highest OFP, which contributed by naphthalene, m/p-xylene, o-xylene and carbon disulfide. VOCs emission from mixing process had the highest CR, and 1,2-dibromoethane, 1,2-dichlorethane and 1,3-butadiene were the main contributors to CR. We also estimated the total VOCs emissions into the atmosphere from tires manufacturing in China, which were 7.58 × 105 t in 2018 and contributed about 9% of total industry processes VOCs emissions.

Improved light hydrocarbons collection method for the pyrolysis of crude oil in gold tube closed system experiments

Light hydrocarbons (C6–C13) are the major components of light oils and condensates and contain abundant geochemical information. Hence, they are widely used as important supplements to biomarker analysis. Due to high volatility, it is often difficult to collect light hydrocarbons completely after pyrolysis experiments. The traditional liquid hydrocarbon (TLH) collection method is usually applied to collect liquid hydrocarbon products after gold tube closed-system pyrolysis experiments. However, this method is difficult to adequately inhibit the evaporation of light hydrocarbons, which may cause deviations in the evaluation of generation potential, applications of parameters, and stable carbon isotopic compositions of light hydrocarbons. Hence, we have developed an alternative method of liquid nitrogen direct freezing (LNDF) to collect liquid hydrocarbon products after pyrolysis of a crude oil in closed gold tubes. The yields, molecular and stable carbon isotopic compositions of light hydrocarbons collected are compared with the TLH method to evaluate any differences. In addition, the influence of thermal alteration on the characteristics of light hydrocarbons are discussed. The yields of light hydrocarbons by the TLH method are 10–75% less than that by the LNDF method, which may bring about an underestimate of light hydrocarbon generation potential. The maturity corresponding to the maximum light hydrocarbon yield determined by the TLH method is at Easy%Ro = 1.08, much lower than Easy%Ro = 1.67 by the LNDF method. Relative to the LNDF method, the TLH method reveals significant differences in some light hydrocarbon parameters and C6–C8 carbon isotopes, which may cause deviations in their geochemical applications such as oils correlation and thermal maturity evaluation. In addition, thermal maturation has significant effects on some light hydrocarbon parameters. The LNDF method can effectively avoid evaporative loss to reveal the original geochemical information of light hydrocarbons.

Experimental study on the relationships between composition distribution and laminar flame speed of pyrolysis products

Experiments are performed to determine the effects of composition distribution on the laminar flame speeds of various pyrolysis products. The compositions of the pyrolysis gases are found to be the same, with hydrogen, methane, and ethylene comprising the majority. However, the compositions of the pyrolysis liquids are quite different under various cracking conditions. The C10–C12 cycloalkanes and alkanes account for the majority of the composition when the conversion rate is relatively low (≤0.072), while the C6–C8 aromatics and alkenes gradually become the dominant species with an increase in the conversion rate. Experimental results show that the laminar flame speeds of different pyrolysis gases (or different pyrolysis liquids) have a few discrepancies, although the pyrolysis conditions are quite different. However, the laminar flame speeds of different pyrolysis products show significant differences, which are found to be related to both the pyrolysis gas content and the properties of the pyrolysis liquids.

Strain-modulated electronic transport in two-dimensional carbon allotropes

Carbon has various allotropes showing rich physical properties. Here, we take net C and net W as the research objects. They are all composed of carbonic squares C4, hexagons C6, and octagons C8, but with different compositions. Using the combination of density functional theory calculations and non-equilibrium Green’s function method, we study the significant changes in electronic structures and transport behaviors in response to external strain. For net C, tunable negative differential resistance (NDR) is observed. The NDR bias region can be moved and widened, while its peak-to-valley ratio can be increased from the original 1.14 to largest 2.67. The electrical conductivity of net W exhibits a very good linear relationship within a large strain range from −4% to +4%, and it can be increased to 219.9%. By analyzing their band structures, the effective regulations of strain on both the NDR and linear conductivity are explained. These results show not only the differences from deformation for various carbon rings under strain but also a certain guiding significance for applications in electronic devices.

First report of perfluoroalkyl acids (PFAAs) in the Indus Drainage System: Occurrence, source and environmental risk

Perfluoroalkyl acids (PFAAs) are of global interest due to their persistence in the aquatic environment. This study assessed the occurrence of PFAAs in the Indus Drainage System and discerned their potential sources and environmental risks for the first time in Pakistan. 13 perfluoroalkyl carboxylic acids (PFCAs) and 4 perfluoroalkyl sulfonates (PFSAs) were analyzed to verify the dominant prevalence of short-chain PFAAs in the environment since the phase-out of long-chain perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). A significant variation (p ≤ 0.05) of individual PFAAs between the monitoring sites was confirmed by data normality tests Kolmogorov-Smirnov and Shapiro-Wilk, suggesting that different locations contribute differently to individual PFAAs concentrations. ΣPFAAs concentrations in riverine water and sediments ranged from 2.28 to 221.75 ng/L and 0.78–29.19 ng/g dw, respectively. PFBA, PFPeA, and PFHxA were the most abundant PFAAs, and on average accounted for 14.64, 13.75, and 12.97 ng/L of ∑PFAAs in riverine water and 0.34, 0.64, and 0.79 ng/g dw of ∑PFAAs in sediments. ΣPFAAs mean contamination in the drainage was significantly (p < 0.05) high in River Chenab followed by River Indus > Soan > Ravi > Kabul > Swat with more prevalence of short-chain (C4–C7) PFCAs followed by PFOA, PFBS, PFOS, PFNA, PFDA, PFHxS, PFUnDA, and PFDoDA. The correlation analysis determined the PFAAs' fate and distribution along the drainage, indicating that PFAAs with carbon chains C4–C12, except for PFSAs with carbon chains C6–C8, were most likely contaminated by the same source, the values of Kd and Koc increased linearly with the length of the perfluoroalkyl carbon chain, better understand the transport and partitioning of individual PFAAs between riverine water and sediments, where the HCA and PCA discerned industrial/municipal wastewater discharge, agricultural and surface runoff from nearby fields, and urban localities as potential sources of PFAAs contamination. The collective mass flux of short-chain (C4–C7) PFCAs was 5x higher than that of PFOS + PFOA, suggesting a continuous shift in the production and usage of fluorinated replacements for long-chain PFAAs with short-chain homologs. In terms of risk, individual PFAAs pollution in the drainage was within the world's risk thresholds for human health, with the exception of PFBA, PFPeA, PFHpA, PFHxA, PFOA, PFNA, and PFBS, whereas for ecology, the concentrations of individual PFAAs did not exceed the ecological risk thresholds of the United States of America, Canada, European Union (EU), Italy, Australia, and New Zealand, with the exception of PFSAs, whose detected individual concentrations were significantly higher than the EU, Australian and New Zealander PFSAs guidelines of 0.002 μg/L, 0.00047 μg/L, 0.00065 μg/L, 0.00013 μg/L, and 0.00023 μg/L, respectively, which may pose chronic risks to the regional ecosystem and population.

Stable Fatty Acid Solvates of Dasatinib, a Tyrosine Kinase Inhibitor: Prediction, Process, and Physicochemical Properties.

Exploration of alternate solid forms for dasatinib, a potent oncogene tyrosine kinase inhibitor classified under Biopharmaceutics Classification System (BCS) class II drugs with low water solubility and high permeability, has been performed using COSMO-RS excess enthalpy (Hex) to increase dissolution. The theoretical prediction resulted in the potential for the formation of C6–C8 fatty acid solvates with dasatinib. A crystallization process has been identified for the preparation of the predicted solvates and successfully scaled up till the 100 g level. The fatty acid solvates are completely characterized using powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) spectroscopy, and proton nuclear magnetic resonance (1H NMR) spectroscopy. Unique powder X-ray diffraction patterns and powder indexing of C6–C8 fatty acid solvates indicate the purity of the solid phase. The red shift in the acid carbonyl stretching frequency of C6–C8 fatty acids in FT-IR spectra and the intactness of the fatty acid proton in 1H-NMR spectra provide evidence for solvate formation. The stoichiometry of active pharmaceutical ingredients (APIs) with solvent in solvates is measured using TGA and 1H-NMR spectroscopy. Dasatinib C6–C8 fatty acid solvates were found to retain their solid form under various stress and pharmaceutical processing conditions. In addition, they exhibited improved powder dissolution over dasatinib Form H1-7 by 2.2-fold. They also showed stability at 40 °C and 75% RH for 3 months. C8 fatty acid is a USFDA GRAS listed solvent, and hence may be a viable option for drug product development.

Synthesis of alkylbenzenes via the alkylation of benzene using α-olefin dimers and the surfactant properties of their sulfonates

Abstract Fischer-Tropsch syncrude prepared via the Fischer-Tropsch synthesis (FTS) using a Fe-based catalyst is featured by its high content of linear α-olefins (C5–C13). The utilization of C6–C8 α-olefins for the synthesis of alkyl benzene sulfonate surfactants was performed in the present work via dimerization, benzene alkylation, and sulfonation. The effects of the reaction conditions on benzene alkylation over a trimethyl amine hydrochloride-acidic anhydrous aluminum chloride ionic liquid catalyst (Et3NHCl-AlCl3) have been studied in detail using C6 α-olefin dimers as a model alkylation agent. Under the optimal reaction conditions (molar ratio of AlCl3 to Et3NHCl = 2, catalyst loading = 0.29 mol %, reaction temperature = 30 °C, and molar ratio of benzene to C6 α-olefin dimer = 10) the conversion of the C6 α-olefin dimer was 100% and the selectivity toward the mono alkylbenzene product was 91.0%. C6–C8 α-olefin dimer alkylbenzene sulfonates (C6–C8 DBS) were synthesized via sulfonation using chlorosulfonic acid and characterized using Fourier Transform Infrared (FT-IR) spectroscopy and Liquid Chromatography–Mass Spectrometry (LC–MS). The surfactant properties of the C6–C8 DBS, including their equilibrium and dynamic surface tension, foaming, wetting and emulsifying capabilities, were closely explored and compared with a commercial linear alkylbenzene sulfonate (LAS). The limiting surface tension (γ CMC = 34.62 mN m−1) and critical micelle concentration (CMC = 2.15 mmol L−1) of C6 α-olefin dimer alkylbenzene sulfonate (C6-DBS) were similar to those of LAS. Upon increasing the hydrocarbon chain length, the γ CMC of C6-DBS, C7-DBS, and C8-DBS remained unchanged, while the CMC decreased. C6–C8-DBS exhibited foaming, emulsifying, and wetting properties comparable to LAS.

Insight into the performance of different Pt/KL catalysts for n-alkane (C6–C8) aromatization: catalytic role of zeolite channels

The weakened catalytic role of the zeolite channels might be a considerable reason for the low superiority of Pt/KL catalysts in n-octane aromatization.