Shorter Carbon Chain Length Research Articles

Esterification Reaction Kinetics of Acetic and Oleic Acids with Ethanol in the Presence of Amberlyst 15

Esterification of acetic and oleic acids with ethanol in the presence of Amberlyst 15 was evaluated as a function of reaction temperature, fatty acid-to-ethanol molar ratio, catalyst concentration, and fatty acid carbon chain length. All reactions were carried out using a batch reaction system, and the resulting experimental data was modeled using Langmuir–Hinshelwood–Hougen–Watson and Eley–Rideal surface reaction kinetic models to determine reaction rates. Esterification of acetic and oleic acid with ethanol increases with increasing reaction temperature, catalyst concentration, and fatty acid-to-alcohol molar ratio. Shorter carbon chain lengths also enhanced esterification. A maximum esterification of 67.1 and 41.6% was observed for acetic and oleic acid, respectively. Esterification of both fatty acids with ethanol in the presence of Amberlyst 15 was determined to be a surface reaction limited. The reaction rate constant (k) for acetic acid esterification was determined to be 4.31/min according to the ER model ( $$R^2 \ge 0.94$$ ), while oleic acid esterification was determined to be 0.263/min ( $$R^{2} \ge 0.79$$ ) based upon the LHHW model.

Increasing Dietary Medium-Chain Fatty Acid Ratio Mitigates High-fat Diet-Induced Non-Alcoholic Steatohepatitis by Regulating Autophagy

Previous studies have demonstrated that saturated fatty acids (SFAs) are more lipotoxic than unsaturated fatty acids (UFAs) in inhibiting hepatic autophagy and promoting non-alcoholic steatohepatitis (NASH). However, there have been few studies have investigated the effects of carbon chain length on SFA-induced autophagy impairment and lipotoxicity. To investigate whether SFAs with shorter carbon chain lengths have differential effects on hepatic autophagy and NASH development, we partially replaced lard with coconut oil to elevate the ratio of medium-chain fatty acids (MCFAs) to long-chain fatty acids (LCFAs) in a mouse high-fat diet (HFD) and fed mice for 16 weeks. In addition, we treated HepG2 cells with different combinations of fatty acids to study the mechanisms of MCFAs-mediated hepatic protections. Our results showed that increasing dietary MCFA/LCFA ratio mitigated HFD-induced Type 2 diabetes and NASH in mice. Importantly, we demonstrated that increased MCFA ratio exerted its protective effects by restoring Rubicon-suppressed autophagy. Our study suggests that the relative amount of LCFAs and MCFAs in the diet, in addition to the amount of SFAs, can significantly contribute to autophagy impairment and hepatic lipotoxicity. Collectively, we propose that increasing dietary MCFAs could be an alternative therapeutic and prevention strategy for Type 2 diabetes and NASH.

Carbon Chain Length Increase Reactions of Platform Molecules Derived from C5 and C6 Sugars

The production of liquid fuels from lignocellulose-derived platform molecules has attracted much interest in recent years. Platform molecules mostly have a shorter carbon chain length, compared to liquid fuels, which have a typical chain length varying between 4 and 25 carbon atoms, whereas aviation and especially diesel fuel have a carbon chain length exceeding 10 carbon atoms. For this reason, some carbon chain length increase reactions are required. In this article, carbon chain length increase reactions are compared for typical lignocellulose-derived platform molecules. The focus is placed on the ability of the molecules to participate in self-condensation reactions in a controlled manner. Hydrogen plays a key role when producing fuels from platform molecules. Hydrotreatment is applied not only when converting the products from a carbon chain length increase reaction into hydrocarbons but also for modifying the functional groups of the model compounds and, thereby, their reactivity.

Release and Gas-Particle Partitioning Behaviors of Short-Chain Chlorinated Paraffins (SCCPs) During the Thermal Treatment of Polyvinyl Chloride Flooring.

Chlorinated paraffin (CP) mixture is a common additive in polyvinyl chloride (PVC) products as a plasticizer and flame retardant. During the PVC plastic life cycle, intentional or incidental thermal processes inevitably cause an abrupt release of short-chain CPs (SCCPs). In this study, the thermal processing of PVC plastics was simulated by heating PVC flooring at 100-200 °C in a chamber. The 1 h thermal treatment caused the release of 1.9-10.7% of the embedded SCCPs. A developed emission model indicated that SCCP release was mainly controlled by material-gas partitioning at 100 °C. However, release control tended to be subjected to material-phase diffusion above 150 °C, especially for SCCP congeners with shorter carbon-chain lengths. A cascade impactor (NanoMoudi) was used to collect particles of different sizes and gas-phase SCCPs. The elevated temperature resulted in a higher partition of SCCPs from the gas-phase to particle-phase. SCCPs were not strongly inclined to form aerosol particles by nucleation, and less present in the Aitken mode particles. Junge-Pankow adsorption model well fitted the partitioning of SCCPs between the gas-phase and accumulation mode particles. Inhalation exposure estimation indicated that PVC processing and recycling workers could face a considerably high risk for exposure to SCCPs.

Cuticle hydrocarbons in saline aquatic beetles.

Hydrocarbons are the principal component of insect cuticle and play an important role in maintaining water balance. Cuticular impermeability could be an adaptative response to salinity and desiccation in aquatic insects; however, cuticular hydrocarbons have been poorly explored in this group and there are no previous data on saline species. We characterized cuticular hydrocarbons of adults and larvae of two saline aquatic beetles, namely Nebrioporus baeticus (Dytiscidae) and Enochrus jesusarribasi (Hydrophilidae), using a gas chromatograph coupled to a mass spectrometer. The CHC profile of adults of both species, characterized by a high abundance of branched alkanes and low of unsaturated alkenes, seems to be more similar to that of some terrestrial beetles (e.g., desert Tenebrionidae) compared with other aquatic Coleoptera (freshwater Dytiscidae). Adults of E. jesusarribasi had longer chain compounds than N. baeticus, in agreement with their higher resistance to salinity and desiccation. The more permeable cuticle of larvae was characterized by a lower diversity in compounds, shorter carbon chain length and a higher proportion of unsaturated hydrocarbons compared with that of the adults. These results suggest that osmotic stress on aquatic insects could exert a selection pressure on CHC profile similar to aridity in terrestrial species.

Environmental behaviour of short-chain chlorinated paraffins in aquatic and terrestrial ecosystems of Ny-Ålesund and London Island, Svalbard, in the Arctic

The environmental behaviour of short-chain chlorinated paraffins (SCCPs) was investigated in both aquatic and terrestrial ecosystems in the Arctic. The mean concentrations of SCCPs in the aquatic and terrestrial samples were 178.9ng/g dry weight (dw) and 157.2ng/g dw, respectively. Short carbon chain (C10) and less-chlorinated (Cl6) congener groups were predominant in the Arctic samples, accounting for 48.6% and 34.8% of the total SCCPs, respectively. The enrichment of lighter SCCP congener groups (i.e., fewer chlorine atoms with shorter carbon chain lengths) indicated that the fractionation process occurred during long-range transport. The biomagnification factor (BMF) was 0.46 from gammarid to cod, which indicated that the SCCPs did not biomagnify between these two species. The soil–vegetation bioaccumulation factor (BAF) of SCCPs was 29.9, and C13 and Cl7, 8 congener groups tended to accumulate in the terrestrial vegetation. Regression analysis (BAFs=10.9×#C+5.6×#Cl−125.2, R=0.53, P<0.01) showed that the number of carbon and chlorine atoms influenced the bioaccumulative behaviour of SCCPs and suggested that the number of carbon atoms had a greater influence on the BAFs of SCCPs in the terrestrial ecosystem than did the number of chlorine atoms.

Photoluminescence and self-assembly of cesium lead halide perovskite nanocrystals: Effects of chain length of organic amines and reaction temperature

All-inorganic halide perovskites have become one of the most prospective materials for lightening and display technology due to their color-tunable and narrow-band emission. Herein, we have systematically studied the effects of organic amines with different hydrocarbon chain length on the optical properties and morphology as well as the crystal structure of colloidal CsPbBr3 nanocrystals (NCs), which were synthesized in the presence of oleic acid (OA) and organic amines by using a simple hot-injection approach. The hydrocarbon chain length has shown an independent correlation to the morphology and crystal structure of the as-obtained CsPbBr3 NCs at 160°C, but their optical properties can be affected to some extent. The photoluminescence quantum yields (PLQYs) of the CsPbBr3 NCs synthesized in the presence of organic amines with long carbon chain length are generally in the range of 55–80% for different reaction time, but the PLQYs of less than 20% are obtained for the products synthesized in the presence of octylamine (OTAm) with short carbon chain length. The effects of the reaction temperature on the optical properties, size and crystal structure of the CsPbBr3 NCs synthesized in the presence of cetylamine (CTAm) are studied. Interestingly, some nanoplates also appear in these CsPbBr3 NCs obtained at relatively low temperatures (120 and 140°C), which have a strong tendency to self-assemble into face-to-face nanostructures. Such a similar self-assembly behavior is also observed in the product synthesized in the presence of oleylamine (OLAm), but only flat nanoplates are observed in the products in the presence of OTAm at 120°C. The results indicate that the lower reaction temperature and hydrocarbon chain length of the organic ligands play a significant role in the self-assembly of CsPbBr3 NCs. This work opens up an alternative approach to controllable-synthesis of perovskite NCs through varying the carbon chain length of organic surfactants, and enlightens the fabrication of different nanostructures via self-assembly methods for further optoelectronic applications.

Short-chain chlorinated paraffins in soil, paddy seeds (Oryza sativa) and snails (Ampullariidae) in an e-waste dismantling area in China: Homologue group pattern, spatial distribution and risk assessment

Short-chain chlorinated paraffins (SCCPs) in multi-environmental matrices are studied in Taizhou, Zhejiang Province, China, which is a notorious e-waste dismantling area. The investigated matrices consist of paddy field soil, paddy seeds (Oryza sativa, separated into hulls and rice unpolished) and apple snails (Ampullariidae, inhabiting the paddy fields). The sampling area covered a 65-km radius around the contamination center. C10 and C11 are the two predominant homologue groups in the area, accounting for about 35.7% and 33.0% of total SCCPs, respectively. SCCPs in snails and hulls are generally higher than in soil samples (30.4–530 ng/g dw), and SCCPs in hulls are approximate five times higher than in corresponding rice samples (4.90–55.1 ng/g dw). Homologue pattern analysis indicates that paddy seeds (both hull and rice) tend to accumulate relatively high volatile SCCP homologues, especially the ones with shorter carbon chain length, while snails tend to accumulate relatively high lipophilic homologues, especially the ones with more substituted chlorines. SCCPs in both paddy seeds and snails are linearly related to those in the soil. The e-waste dismantling area, which covers a radius of approximate 20 km, shows higher pollution levels for SCCPs according to their spatial distribution in four matrices. The preliminary assessment indicates that SCCP levels in local soils pose no significant ecological risk for soil dwelling organisms, but higher risks from dietary exposure of SCCPs are suspected for people living in e-waste dismantling area.

Ionic liquid hybrids: Progress toward non-corrosive electrolytes with high-voltage oxidation stability for magnesium-ion based batteries

Magnesium – ion batteries have the potential for high energy density but require new types of electrolytes for practical application. Ionic liquid (IL) electrolytes offer the opportunity for increased safety and broader voltage windows relative to traditional electrolytes. We present here a systematic study of both the conductivity and oxidative stability of hybrid electrolytes consisting of eleven ILs mixed with dipropylene glycol dimethylether (DPGDME) or acetonitrile (ACN) cosolvents and magnesium bis(trifluoromethylsulfonyl)imide (Mg(TFSI)2). Our study finds a correlation of higher conductivity of ILs with unsaturated rings and short carbon chain lengths, but by contrast, these ILs also exhibited lower oxidation voltage limits. For the cosolvent additive, although glymes have a demonstrated capability of coordination with Mg2+ ions, a decrease in conductivity compared to acetonitrile hybrid electrolytes was observed. When cycled within the appropriate voltage range, the IL-hybrid electrolytes that show the highest conductivity provide the best cathode magnesiation current densities and lowest polarization as demonstrated with a Mg0.15MnO2 and Mg0.07V2O5 cathodes.

High-Resolution Live-Cell Imaging and Analysis by Laser Desorption/Ionization Droplet Delivery Mass Spectrometry.

We have developed a new ambient-ionization mass spectrometric technique named laser desorption/ionization droplet delivery mass spectrometry (LDIDD-MS). LDIDD-MS permits high-resolution, high-sensitivity imaging of tissue samples as well as measurements of both single-cell apoptosis and live-cell exocytosis. A pulsed (15 Hz) UV laser beam (266 nm) is focused on a surface covered with target analytes to trigger their desorption and ionization. A spray of liquid droplets is simultaneously directed onto the laser-focused surface region to capture the ionized analytes and deliver them to a mass spectrometer. The approach of rapid and effective capturing of molecules after laser desorption/ionization allows the limit of detection for the amino acid lysine to be as low as 2 amol under ambient ionization conditions. Two-dimensional maps of the desorbed/ionized species are recorded by moving the sample on an XY translational stage. The spatial resolution for imaging with LDIDD-MS was determined to be 2.4 μm for an ink-printed pattern and 3 μm for mouse brain tissue. We applied LDIDD-MS to single-cell analysis of apoptotic HEK cells. Differences were observed in the profiles of fatty acids and lipids between healthy HEK cells and those undergoing apoptosis. We observed upregulation of phosphatidylcholine (PC) with a relatively shorter carbon chain length and downregulation of PC with a relatively longer carbon chain length. We also applied LDIDD-MS for a real-time direct measurements of live-cell exocytosis. The catecholamine dopamine and trace amines (phenethylamine and tyramine) were detected from live PC12 cells without damaging them.

Performance enhancement of vertically aligned carbon nanotube membranes for separation of binary mixtures of H2S/CH4 using different amine groups

Synthesis and performance evaluation of vertically aligned carbon nanotube membranes functionalized with different amine groups in order to separate H2S from binary mixtures of H2S/CH4 were experimentally studied. For increasing the performance of the membrane, it was functionalized with butylamine, sec-butylamine, dodecylamine and octadecylamine. The effect of using linear amine groups with different carbon chain length and branched amine on increase of H2S permeability and selectivity of membrane was studied. The results showed that using linear amine with shorter carbon chain length is preferred to other amine groups, and the membrane functionalized with butylamine has the maximum selectivity and permeation values for the H2S. These values are reported to be 2.98 and 2.3 times those of obtained for the membrane with no functional group. The results also reveal that diffusivity of a N2 single gas is 3.22 and 1.72 times of Knudsen’s diffusion before and after functionalization, respectively.

Stirring-induced growth of hierarchical Cu structures in the presence of diamine

We propose a novel strategy for the synthesis of materials with a hierarchical structure. This strategy is based on in situ combination of two processes, namely, capping agent-mediated oriented growth and stirring-induced aggregation, and the growth of Cu crystals in the presence of linear alkyl diamines of short carbon chain length under vigorous stirring is shown to demonstrate its feasibility. Our experimental results have shown that the oriented growth of Cu nanowires can be significantly disturbed by vigorous stirring, resulting in large-scale growth of hierarchical dendritic Cu crystals. The morphology of grown dendritic Cu crystals has been found to vary with the stirring rate, type of diamine, and diamine concentration, which makes it possible to prepare hierarchical Cu structures of various morphologies. The growth mechanism of these hierarchical Cu structures is proposed based on the experimental observations. The present unique strategy offers a fresh way to fabricate materials with a hierarchical structure.

Characterisation of an l-Haloacid Dehalogenase from the Marine Psychrophile Psychromonas ingrahamii with Potential Industrial Application

The recombinant L-haloacid dehalogenase from the marine bacterium Psychromonas ingrahamii has been cloned and over-expressed in Escherichia coli. It shows activity towards monobromoacetic (100 %), monochloroacetic acid (62 %), S-chloropropionic acid (42 %), S-bromopropionic acid (31 %), dichloroacetic acid (28 %) and 2-chlorobutyric acid (10 %), respectively. The L-haloacid dehalogenase has highest activity towards substrates with shorter carbon chain lengths (≤ C3), without preference towards a chlorine or bromine at the α-carbon position. Despite being isolated from a psychrophilic bacterium, the enzyme has mesophilic properties with an optimal temperature for activity of 45 °C. It retains above 70 % of its activity after being incubated at 65 °C for 90 min before being assayed at 25 °C. The enzyme is relatively stable in organic solvents as demonstrated by activity and thermal shift analysis. The V max and K m were calculated to be 0.6 μM min(-1) mg(-1) and 1.36 mM with monobromoacetic acid, respectively. This solvent-resistant and stable L-haloacid dehalogenase from P. ingrahamii has potential to be used as a biocatalyst in industrial processes.

Synthesis of pore-variable mesoporous CdS and evaluation of its photocatalytic activity in degrading methylene blue

In this study, mesoporous CdS polycrystallites have been synthesized using aliphatic acids of hexanoic acid, octanoic acid, and oleic acid as coordinating and capping agents, respectively. The fibrous Cd–fatty acid salts act as a template to form the tubular CdS. The organic species are found to be necessary for maintaining the network of mesoporous CdS. The characterization results indicate that the shorter carbon chain length in aliphatic acids favors the wurtzite phase and particle size growth the specific surface area, pore diameter and pore volume show a monotonic raise with increasing carbon chain. The photocatalytic activities of mesoporous CdS tubes exhibit much higher efficiency than those of nanosized CdS powders in decolorizing methylene blue under simulated visible light.

In vitro toxicological characterization of perfluorinated carboxylic acids with different carbon chain lengths

Perfluorooctanoic acid (PFOA) is in use for the production of fluoropolymers (PFT). Due to its toxic properties it was proposed to replace the substance in its industrial applications by homologous compounds with shorter carbon chain length that were supposed to be less toxic compared to PFOA, however, the smaller PFOA homologs are poorly characterized so far. In this study we have conducted a comparative analysis of the toxicity of perfluorinated carboxylic acids (PFCA) with a carbon chain length ranging from four to twelve carbon atoms. By using the human hepatocarcinoma cell line HepG2 as an in vitro model for human hepatocytes we could show a positive correlation between the carbon chain length of the respective PFCA and its cytotoxicity. There was, however, no indication of an apoptotic mechanism for cytotoxicity. All PFCA under investigation were negative in two independent genotoxicity assays. As PFOA, being a well-known peroxisome proliferator, the other PFCA tested in this study were also shown to activate human peroxisome proliferator-activated receptor alpha (PPARα) with PFOA having the highest potential of PPARα activation. Moreover, the compounds showed weak potential to activate PPARγ and hardly activated PPARδ. Taken together, the in vitro study revealed that PFCA with a shorter carbon chain length seem to be less toxic than PFOA.

Highly efficient and well-resolved Mn2+ ion emission in MnS/ZnS/CdS quantum dots

We demonstrate a strategy for the growth of Mn2+ ion doped cadmium based II–VI semiconductor quantum dots (QDs) with a designed buffer layer of ZnS (MnS/ZnS/CdS or Mn:CdS QDs), which aims to meet the challenge of obtaining highly efficient and well-resolved Mn2+ ion emission. First, small, high quality MnS cores are obtained by using thiols to replace conventional alkyl amines as capping ligands. Then a buffer layer of ZnS with a tailored thickness is introduced to the QDs before the growth of CdS shells to reduce the size mismatch between the Mn2+ (dopant) and Cd2+ (host) ions. The fabricated MnS/ZnS/CdS core/shell QDs exhibit a high PL QY of up to 68%, which is the highest ever reported for any type of Mn2+ ion doped cadmium based II–VI semiconductor QD. The photoluminescence (PL) of the QDs consists of well-resolved Mn2+ ion emission without any detectable emission from the CdS band edge or surface defects. In addition, our MnS/ZnS/CdS QDs cannot only be made water-soluble, but can also be coated by ligands with short carbon chain lengths, nearly without cost to the PL QY, which could make them strong candidates for practical applications in biology/biomedicine and opto/electronic devices.

The effect of the addition of individual methyl esters on the combustion and emissions of ethanol and butanol -diesel blends

Biodiesel fuel is known to improve the properties of alcohol-diesel blends for use in compression ignition engines. In this work the effects on combustion characteristics and emissions of preselected methyl esters (i.e. biodiesel components) have been assessed. The most representative individual fatty acid methyl esters (FAMEs) were added to alcohol blends in order to understand the effect of carbon chain length and degree of unsaturation on combustion and emissions. The effects of alcohol addition on the properties of fuel blends were also investigated using ethanol and butanol. Relating to the physical properties, emphasis was given to both stability and lubricity of alcohol-diesel blends. The results showed that 15% of all methyl esters was enough to avoid phase separation of alcohol-diesel blends and keep the wear scar diameter of the blends below the limitation required by the lubricity standard. For combustion, the use of alcohol blends shows a clear benefit in terms of CO and soot emissions with respect to biodiesel blends with the same oxygen content. Short carbon chain length and saturated methyl esters are recommended to improve alcohol blends. Comparisons between the alcohols, show that butanol rather than ethanol produces lower CO, THC and soot emissions.

Properties of the Quaternary Ammonium Salts with Novel Counterions

AbstractThe Krafft temperatures, surface tensions and bacteriostatic efficacies of a series of dodecyl/tetradecyltrimethylammonium salts with new type counterions based on the general formula RN+(CH3)3 A− were measured. The results revealed that the Krafft temperatures of the studied products were below 0 °C and the surface tensions of water were decreased to 22–42 mN m−1 when applying these surfactants at a concentration range from 10−2 to 10−4 mol L−1. Moreover, the physicochemical parameters such as the saturation adsorption value, the minimum area per surfactant molecule and the standard thermodynamic parameters of adsorption and micellization varied with different counterions for these prepared quaternary ammonium salts. In addition, the bacteriostatic tests showed that the counterions with shorter carbon chain lengths were associated with greater efficacy for the novel quaternary ammonium salts studied here.

Ignition Quality of Biodiesel from Cottonseed and Soybean Oil

The thermal analysis has been employed to yield information on the biodiesel ignition quality since the ignition quality influences the combustion and exhaust emissions of the fuels in a compression ignition (CI) engine. The chemical compositions of -10 petrodiesel (-10PD), soybean-based biodiesel (SME) and cottonseed-based biodiesel (CME) are analyzed by gas chromatography-mass spectrometry (GC-MS). Ignition temperature of -10PD, SME and CME is determined by thermogravimetry-differential scanning calorimetry (TG-DSC). The study shows that the biodiesel is mainly composed of fatty acid methyl esters: C14:0–C24:0, C16:1–C22:1, C18:2 and C18:3. Biodiesel ignition quality is better than petrodiesel. The ignition temperature of CME and SME is 207.4 and 213.9 °C respectively. The ignition quality of biodiesel is better with shorter carbon chain lengths and more saturated fatty acid methyl ester (SFAME).

Liquid-crystalline oxovanadium(IV) complexes accessed from bidentate [N, O] donor salicylaldimine Schiff-base ligands

A series of bis[4-(n-alkoxy)-N-(4′-R-phenyl)salicylideneiminato]oxovanadium(IV) complexes (n = 6, 10, 14, 16, 18 and R = C3H7) were prepared and their mesogenic properties were investigated. The mesomorphic behaviors of the compounds were studied by polarized optical microscopy and differential scanning calorimetry. Ligands display SmA/SmC and unexpected nematic mesophases. The complexes bearing longer alkoxy carbon chain (n = 10, 14, 16, and 18) showed both monotropic or enantiotropic transitions with smectic A and high ordered smectic E phases. However, the complex with shorter carbon chain length (n = 6) showed monotropic transition with an unprecedented nematic (N) phase. A density functional theory study was carried out using DMol3 at BLYP/DNP level to obtain a stable optimized structure. A square-pyramidal geometry for the vanadyl complexes has been suggested. A νV=O stretching value of ∼970 cm−1 corroborated absence of any V = O ··· V = O interactions. Cyclic voltammetry revealed a quasireversible one-electron response at 0.61 V for the VO(IV)–VO(V) redox couple. Variable temperature magnetic susceptibility measurements of the vanadyl complexes suggested absence of any exchange interactions among the vanadyl spin centers.