Early Reaction Times Research Articles

Heterogeneous Char Based Solid Acid Catalysts from Brown Bin Waste to Create a Green Process for the Production of Butyl Butyrate

Brown bin waste can be used for the production of butanol and butyric acid by employing fermentation techniques. This study focuses on heterogeneous solid acid catalyst obtained from solid residues derived from a fermentation process and applied for the efficient conversion of butyric acid to butyl butyrate. The solid acid catalysts were produced by sulfonation of char obtained from the slow pyrolysis of brown bin waste digestate at various temperatures (400, 500 and 600 °C). The catalysts possessing the highest surface area and acid density were shown to have the highest catalytic activity and thus performed better giving competitive results to Amberlyst 15 and H2SO4 (96 % yield), after 24 h reaction. Increasing the catalyst loading was found to positively affect the yields of butyl butyrate, especially at early reaction time. Realistic kinetic parameters were formulated for the optimum char based solid acid catalyst using two power law models.

Mechanistic Study of Ni/CeO2‐catalyzed CO2/CH4 Reaction Using Flow and Static Methods

Ni/CeO2 catalysts with different Ni loadings (5, 7, 10, 12, and 14 wt% Ni) were prepared by an impregnation method and examined for the CO2 reforming of methane using flow and static reactors. Their catalytic activities and selectivities were measured under CO2/CH4/Ar (=5/5/40 cm3/min) flow at 450–800°C using a flow reactor system with an on‐line gas chromatography. At fixed temperature, the CO2 and CH4 conversions varied only slightly with the Ni wt%, whereas the H2/CO ratio increased with increasing Ni wt%. The conversions increased with temperature, reaching 98% at 800°C. The H2/CO ratio varied with temperature in the range of 450–800°C, from less than 1 below 550°C to close to 1 at 550–600°C and then back to less than 1 above 600°C. The apparent activation energies were determined to be 43.1 kJ/mol for the CO2 consumption and 50.2 kJ/mol for the CH4 consumption based on the rates measured for the reforming reaction over 5 wt% Ni/CeO2 catalyst at 550–750°C. Additionally, the catalytic reforming reaction at low pressure (40 Torr) was investigated by a static reactor system by using a differential photoacoustic cell, in which the rates were measured from the CO2 photoacoustic signal data at early reaction times over the temperature range of 460–610°C. Apparent activation energies of 25.5–30.1 kJ/mol were calculated from the CO2 disappearance rates. The CO2 adsorption on the Ni/CeO2 catalyst was investigated by the CO2 photoacoustic spectroscopy and Fourier transform infrared spectroscopy. Feasible side reactions during the catalytic CO2/CH4 reaction were suggested on the basis of the kinetic and spectroscopic results.

Alkali-activated slag cements produced with a blended sodium carbonate/sodium silicate activator

An alkali-activated slag cement produced with a blend of sodium carbonate/sodium silicate activator was characterised. This binder hardened within 12 h and achieved a compressive strength of 20 MPa after 24 h of curing under ambient conditions, which is associated with the formation of an aluminium substituted calcium silicate hydrate as the main reaction product. Carbonates including pirssonite, vaterite, aragonite and calcite were identified along with the zeolites hydroxysodalite and analcime at early times of reaction. The partial substitution of sodium carbonate by sodium silicate reduces the concentration of carbonate ions in the pore solution, increasing the alkalinity of the system compared with a solely carbonate-activated paste, accelerating the kinetics of reaction and supplying additional silicate species to react with the calcium dissolving from the slag as the reaction proceeds. These results demonstrate that this blend of activators can be used effectively for the production of high-strength alkali-activated slag cements, with a microstructure comparable to what has been identified in aged sodium-carbonate-activated slag cements but without the extended setting time reaction usually identified when using this salt as an alkali activator.

Sports Physical Therapy Section Poster Presentations (Abstracts SPO1–SPO119)

Sports Physical Therapy Section Poster Presentations (Abstracts SPO1–SPO119)

Continuous production of pure maltodextrin from cyclodextrin using immobilized Pyrococcus furiosus thermostable amylase

Maltodextrin in specific length is of great interest because of its wide industrial applications. Previously, we have proven that Pyrococcus furiosus thermostable amylase (PFTA) produces high purity maltoheptaose (G7) from β-cyclodextrin (CD) at early reaction time. In this study, an optimal continuous process for pure maltodextrin production from CDs using PFTA with immobilization in a packed-bed reactor (PBR) was developed. For testing PBR, β-CD was used as a substrate to produce G7. The activity of immobilized PFTA in PBR retained 85% of the initial activity after 6 cycles, and the product purity was unchanged. The optimal conditions for the maximized G7-purity of 96.3% were predicted at 4.7mL/min of flow, 1.1% substrate and 48.7°C. Maltohexaose and maltooctaose, 92% and 97% purity respectively, were produced from CDs at the similar condition as well. Through this study, we successfully demonstrated the possibility of large-scale continuous production of pure maltodextrins from CDs.

Investigation of the Relationship between CO2 Reservoir Rock Property Change and the Surface Roughness Change Originating from the Supercritical CO2-Sandstone-groundwater Geochemical Reaction at CO2 Sequestration Condition

Laboratory experiments were performed to investigate the property change of sandstones, resulting from scCO2-rock-groundwater reaction for 150 days under CO2 sequestration conditions. The average surface roughness value (SRrms) increased more than 3.5 times during early 90 days, suggesting that the weathering process of sandstone occurs in the early reaction time after CO2 injection. The average porosity of sandstones increased by 8.8% and P wave velocity decreased by 5.7%. The trend of rock property change and SRrms change showed in a logarithmic manner, indicating that the physical property change of reservoir rocks directly comes from CO2 related geochemical reaction.

Kinetic studies of the infrared-induced reaction between atomic chlorine and solid parahydrogen

We present Fourier-transform infrared (FTIR) spectroscopic studies of the IR-induced Cl+H2(v=1)→HCl+H reaction in a parahydrogen (pH2) matrix aimed at distinguishing between two proposed reactions mechanisms; direct-IR and vibron-mediated. The Cl atom reactants are produced via 355nm in situ photolysis of a Cl2 doped pH2 matrix. After photolysis is complete, a long-pass IR filter in the FTIR beam is removed and we measure the ensuing IR-induced reaction kinetics using rapid scan FTIR spectroscopy. We follow both the decay of the Cl atom reactant and growth of the HCl product using the Cl spin–orbit (SO)+Q1(0) and HCl R1(0) transitions, respectively. We show the IR-induced reaction mechanism depends on the spectral profile of the IR radiation; for IR spectral profiles that have significant IR intensities between 4000 and 5000cm−1 we observe first-order kinetics that are assigned to a vibron-mediated mechanism and for spectral profiles that have significant IR intensities that include the Cl SO+Q1(0) transition near 5094cm−1 we observe bi-exponential kinetics that are dominated by the direct-IR mechanism at early reaction times. We can distinguish between the two mechanisms using the observed kinetics. We investigate the reaction kinetics for different FTIR optical setups, for a range of sample conditions, and start and stop the IR-induced reaction to investigate the importance of secondary H atom reactions. We also study the IR-induced reaction in Br/Cl co-doped pH2 samples and show the presence of the Br atom quenches the vibron-mediated reaction kinetics presumably because the Br-atoms serve as efficient vibron traps. This paper indicates that in a highly enriched pH2 matrix the H atoms that are produced by the IR-induced Cl atom reaction likely do not play a significant role in the measured reaction kinetics which implies these secondary H atom reactions are highly selective.

The relationship between driving simulation performance and obstructive sleep apnoea risk, daytime sleepiness, obesity and road traffic accident history of commercial drivers in Turkey.

Driving performance is known to be very sensitive to cognitive-psychomotor impairment. The aim of the study was to determine the relationship between obesity, risk of obstructive sleep apnoea (OSA), daytime sleepiness, history of road traffic accident (RTA) and performance on a driving simulator, among commercial drivers. We examined commercial vehicle drivers admitted to Psycho-Technical Assessment System (PTAS), which is a computer-aided system that includes a driving simulator test and tests assessing psychomotor-cognitive skills required for driving. Risk of OSA and daytime sleepiness were assessed by the Berlin Questionnaire and the Epworth Sleepiness Scale (ESS), respectively. A total of 282 commercial vehicle drivers were consecutively enrolled. The age range was 29-76 years. Thirty drivers were at high risk of OSA. Median ESS of the group was 2 (0-20). Forty-seven percent of the subjects at high risk of OSA failed in early reaction time test, while 28% of the drivers with low risk of OSA failed (p = 0.03). The obese drivers failed the peripheral vision test when compared with non-obese drivers (p = 0.02). ESS was higher for drivers with a history of RTA when compared to those without RTA (p = 0.02). Cognitive-psychomotor functions can be impaired in obese and high risk of OSA patients. In our opinion, requiring obese and/or high risk of OSA drivers to take PTAS tests that assess driving skills and psychomotor-cognitive functions crucial to those skills would significantly improve road traffic safety, which is of considerable importance to public health.

Evolution of Coke Deposit and Its Effect on Product Selectivity for Methanol-to-Olefin Reaction in Fluidized Bed

The coke deposition on the catalyst is known to be crucial to the methanol-to-olefin conversion reaction. The effect of coke deposition level on the product selectivity for a SAPO-34-containing catalyst was investigated. The test results obtained from a fluidized bed reactor indicated that ethylene selectivity increased faster than that of propylene with increasing coke deposition up to about 6 wt % whereas the selectivity to butenes decreased. The combined selectivity of ethylene plus propylene peaked to 74% when the total coke level accumulated on the working catalyst reached 6.3 wt % at which stage methanol conversion of 99.4% and minimum coking rate of 1.4 wt % were also recorded. The coke species deposited on the catalyst continued to evolve with increasing reaction time. Carbons of alkyl types dominated in early reaction time with minor amount of aromatic carbons. As reaction progressed, more cokes of aromatic in nature were formed as evidenced by the NMR results. Methanol conversion and olefin selectivity began to decline more significantly with increasing aromatic hydrocarbon deposition on the working catalyst.

On the role of Pb0 atoms on the nucleation and growth of PbSe and PbTe nanoparticles

In this contribution, a nucleation and growth mechanism of PbSe and PbTe nanoparticles are proposed. The formation and growth of PbSe and PbTe nanoparticles during their reaction synthesis were studied and followed using transmission electron microscopy, and their related techniques. In the synthesis method, trioctylphosphine-selenide and telluride were used as the chalcogen precursors, while lead oleate was employed as the lead precursor. Different synthesis conditions were tested to assess the effect of varying the reaction time, lead to chalcogen ratio, reaction temperature, and lead oleate concentration. The synthesized nanoparticles were characterized by means of electron diffraction, energy dispersive X-ray spectroscopy, scanning transmission electron microscopy, and electron energy loss spectroscopy, to obtain information related to their morphology, crystal structure, and composition. The experimental results suggest that the growth of the lead chalcogenide nanoparticles greatly relies on the reduction of Pb2+ ions to Pb0 atoms at early reaction times; this reduction of the lead precursor is evidenced by the formation of Pb nanoparticles with sizes between 1 and 3 nm under certain synthesis conditions. These Pb nanoparticles gradually disappear as the reaction progresses, suggesting that the reduced Pb0 atoms are able to contribute to the growth of the PbSe and PbTe nanoparticles, reaching sizes between 8 and 18 nm. The current results contribute to a better understanding of the nucleation and growth mechanisms of lead chalcogenide nanoparticles, which will enable the definition of more efficient synthesis routes of these types of nanostructures.

Sustainable Solvent Systems for Use in Tandem Carbohydrate Dehydration Hydrogenation

Monophasic separation-friendly solvent systems were investigated for the sustainable acid-catalyzed dehydration of fructose to 5-hydroxymethylfurfural (HMF). The HMF selectivity depends on both fructose conversion, temperature, and the amount of cosolvent present in the aqueous solvent mixture. Use of HMF-derived 2,5-(dihydroxymethyl)tetrahydrofuran (DHMTHF) or low-boiling tetrahydrofuran (THF) as co-solvents results in increased selectivity (>70%) to HMF at fructose conversions of ca. 80%. Analysis of the fructose tautomer distribution in each solvent system by 13C NMR revealed higher furanose fractions in the presence of these and other protic (tetrahydrofurfuryl alcohol) and polar aprotic co-solvents (DMSO) relative to water alone. Formation of fructosides and/or difructose anhydrides in the presence of the co-solvents causes lower selectivity at early reaction times, but reversion to fructose and dehydration to HMF at longer reaction times results in increasing HMF selectivity with fructose conversion...

Alkane Dehydrogenation by C–H Activation at Iridium(III)

Stoichiometric alkane dehydrogenation utilizing an IrIII pincer complex, (dmPhebox)Ir(OAc)2(OH2) (1a), has been described. The reaction between 1a and octane resulted in quantitative formation of (dmPhebox)Ir(OAc)(H) (3a) and octene. At early reaction times 1-octene is the major product, indicative of terminal C–H activation by 1a. In contrast to prior reports of alkane dehydrogenation with Ir, C–H bond activation occurs at IrIII and the dehydrogenation is not inhibited by nitrogen, olefin, or water.

Effects of organic ligands on supercritical CO2-induced phlogopite dissolution and secondary mineral formation

To evaluate the long-term and short-term risks associated with geologic CO2 sequestration (GCS), we need to understand both the reactions at supercritical CO2 (scCO2)–saline water–rock interfaces, and the environmental factors affecting these interactions. This research investigated the effects of four organic ligands—oxalate, malonate, acetate, and propionate—on the dissolution and surface morphological changes of phlogopite [KMg2.87Si3.07Al1.23O10(F,OH)2] under GCS conditions (95°C and 102atm). Phlogopite was chosen as a model clay mineral in potential GCS sites. After CO2 injection, the dissolution of CO2 should cause a decrease in saline water pH, increasing phlogopite dissolution. This effect can be lessened by the buffering capacity of organic ligands. However, in this study, the ligands that formed strong complexes with surface metals (i.e., oxalate) caused phlogopite dissolution rates to increase via ligand-promoted dissolution, although the pH increased. The experimentally observed dissolution rates of phlogopite were in the order of: oxalate>malonate>acetate≈propionate. In addition, based on results from ion chromatography, oxalate and malonate concentrations were stable in our reaction systems; however, aqueous acetate and propionate concentrations continuously decreased due to solvent extraction of acetic acid and propionic acid by scCO2 at 95°C and 102atm. After 159h, all of the acetate and propionate were removed from aqueous solutions. Although the aqueous species in the bulk solution were not supersaturated with respect to potential secondary mineral phases, interestingly, in the presence of oxalate, nanoscale precipitation of amorphous silica and fibrous illite was observed at the phlogopite surface only 3h after CO2 injection. At this early reaction time, illite fibers formed a connected, hexagonal framework on phlogopite basal surfaces, but at a later reaction time, these structures detached from the surface and triggered the formation of dissolution channels. In addition, kaolinite, boehmite, diaspore, and gibbsite were identified as secondary mineral phases. These results provide new information towards understanding organic species' interactions at scCO2–saline water–rock interfaces in deep saline aquifers.

Facile hydrothermal fabrication of hollow hexagonal hydroxyapatite prisms

Well-defined hollow hexagonal prisms of hydroxyapatite (Ca10(PO4)6(OH)2) have been grown facilely on an aluminium oxide anodisc membranevia a hydrothermal reaction of calcium carbonate and phosphoric acid for 6 h at 170 °C in the presence of hydrazine monohydrate in a Teflon-lined autoclave. The sizes and the structures of calcium phosphate crystals are dependent widely on the temperature and the time of the reaction, revealing the formation mechanism of the hollow hexagonal hydroxyapatite prisms. Fourier transform infrared spectra and microscopic images show that irregular nanorods of octacalcium phosphate (Ca8H2(PO4)6·5H2O) formed in the early reaction time transform into hollow hexagonal prisms of hydroxyapatite as the reaction time goes by.

Cortical Correlates of Fitts’ Law

Fitts’ law describes the fundamental trade-off between movement accuracy and speed: it states that the duration of reaching movements is a function of target size (TS) and distance. While Fitts’ law has been extensively studied in ergonomics and has guided the design of human–computer interfaces, there have been few studies on its neuronal correlates. To elucidate sensorimotor cortical activity underlying Fitts’ law, we implanted two monkeys with multielectrode arrays in the primary motor (M1) and primary somatosensory (S1) cortices. The monkeys performed reaches with a joystick-controlled cursor toward targets of different size. The reaction time (RT), movement time, and movement velocity changed with TS, and M1 and S1 activity reflected these changes. Moreover, modifications of cortical activity could not be explained by changes of movement parameters alone, but required TS as an additional parameter. Neuronal representation of TS was especially prominent during the early RT period where it influenced the slope of the firing rate rise preceding movement initiation. During the movement period, cortical activity was correlated with movement velocity. Neural decoders were applied to simultaneously decode TS and motor parameters from cortical modulations. We suggest that sensorimotor cortex activity reflects the characteristics of both the movement and the target. Classifiers that extract these parameters from cortical ensembles could improve neuroprosthetic control.

Phosphoinositides Function Asymmetrically for Membrane Fusion, Promoting Tethering and 3Q-SNARE Subcomplex Assembly

Phosphatidylinositol 3-phosphate (PI(3)P) and phosphatidylinositol 4,5-bisphosphate (PI(4,5)P(2)) are essential for rapid SNARE-dependent fusion of yeast vacuoles and other organelles. These phosphoinositides also regulate the fusion of reconstituted proteoliposomes. The reconstituted reaction allows separate analysis of phosphoinositide-responsive subreactions: fusion with SNAREs alone, with the addition of the HOPS tethering factor, and with the further addition of the SNARE complex disassembly chaperones Sec17p and Sec18p. Using assays of membrane tethering, trans-SNARE pairing, and lipid mixing, we found that PI(3)P and PI(4,5)P(2) have distinct functions that are asymmetric with respect to R-SNARE (Nyv1p) and the 3Q-SNAREs (Vam3p, Vti1p, and Vam7p). Fusion reactions with the Q-SNAREs and R-SNARE on separate membranes showed that PI(3)P has two distinct functions. PI(3)P on Q-SNARE proteoliposomes promoted Vam7p binding and association with the other two Q-SNAREs. PI(3)P on R-SNARE proteoliposomes was recognized by the PX domain of Vam7p on Q-SNARE proteoliposomes to promote tethering, although this function could be supplanted by the tethering activity of HOPS. PI(4,5)P(2) stimulated fusion when it was on R-SNARE proteoliposomes, apposed to Q-SNARE proteoliposomes bearing PI(3)P. These functions are essential for the phosphoinositide-dependent synergy between HOPS and Sec17p/Sec18p in promoting rapid fusion.

Bovine Serum Albumin-Catalyzed Deprotonation of [1-13C]Glycolaldehyde: Protein Reactivity toward Deprotonation of the α-Hydroxy α-Carbonyl Carbon

Bovine serum albumin (BSA) in D(2)O at 25 degrees C and pD 7.0 was found to catalyze the deuterium exchange reactions of [1-(13)C]glycolaldehyde ([1-(13)C]GA) to form [1-(13)C,2-(2)H]GA and [1-(13)C,2,2-di-(2)H]GA. The formation of [1-(13)C,2-(2)H]GA and [1-(13)C,2,2-di-(2)H]GA in a total yield of 51 +/- 3% was observed at early reaction times, and at later times, [1-(13)C,2-(2)H]GA was found to undergo BSA-catalyzed conversion to [1-(13)C,2,2-di-(2)H]GA. The overall second-order rate constant for these deuterium exchange reactions [(k(E))(P)] equals 0.25 M(-1) s(-1). By comparison, (k(E))(P) values of 0.04 M(-1) s(-1) [Go, M. K., Amyes, T. L., and Richard, J. P. (2009) Biochemistry 48, 5769-5778] and 0.06 M(-1) s(-1) [Go, M. K., Koudelka, A., Amyes, T. L., and Richard, J. P. (2010) Biochemistry 49, 5377-5389] have been determined for the wild-type- and K12G mutant TIM-catalyzed deuterium exchange reactions of [1-(13)C]GA, respectively, to form [1-(13)C,2,2-di-(2)H]GA. These data show that TIM and BSA exhibit a modest catalytic activity toward deprotonation of the alpha-hydroxy alpha-carbonyl carbon. We suggest that this activity is intrinsic to many globular proteins, and that it must be enhanced to demonstrate meaningful de novo design of protein catalysts of proton transfer at alpha-carbonyl carbon.

Controlled “Grafting-from” of poly[styrene- co-maleic anhydride] onto polydienes using nitroxide chemistry

High-throughput experimentation was used for the functionalization of polybutadiene and polyisoprene with several kinds of nitroxide moieties at 135 °C, as well as for kinetic investigations of the controlled free radical grafting of styrene and maleic anhydride onto the functionalized polydienes at 125 °C. The functionalized polymers were analyzed by GPC, 1H NMR and FT-IR and the control of the grafting process was assessed by kinetic measurements and GPC analysis. The best control in the molecular weight of the grafts was observed for the polydienes functionalized with 4-oxo-TEMPO. TEMPO functionalization did not render sufficient nitroxide moieties to achieve controlled grafting, while polydienes functionalized with other 4-hydroxy TEMPO derivatives exhibited some level of grafting control at early reaction times, which was lost in later stages of the polymerization reaction. SG1 apparently decomposed at the tested reaction temperatures, as polydienes functionalized with SG1 did not show any level of control during the grafting process.

Effects of Multiple Promotion of the Direct Synthesis Contact Mass with P, Zn, and Sn on the Synthesis of Methylchlorosilanes

The Direct Synthesis, or Rochow Synthesis, involves the reaction of methyl chloride, CH3Cl (MeCl), with Cu–Si contact masses (promoted with 1–2% of Zn, Sn, and P) to form methylchlorosilanes. Flow reactor studies (1 bar MeCl at 300 °C) showed that contact masses promoted with Zn, Sn, and P (triply promoted) demonstrated the highest Si and MeCl conversion at early reaction times. In situ infrared spectroscopy suggested that in contrast to the doubly promoted catalysts (where CH3 groups were primarily bound to Si), surface CH3 showed appreciable binding to the copper component of the triply promoted contact mass. This change in surface composition ultimately led to a drop in reactivity and selectivity of the triply promoted catalyst.

Effect of compatibility between solvent and poly(vinyl chloride) on dechlorination of poly(vinyl chloride)

In this study, the use of diethylene glycol (DEG), triethylene glycol (TEG), n-C10H21OH, and ethylene glycol (EG) as solvents for NaOH in the dechlorination of poly(vinyl chloride) (PVC) was investigated. In the early reaction time, the degrees of dechlorination for DEG, TEG, and n-C10H21OH were notably higher than that for EG. Further, the high compatibility between PVC and the solvents was considered to result in the easy penetration of the solvent and OH− into PVC particles, leading to the acceleration of dechlorination in the early reaction stage. An improvement of the dechlorination was actually observed for DEG and TEG compared with EG. The solvent with the best compatibility to PVC, n-C10H21OH, however, showed little improvement due to the formation of a protective polyene layer on the surface of the PVC particles.