Speed organic reaction rate...increase yields...lower costs with a B&A® BORON TRIFLUORIDE CATALYST

1966 ◽  
Vol 44 (10) ◽  
pp. obc
2012 ◽  
Vol 16 (3) ◽  
pp. 152
Author(s):  
Wiji Mangestiyono ◽  
A.P. Bayuseno ◽  
Stefanus Muryanto

Wiji Mangestiyono, , A.P. Bayuseno, Stefanus Muryanto, in this paper explain that the problem of gypsum scaling becomes a trouble for some industry in which use some water for its system. Some disadvanteges come up because of : the time of industrial process will be more longer and production cost increase necesery.To prevent the growth of scale, the experiment must be done. Researcher try to answer this problem so an experimental about kinetic study of gypsum scaling established. Flowrate would be a parameter with assume that it has effect on reaction flow. The result of  this experiment are : reaction rate increase when flow rate increase; adition some aditives becomes reaction rate decrease. Keywords : crystal, flow rate, reactio rate, gipsum


2011 ◽  
Vol 421 ◽  
pp. 754-758
Author(s):  
Sheng Dai ◽  
Yun Dian Zhang ◽  
Peng Zai

A small-high efficiency ultrasonic reactor tool is designed by this paper. This tool can promote chemical reaction rate, increase the reaction yield. Having analyzed its modal frequency with ANSYS software and assembled the manufactured tool with transducer and horn, we can use Impedance analyzer to test the actual frequency. Since there are only minor errors between actual resonant frequency and the modal frequency, this method meets the design requirements.


Catalysts ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 642 ◽  
Author(s):  
Dongin Kim ◽  
Geonwoo Kim ◽  
Hyeonbin Bae ◽  
Eunwoo Kim ◽  
Byunghyun Moon ◽  
...  

In this study, the synthesis of a novel catalyst WO3/MoCl5 was carried out by the thermal method. The method gave an entirely different product compared to previous studies that doped Mo on the surface of semiconductor metal oxides. The degradation reaction of crystal violet (CV) and rhodamine B (RB) dye were done without any energy source. The results showed an incomparably superior result for degradation, with a reaction rate constant of 1.74 s−1 for 30 ppm CV, 1.08 s−1 for 30 ppm RB, and a higher value than 1 s−1 for both cases of 50 ppm dye solution. To the author’s knowledge, this catalyst has the highest reaction rate compared to other studies that targeted CV and RB, with an immense reaction rate increase of more than 100 times. Reusability of the three trials was verified, and the only process required was washing the catalyst after the reaction. One of the drawbacks of the advanced oxidation process (AOP), which has a degradation percent limit, has been solved, since 100% mineralization of the dye was available using this catalyst. FT-IR spectroscopy revealed that W-O-Mo linkage was successfully processed while Mo-Cl linkage has retained. 1H-NMR spectroscopy results confirmed that the degradation product of the dye treated by simple MoCl5 and WO3/MoCl5 was different. Deep inspection of specific regions of NMR fields gave necessary information about the degradation product using WO3/MoCl5.


1989 ◽  
Vol 262 (1) ◽  
pp. 253-260
Author(s):  
J P Tahon ◽  
C Gielens ◽  
C Vinckier ◽  
R Witters ◽  
M De Ley ◽  
...  

The rate of the reaction of Astacus leptodactylus methaemocyanin with NO follows the Henderson-Hasselbalch equation with a pKa of 5.85, suggesting that one imidazole ligand of Cu was exchanged for NO. The reaction is blocked by F- as a bridging ligand. The same imidazole residue might be responsible for the decomposition of nitrosylhaemocyanin, [Cu1NO+CuII], with an unlocated binding site for NO, into methaemocyanin and NO, as the rate increase with pH. NO could react preferentially with CuA of Helix pomatia methaemocyanin, CuA′IICuBII, as it possibly has only two histidine ligands instead of the three of CuA in Astacus haemocyanin. This difference might explain the higher formation rate and the much greater stability of Helix nitrosylhaemocyanin. The fast reaction is governed by a pKa of 6.80, probably of a bridging mu-aquo ligand. With F- or a mu-hydroxo bridging ligand a low reaction rate was still observed, in contrast with Astacus methaemocyanin. Helix nitrosylhaemocyanin was transformed by N3- into methaemocyanin with the liberation of N2 and N2O. This methaemocyanin could almost quantitatively be regenerated with H2O2. Helix nitrosylhaemocyanin was only partially regenerated by a direct treatment with H2O2 and almost quantitatively by HONH2 in a similar fairly fast reaction, followed by a much slower one.


2007 ◽  
Vol 80 (5) ◽  
pp. 739-750 ◽  
Author(s):  
B. Vega ◽  
N. Agulló ◽  
S. Borrós

Abstract The natural rubber vulcanization mechanism has been studied using microwaves as a heating source. The influence of such heating system on the mechanism reaction has been elucidated. In order to simplify the study of this process, squalene has been used as a Model Compound Vulcanization (MCV) for natural rubber and N-cyclohexyl-2-benzothiazolesulfenamide (CBS) as an accelerator. The accelerator fading, the crosslinking degree, the reversion process and the effect of the double bond have been studied and the results have been compared with previous results of our group using MCV with conventional heating. As well as the expected reaction rate increase, a noticeable change in the crosslink degree has been observed. Furthermore, some differences have been detected in the amount of the intermediate compounds formed during the reaction and in the sulfur transfer to the squalene chain. Strong differences have been also observed regarding the role of the activator in the vulcanization when microwaves are used.


1987 ◽  
Vol 111 ◽  
Author(s):  
Peter Sjövall ◽  
Bo Hellsing ◽  
Karl-Erik Keck ◽  
Bengt Kasemo

AbstractThe influence of K, deposited on a carbon surface, on the oxidation of carbon in O2 was investigated. Reaction rate measurements, carried through in a UHV-system by use of AES, showed that potassium increases the reaction rate by up to ∼ 104 times. A theoretical model, based on the assumption that O2 dissociation is the rate limiting step, has been developed. The model shows that a charge transfer mechanism can explain the observed rate increase. Results from TPD/TPR-measurements indicate that the sticking probablility for O2 on a graphite surface with predeposited K is approximately independent on K coverage for coverages down to 0.5 × 1014 cm−2, corresponding to an effective radius of K of ∼ 7.3 Å.


Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 48 ◽  
Author(s):  
Yasmine M. Hajar ◽  
Balaji Venkatesh ◽  
Elena A. Baranova

Electrochemical promotion of catalysis (EPOC) was investigated for methane complete oxidation over palladium nano-structured catalysts deposited on yttria-stabilized zirconia (YSZ) solid electrolyte. The catalytic rate was evaluated at different temperatures (400, 425 and 450 °C), reactant ratios and polarization values. The electrophobic behavior of the catalyst, i.e., reaction rate increase upon anodic polarization was observed for all temperatures and gas compositions with an apparent Faradaic efficiency as high as 3000 (a current application as low as 1 μA) and maximum rate enhancement ratio up to 2.7. Temperature increase resulted in higher enhancement ratios under closed-circuit conditions. Electrochemical promotion experiments showed persistent behavior, where the catalyst remained in the promoted state upon current or potential interruption for a long period of time. An increase in the polarization time resulted in a longer-lasting persistent promotion (p-EPOC) and required more time for the reaction rate to reach its initial open-circuit value. This was attributed to continuous promotion by the stored oxygen in palladium oxide, which was formed during the anodic polarization in agreement with p-EPOC mechanism reported earlier.


Author(s):  
Kathleen B. Reuter

The reaction rate and efficiency of piperazine to 1,4-diazabicyclo-octane (DABCO) depends on the Si/Al ratio of the MFI topology catalysts. The Al was shown to be the active site, however, in the Si/Al range of 30-200 the reaction rate increases as the Si/Al ratio increases. The objective of this work was to determine the location and concentration of Al to explain this inverse relationship of Al content with reaction rate.Two silicalite catalysts in the form of 1/16 inch SiO2/Al2O3 bonded extrudates were examined: catalyst A with a Si/Al of 83; and catalyst B, the acid/phosphate Al extracted form of catalyst A, with a Si/Al of 175. Five extrudates from each catalyst were fractured in the transverse direction and particles were obtained from the fracture surfaces near the center of the extrudate diameter. Particles were also obtained from the outside surfaces of five extrudates.


Author(s):  
C. S. Lin ◽  
W. A. Chiou ◽  
M. Meshii

The galvannealed steel sheets have received ever increased attention because of their excellent post-painting corrosion resistance and good weldability. However, its powdering and flaking tendency during press forming processes strongly impairs its performance. In order to optimize the properties of galvanneal coatings, it is critical to control the reaction rate between solid iron and molten zinc.In commercial galvannealing line, aluminum is added to zinc bath to retard the diffusion rate between iron and zinc by the formation of a thin layer of Al intermetallic compound on the surface of steel at initial hot-dip galvanizing. However, the form of this compound and its transformation are still speculated. In this paper, we report the direct observations of this compound and its transformation.The specimens were prepared in a hot-dip simulator in which the steel was galvanized in the zinc bath containing 0.14 wt% of Al at a temperature of 480 °C for 5 seconds and was quenched by liquid nitrogen.


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