scholarly journals The effect of stirring speed and reactant residence time in the bench scales CSTR on the reaction conversion of ZBS

2021 ◽  
Author(s):  
Herry Poernomo ◽  
Noor Anis Kundari ◽  
Nafiah
Keyword(s):  
Residence Time ◽  
Reaction Conversion

scholarly journals Two-step continuous-flow synthesis of α-terpineol

2020 ◽  
Author(s):  
Beatriz L C de Carvalho ◽  
Anderson R Aguillon ◽  
Raquel A C Leão ◽  
Rodrigo Octavio M A de Souza
Keyword(s):  
Residence Time ◽  
Continuous Flow ◽  
Chloroacetic Acid ◽  
Molar Ratio ◽  
Hydration Reaction ◽  
Continuous Flow Condition ◽  
Reaction Conversion ◽  
Aromatic Substance ◽  
Basic Hydrolysis ◽  
Hydrolysis Of

α-Terpineol is a monoterpene naturally present in essential oils, of high value on the market as it is a compound widely used as a flavoring, aromatic substance in the cosmetics and food industry. This study aims to produce α-terpineol by two different synthetic strategies, using both batch and continuous flow systems, focusing on the optimization of the process, improving the reaction conversion and selectivity. The first strategy adopted was a one-stage hydration reaction of α-pinene by an aqueous solution of chloroacetic acid (molar ratio 1:1 between pinene and the acid) in continuous flow conditions. This reaction was carried out at 80 ºC with a residence time of 15 min, obtaining good values of conversion (72 %) and selectivity (76 %), and productivity of 0.67 Kg.day-1. The second strategy accomplished was a two-step cascade reaction with limonene as starting material, where the first step is a chemo specific double bond addition using trifluoroacetic acid, and the second step is the basic hydrolysis of the ester promoted by a solution of sodium hydroxide (2.25 M) in methanol (1:1). This reaction was adapted to a continuous flow condition, where all steps happen in a residence time of 40 min, at 25 ºC, with no quenching between steps required, giving a conversion of 97 % and selectivity of 81 %, with productivity of 0.12 Kg.day-1.

scholarly journals Simple and rapid hydrogenation of p-nitrophenol with aqueous formic acid in catalytic flow reactors

2013 ◽  
Vol 9 ◽  
pp. 1156-1163 ◽  
Author(s):  
Rahat Javaid ◽  
Shin-ichiro Kawasaki ◽  
Akira Suzuki ◽  
Toshishige M Suzuki
Keyword(s):  
Formic Acid ◽  
Residence Time ◽  
Electroless Plating ◽  
Hydrogen Transfer ◽  
Acid Leaching ◽  
Catalyst Layer ◽  
Side Reaction ◽  
Catalytic Reactors ◽  
Flow Reactors ◽  
Reaction Conversion

The inner surface of a metallic tube (i.d. 0.5 mm) was coated with a palladium (Pd)-based thin metallic layer by flow electroless plating. Simultaneous plating of Pd and silver (Ag) from their electroless-plating solution produced a mixed distributed bimetallic layer. Preferential acid leaching of Ag from the Pd–Ag layer produced a porous Pd surface. Hydrogenation of p-nitrophenol was examined in the presence of formic acid simply by passing the reaction solution through the catalytic tubular reactors. p-Aminophenol was the sole product of hydrogenation. No side reaction occurred. Reaction conversion with respect to p-nitrophenol was dependent on the catalyst layer type, the temperature, pH, amount of formic acid, and the residence time. A porous and oxidized Pd (PdO) surface gave the best reaction conversion among the catalytic reactors examined. p-Nitrophenol was converted quantitatively to p-aminophenol within 15 s of residence time in the porous PdO reactor at 40 °C. Evolution of carbon dioxide (CO2) was observed during the reaction, although hydrogen (H2) was not found in the gas phase. Dehydrogenation of formic acid did not occur to any practical degree in the absence of p-nitrophenol. Consequently, the nitro group was reduced via hydrogen transfer from formic acid to p-nitrophenol and not by hydrogen generated by dehydrogenation of formic acid.

Residence Time in Hyporheic Bioactive Layers Explains Nitrate Uptake in Streams

2020 ◽  
Author(s):  
Angang Li ◽  
Susana Bernal ◽  
Brady Kohler ◽  
Steven A. Thomas ◽  
Eugènia Martí ◽  
...  
Keyword(s):  
Residence Time ◽  
Nitrate Uptake

Modeling the Effect of Flow Structures on Canal System Residence Time

2008 ◽  
Author(s):  
N. P. Benfer ◽  
B. A. King ◽  
C. J. Lemckert ◽  
S. Zigic
Keyword(s):  
Residence Time ◽  
Flow Structures ◽  
Canal System

PEMBUATAN SURFAKTAN DARI ASAM OLEAT

2019 ◽  
Vol 1 (3) ◽  
pp. 68
Author(s):  
Puguh Setyopratomo ◽  
Edy Purwanto ◽  
H. Yefrico ◽  
H. Yefrico
Keyword(s):  
Oleic Acid ◽  
Optimum Condition ◽  
Reaction Temperature ◽  
Catalyst Concentration ◽  
Acid Number ◽  
Esterification Reaction ◽  
Number Density ◽  
Sample Analysis ◽  
Reaction Conversion ◽  
Glycerol Mono

The synthesis of glycerol mono oleic from oleic acid and glycerol is classified as an esterification reaction. This research is aimed to study the influent of reaction temperature and catalyst concentration on reaction conversion. During the experiment the temperature of reaction mixture was varied as 110 oC, 130 oC, and 150 oC, while the catalyst concentration of 1%, 3 %, and 5% was used. The batch experiment was conducted in a glass reactor equipped with termometer, agitator, and reflux condensor. The oleic acid – glycerol mol ratio of 1 : 2 was used as a mixture feed. To maintain the reaction temperature at certain level, the oil bath was used. After the temperature of reaction mixture was reached the expected value, then H2SO4 catalyst was added to the reactor.  To measure the extent of the reaction, every 30 minutes the sample was drawn out from the reactor vessel. The sample analysis include acid number, density, and viscosity measurement. From this research the optimum condition which is the temperature of reaction of 150 oC and 1% catalyst concentration was obtained. At this optimum condition the convertion reach 86% and the analysis of other physical properties of the product show the acid number of 24.12, the density of 0.922 g/cc, and the viscosity of 118.4 cp.

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