scholarly journals Flow Giese reaction using cyanoborohydride as a radical mediator

2013 ◽  
Vol 9 ◽  
pp. 1791-1796 ◽  
Author(s):  
Takahide Fukuyama ◽  
Takuji Kawamoto ◽  
Mikako Kobayashi ◽  
Ilhyong Ryu
Keyword(s):  
Residence Time ◽  
Continuous Flow ◽  
Flow System ◽  
Ethyl Acrylate ◽  
Sodium Cyanoborohydride ◽  
Reaction Conditions ◽  
Radical Trap ◽  
Flow Microreactor ◽  
Alkyl Iodides ◽  
Tertiary Alkyl

Tin-free Giese reactions, employing primary, secondary, and tertiary alkyl iodides as radical precursors, ethyl acrylate as a radical trap, and sodium cyanoborohydride as a radical mediator, were examined in a continuous flow system. With the use of an automated flow microreactor, flow reaction conditions for the Giese reaction were quickly optimized, and it was found that a reaction temperature of 70 °C in combination with a residence time of 10–15 minutes gave good yields of the desired addition products.

Transformation of 1-Butene over Synthetic Zeolites

1992 ◽  
Vol 57 (4) ◽  
pp. 869-881 ◽  
Author(s):  
Italo Ferino ◽  
Roberto Monaci ◽  
Vincenzo Solinas ◽  
Lucio Forni ◽  
Antonio Rivoldini ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Continuous Flow ◽  
Liquid Mixture ◽  
Isomerization Reaction ◽  
Reaction Conditions ◽  
Title Reaction ◽  
Y Zeolites ◽  
Temperature Range ◽  
Flow Microreactor ◽  
Synthetic Zeolites

The behaviour of several zeolites as catalysts for the title reaction has been investigated by means of a continuous flow microreactor. Runs performed at atmospheric pressure indicated that at 423 K the completely protonic forms of the zeolites catalyze just the isomerization reaction. In the case of Y zeolites, oligomerization occurs only over the partially decationated samples, in the temperature range between 373 and 423 K and W/F between 0.2 and 22 gcath/g1-but, to an extent which depends on the reaction conditions. Most of the catalysts were tested also under pressure (4.05 MPa) at 423 K. The protonic forms of Y and ZSM-5 zeolites seem promising catalysts in terms of both conversion and selectivity to oligomers. The 1-olefins account for 30% of the entire olefinic mixture. The octenes, which account for 70% of the liquid mixture, are mostly formed of dimethylhexenes. Trimers are also formed during the reaction and, in the very particular case of H[B]ZSM-5, tetramers are produced.

scholarly journals 5-Hydroxymethylfurfural Hydrodeoxygenation to 2,5-Dimethylfuran in Continuous-Flow System over Ni on Nitrogen-Doped Carbon

2020 ◽  
Vol 1 (2) ◽  
pp. 106-115 ◽  
Author(s):  
Francesco Brandi ◽  
Marius Bäumel ◽  
Irina Shekova ◽  
Valerio Molinari ◽  
Majd Al-Naji
Keyword(s):  
Continuous Flow ◽  
Noble Metals ◽  
Flow System ◽  
High Catalytic Activity ◽  
Reaction Conditions ◽  
Transportation Fuels ◽  
Nitrogen Doped ◽  
Continuous Flow System ◽  
Alternative Feedstock ◽  
Nitrogen Doped Carbon

Waste lignocellulosic biomass is sustainable and an alternative feedstock to fossil resources. Among the lignocellulosic derived compounds, 2,5-dimethylfuran (DMF) is a promising building block for chemicals, e.g., p-xylene, and a valuable biofuel. DMF can be obtained from 5-hydroxymethylfurfural (HMF) via catalytic deoxygenation using non-noble metals such as Ni in the presence of H2. Herein, we present the synthesis of DMF from HMF using 35 wt.% Ni on nitrogen-doped carbon pellets (35Ni/NDC) as a catalyst in a continuous flow system. The conversion of HMF to DMF was studied at different hydrogen pressures, reaction temperatures, and space times. At the best reaction conditions, i.e., 423 K, 8.0 MPa, and space time 6.4 kgNi h kgHMF−1, the 35Ni/NDC catalyst exhibited high catalytic activity with HMF conversion of 99 mol% and 80 mol% of DMF. These findings can potentially contribute to the transition toward the production of sustainable fine chemicals and liquid transportation fuels.

Rapid and Efficient Coupling Reaction of Azo Dyes in a Continuous-Flow Microreactor

2012 ◽  
Vol 560-561 ◽  
pp. 516-520
Author(s):  
Wu Bin Yu ◽  
Ming Ming Zheng ◽  
Jian Rong Gao
Keyword(s):  
Reaction Time ◽  
Azo Dyes ◽  
Continuous Flow ◽  
Room Temperature ◽  
High Efficiency ◽  
Coupling Reaction ◽  
Reaction Conditions ◽  
Short Reaction Time ◽  
Flow Microreactor ◽  
Efficient Coupling

A convenient, rapid efficient method for the synthesis of azo dyes has been developed by coupling in a continuous-flow microreactor at room temperature. The advantage of this protocol is its continuousness, high efficiency and selectivity, short reaction time, and milder reaction conditions.

Direct oxidative amination of aromatic aldehydes with amines in a continuous flow system using a metal-free catalyst

RSC Advances ◽  
2016 ◽  
Vol 6 (76) ◽  
pp. 72121-72126 ◽  
Author(s):  
Jiajia Gu ◽  
Zheng Fang ◽  
Chengkou Liu ◽  
Xin Li ◽  
Ping Wei ◽  
...  
Keyword(s):  
Continuous Flow ◽  
Flow System ◽  
Aromatic Aldehydes ◽  
Reaction Conditions ◽  
Oxidative Amination ◽  
Metal Free ◽  
Continuous Flow System

Metal-free oxidative amination of aromatic aldehydes with amines in a continuous flow system under mild reaction conditions.

scholarly journals Photocatalytic trifluoromethoxylation of arenes and heteroarenes in continuous-flow

2020 ◽  
Vol 16 ◽  
pp. 1305-1312
Author(s):  
Alexander V Nyuchev ◽  
Ting Wan ◽  
Borja Cendón ◽  
Carlo Sambiagio ◽  
Job J C Struijs ◽  
...  
Keyword(s):  
Residence Time ◽  
Continuous Flow ◽  
Reaction Yield ◽  
Flow Conditions ◽  
Flow Microreactor ◽  
Microreactor Technology

The first example of photocatalytic trifluoromethoxylation of arenes and heteroarenes under continuous-flow conditions is described. Application of continuous-flow microreactor technology allowed to reduce the residence time up to 16 times in comparison to the batch procedure, while achieving similar or higher yields. In addition, the use of inorganic bases was demonstrated to increase the reaction yield under batch conditions.

Nitrification and Autotrophic Denitrification in Calcium Alginate Beads

1987 ◽  
Vol 19 (1-2) ◽  
pp. 175-182 ◽  
Author(s):  
Z. Lewandowski ◽  
R. Bakke ◽  
W. G. Characklis
Keyword(s):  
Calcium Carbonate ◽  
Calcium Ions ◽  
Continuous Flow ◽  
Calcium Alginate ◽  
Microbial Respiration ◽  
Flow System ◽  
Alginate Beads ◽  
Alginate Gel ◽  
Gel Beads ◽  
Calcium Alginate Gel

Immobilization of nitrifiers and autotrophic denitrifiers (Thiobacillus denitrificans) within calcium alginate gel was demonstrated. Calcium carbonate reagent was immobilized along with bacteria as the stabilizing agent. Protons released as a result of microbial respiration reacted with calcium carbonate producing calcium ions which internally stabilized the calcium alginate gel. The microbially active gel beads were mechanically stable and active for three months in a continuous flow system without addition of calcium.

Effect of electroporation in a continuous flow system on bioaccumulation of magnesium, zinc and calcium ions in Lactobacillus rhamnosus B 442 cells

2021 ◽  
Vol 140 ◽  
pp. 107769
Author(s):  
Sujka Monika ◽  
Pankiewicz Urszula ◽  
Flisar Karel ◽  
Miklavčič Damijan ◽  
Haberl-Meglič Sasa
Keyword(s):  
Calcium Ions ◽  
Continuous Flow ◽  
Flow System ◽  
Lactobacillus Rhamnosus ◽  
Continuous Flow System

Process intensification for enzyme assisted turmeric starch hydrolysis in hydrotropic and supercritical conditions

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yogita P. Labrath ◽  
Prafulla V. Belge ◽  
Uma G. Kulkarni ◽  
Vilas G. Gaikar
Keyword(s):  
Residence Time ◽  
Filtration Rate ◽  
Room Temperature ◽  
Curcuma Longa ◽  
Process Intensification ◽  
Enzyme Treatment ◽  
Starch Hydrolysis ◽  
Reaction Conditions ◽  
Natural Form ◽  
Hydrolysis Of

Abstract The turmeric rhizome (Curcuma longa) contains curcuminoids embedded in the starch matrix. It is thus important to target starch hydrolysis to enhance extraction of curcuminoids. In the case of starch hydrolysis, α-amylase is more efficient when the starch is in a gelatinised form than when it is in its natural form. The present work includes hydrolysis of turmeric starch in its natural and gelatinised forms using α-amylase in hydrotrope solution (HS) and scCO2. The optimum rate of starch hydrolysis was obtained using 200 IU cm−3 of α-amylase, at reaction conditions of 6.5 pH at 328 K when 10% w/w of turmeric powder was stirred at 900 rpm in HSs. The hydrolysis in 15 MPa scCO2 at room temperature required a phase modifier and 40 min of residence time (RT). The enzyme treatment of turmeric powder in HSs increased the filtration rate for curcuminoid extraction (gelatinised and native) compared to untreated turmeric powder.

Developments of a continuous-flow system with immobilized biocatalysts towards sustainable bioprocessing

2021 ◽  
Author(s):  
Apisit Naramittanakul ◽  
Supacha Buttranon ◽  
A. Petchsuk ◽  
Pimchai Chaiyen ◽  
Nopphon Weeranoppanant
Keyword(s):  
Continuous Flow ◽  
Flow System ◽  
Continuous Flow System ◽  
P Immobilization ◽  
Feasible Solutions

Immobilization methods have emerged as feasible solutions for increasing the re-usability of biocatalysts, and for simplifying their separation from the desired products. Immobilized biocatalysts can directly be applied to a...

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