Cyclic reaction-induced enhancement in the dehydrogenation performances of the KNH2-doped LiNH2 and LiH system

2020 ◽  
Vol 45 (48) ◽  
pp. 25927-25934 ◽  
Author(s):  
Chao Ping ◽  
Bao-Qi Feng ◽  
Jun Ge ◽  
Guang-Zhen Li ◽  
Wei Zhu ◽  
...  
Keyword(s):  
2012 ◽  
Vol 12 (1) ◽  
pp. 15
Author(s):  
Amran Laga

Degradation of starch by the glucosyltransferase enzyme (CGTase) to produce the primary product of chainsplitting undergoes an intramolecular reaction without the participation of water molecule. From this process, α-1,4-Linked cyclic product, known as cyclodextrins, are formed. The aim of the research was to cut amylopectinbranch in order to produce one straight chain, to optimize cyclic reaction formation cyclodextrin by CGTase. Theresearch was devided into 3 stages; (1) debranching enzyme concentration estimation (5,10,15,20, and 25 unit/gram) and the length of otimum reaction to produce straight chain for 5 hours which sample was taken each hour,(2) reaction length time estimation to form cyclodextrin in order to use debranching products (straight chain) assubstrates, the reaction length for 360 minutes and sample taken each for 30 minutes, and (3) the best substrateconcentration for straight chain (20-40% w/v) to produce cyclodextrin. The result showed that enzyme concentrationtreatment and optimal length reaction will produce straight chain with enzyme concentration of 14 units/gram for3 hours and straight chain product of 20 units/gram for 1 hour with straight chain product of 83.5%. The optimumlength of reaction for cyclodextrin formation from amylose produced from the de-branching process was 240minutes. The amount of cyclodextrin produced was 143.45 g/L with conversion value of 47.81% at 30% (w/v)substrate concentration. Highest yield of cyclodextrin (154,28 g/L) and conversion value of 44.08% was obtained at35% (w/v) substrate concentration


2021 ◽  
Vol 43 (3) ◽  
pp. 308-308
Author(s):  
Guosheng Wang Guosheng Wang ◽  
Siyu Han and Ronghui Xu Siyu Han and Ronghui Xu

Berberine hydrochloride is a natural alkaloid with significant antitumor activities against many types of cancer cells, can be synthesized by cyclic reaction with hydrochloride condensate and glyoxal as raw materials and copper chloride as catalyst. In this study, the transition and energy change for the each reaction step was calculated by the density functional theory program Dmol3 in Materials Studio 2017. and the results testified that there are two ring formation in the cycliztion process, and according to the result we proposed the mechanism of this cyclization reaction. We also use infrared and ultraviolet spectroscopy to monitor the reaction process in real time and prove the ring formation process. The reaction mechanism was firstly proposed at the basic results of above.


2019 ◽  
Vol 93 (1-2) ◽  
pp. 131-157 ◽  
Author(s):  
Xuteng Xi ◽  
Charlie Kong ◽  
Jianqiang Zhang

1993 ◽  
Vol 76 (9) ◽  
pp. 2389-2392 ◽  
Author(s):  
Hidehiko Kobayashi ◽  
Kenichi Shimosaka ◽  
Miki Saitoh ◽  
Takashi Mitamura

1967 ◽  
Vol 20 (7) ◽  
pp. 1335 ◽  
Author(s):  
AH Ewald ◽  
DJ Ottley

Rates of the cyclization of 4-chlorobutanol and of some analogous non- cyclic solvolysis reactions have been measured in water, methanol, and aqueous acetone at pressures up to 3000 atm. The volume of activation of the cyclic reaction is less negative than those of the linear reactions, in each solvent, but it is suggested that the transition states of both types of reaction may be solvated to about the same extent. The volume of activation for the formation of an eight-membered ring in the cyclization of 4-bromobutylcatechol monoether was also determined.


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