Organic Acid-Catalyzed Polyurethane Formation via a Dual-Activated Mechanism: Unexpected Preference of N-Activation over O-Activation of Isocyanates

2013 ◽  
Vol 135 (43) ◽  
pp. 16235-16241 ◽  
Author(s):  
Haritz Sardon ◽  
Amanda C. Engler ◽  
Julian M. W. Chan ◽  
Jeannette M. García ◽  
Daniel J. Coady ◽  
...  
Keyword(s):  
Organic Acid ◽  
Acid Catalyzed

scholarly journals A sustainable strategy for production and functionalization of nanocelluloses

2019 ◽  
Vol 91 (5) ◽  
pp. 865-874 ◽  
Author(s):  
Armando Córdova ◽  
Samson Afewerki ◽  
Rana Alimohammadzadeh ◽  
Italo Sanhueza ◽  
Cheuk-Wai Tai ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Metal Ions ◽  
Organic Acid ◽  
Surface Functionalization ◽  
Fluorescent Probes ◽  
Organic Molecules ◽  
Cross Coupling ◽  
Palladium Nanoparticle ◽  
Acid Catalyzed ◽  
Nanoparticle Catalyst

Abstract A sustainable strategy for the neat production and surface functionalization of nanocellulose from wood pulp is disclosed. It is based on the combination of organocatalysis and click chemistry (“organoclick” chemistry) and starts with nanocellulose production by organic acid catalyzed hydrolysis and esterification of the pulp under neat conditions followed by homogenization. This nanocellulose fabrication route is scalable, reduces energy consumption and the organic acid can be efficiently recycled. Next, the surface is catalytically engineered by “organoclick” chemistry, which allows for selective and versatile attachment of different organic molecules (e.g. fluorescent probes, catalyst and pharmaceuticals). It also enables binding of metal ions and nanoparticles. This was exemplified by the fabrication of a heterogeneous nanocellulose-palladium nanoparticle catalyst, which is used for Suzuki cross-coupling transformations in water. The disclosed surface functionalization methodology is broad in scope and applicable to different nanocelluloses and cellulose based materials as well.

Hydrogen Generation From Acetic Acid Catalyzed Magnesium Hydride Using an On-Demand Hydrogen Reactor

2016 ◽  
Author(s):  
Tien-Chien Jen ◽  
Joshua Adeniran ◽  
Esther Akinlabi ◽  
Chung-Hsing Chao ◽  
Yen-Hsi Ho ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Organic Acid ◽  
Hydrogen Generation ◽  
Magnesium Hydride ◽  
Hydrolysis Reaction ◽  
Hydrogen Yield ◽  
Acetic Acid Concentration ◽  
External Temperature ◽  
On Demand ◽  
Acid Catalyzed

This study reports an acetic acid catalyzed hydrolysis reaction for hydrogen generation from magnesium hydride (MgH2) using an on-demand hydrogen reactor. Acetic acid, a weak and benign organic acid, has been reported as a single catalyst in hydrolysis reaction for hydrogen generation using other substrates, but this is the first study where acetic acid has been employed as a catalyst in a magnesium hydride hydrolysis reaction for hydrogen generation. In this study, the effects of MgH2 weight, acetic acid concentration and external temperature on hydrogen generation from MgH2 were examined. The results of the hydrolysis reaction indicated that the weight of MgH2 was the major factor influencing hydrogen generation, followed by the concentration of acetic acid while the effect of external temperature was insignificant. Similarly, hydrogen yield was proportional to the weight of MgH2 with a reported maximum hydrogen yield at each weight been: 0.4g (∼ 0.07 L); 0.8 g (∼ 0.125 L) and 1.2 g (∼1.285 L). The successful use of acetic acid in the study reinforced the versatility of the on-demand hydrogen reactor and as a scalable technology for hydrogen generation.

scholarly journals Organic Acid-Catalyzed Subcritical Water Hydrolysis of Immature Citrus unshiu Pomace

Foods ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 18
Author(s):  
Sang-Bin Lim
Keyword(s):  
Citric Acid ◽  
Organic Acid ◽  
Acid Concentration ◽  
Subcritical Water ◽  
Biological Activities ◽  
Citrus Unshiu ◽  
Citric Acid Concentration ◽  
Acid Catalyzed ◽  
Inhibitory Activities ◽  
Hydrolysis Of

Immature Citrus unshiu pomace (ICUP) was hydrolyzed under organic acid-catalyzed, subcritical water (SW) conditions to produce flavonoid monoglucosides (hesperetin-7-O-glycoside and prunin) and aglycons (hesperetin and naringenin) with high biological activities. The results of single-factor experiments showed that with 8 h of hydrolysis and an increasing citric acid concentration, the yield of flavonoid monoglucosides (hesperetin-7-O-glycoside and prunin) increased from 0 to 7% citric acid. Afterward, the hesperetin-7-O-glycoside yield remained constant (from 7 to 19% citric acid) while the pruning yield decreased with 19% of citric acid, whereas the aglycon yield increased continuously. In response surface methodology analysis, a citric acid concentration and hydrolysis duration of 13.34% and 7.94 h were predicted to produce the highest monoglucoside yield of 15.41 mg/g, while 18.48% citric acid and a 9.65 h hydrolysis duration produced the highest aglycon yield of 10.00 mg/g. The inhibitory activities of the SW hydrolysates against pancreatic lipase (PL) and xanthine oxidase (XO) were greatly affected by citric acid concentration and hydrolysis duration, respectively. PL and α-glucosidase inhibition rates of 88.2% and 62.7%, respectively, were achieved with 18.48% citric acid and an 8 h hydrolysis duration, compared to 72.8% for XO with 16% citric acid and 12 h of hydrolysis. This study confirms the potential of citric acid-catalyzed SW hydrolysis of ICUP for producing flavonoid monoglucosides and aglycons with enhanced enzyme inhibitory activities.

Kinetics and Mechanism of Acid-Catalyzed Decomposition of 1,3-Bis(4-methylphenyl)triazene in Hexane-Organic Acid Medium

1996 ◽  
Vol 61 (3) ◽  
pp. 355-363 ◽  
Author(s):  
Miroslav Ludwig ◽  
Miriam Kabíčková
Keyword(s):  
Kinetic Model ◽  
Organic Acid ◽  
Acid Medium ◽  
Rate Constant ◽  
Fourth Order ◽  
Kinetics And Mechanism ◽  
Acid Catalyzed ◽  
Kinetics Of

The kinetics of acid-catalyzed decomposition of 1,3-bis(4-methylphenyl)triazene have been studied in mixtures of hexane and organic acid of various ratios using acetic, isovaleric, and pivalic acids as the catalysts. In all the cases, a monotonously increasing dependence of the observed rate constant upon mol fraction of the acid has been found. The results obtained are discussed with the help of the classic third- and fourth-order functions by Margules and the respective kinetic model. The main catalyzing particle appears to be the dimer of the respective acid, the reaction probably going via a complex formed by two molecules of acid and one molecule of the triazene.

Salt-assisted organic-acid-catalyzed depolymerization of cellulose

2010 ◽  
Vol 12 (10) ◽  
pp. 1844 ◽  
Author(s):  
Thorsten vom Stein ◽  
Philipp Grande ◽  
Fabrizio Sibilla ◽  
Ulrich Commandeur ◽  
Rainer Fischer ◽  
...  
Keyword(s):  
Organic Acid ◽  
Acid Catalyzed

Polycondensation of lactic acid catalyzed by organic acid anhydrides

2007 ◽  
Vol 56 (10) ◽  
pp. 1261-1264 ◽  
Author(s):  
Yanbin Bai ◽  
Ziqing Lei
Keyword(s):  
Lactic Acid ◽  
Organic Acid ◽  
Acid Catalyzed ◽  
Acid Anhydrides
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