Facile transformation of the five-membered exocyclic E-ring in 132-demethoxycarbonyl chlorophyll derivatives by molecular oxygen with titanium oxide in the dark

2015 ◽  
Vol 19 (04) ◽  
pp. 631-637 ◽  
Author(s):  
Naoya Takahashi ◽  
Keiya Hirota ◽  
Yoshitaka Saga
Keyword(s):  
Molecular Oxygen ◽  
Present Method ◽  
Ester Group ◽  
Paper Report ◽  
No Removal ◽  
Mild Conditions ◽  
One Step ◽  
Facile Transformation ◽  
Hydrolysis Of ◽  
Chlorophyll Derivatives

Major photosynthetic pigments chlorophyll(Chl)s have a cyclic tetrapyrrole with a five-membered exocyclic E-ring as photofunctional moieties. Its transformation is one promising methodology to develop functional pigments based on Chl chemistry. This paper report a facile conversion from Chl derivatives lacking the 132-methoxycarbonyl moiety to the corresponding chlorophyllous pigments, whose exocyclic E-ring had two oxo groups at the 131- and 132-positions, by contact with the TiO 2 particles in the presence of molecular oxygen in the dark. The conversion proceeded under mild conditions without hydrolysis of the ester group in the 17-propionate residue. This is in sharp contrast to the inevitable ester cleavage in the conventional synthesis of Chl derivatives that possess α-diketone in the E-ring. The reaction properties in the present method allowed us to perform a one-step conversion of Chl derivatives esterified with a natural isoprenoid alcohol phytol to the corresponding 132-oxo-pigments. No removal of central Zn from the chlorin macrocycle occurred in the present conversions using Zn pyropheophytin a as a starting material.

Effect of removing hemicellulose and lignin synchronously under mild conditions on enzymatic hydrolysis of corn stover

2020 ◽  
Vol 204 ◽  
pp. 106407 ◽  
Author(s):  
Shengxin An ◽  
Wenzhi Li ◽  
Fengyang Xue ◽  
Xu Li ◽  
Ying Xia ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Corn Stover ◽  
Mild Conditions ◽  
Hydrolysis Of

One-step fabrication of Pd-embedded hierarchically porous carbon micro-spheres for formaldehyde removal under mild conditions

2021 ◽  
Author(s):  
Zhigang Ren ◽  
peng zhao ◽  
Ye Zhang ◽  
Yang Yu ◽  
xiaoxuan lv ◽  
...  
Keyword(s):  
Porous Carbon ◽  
Carbon Microspheres ◽  
Carbon Spheres ◽  
Pickering Emulsions ◽  
Hierarchically Porous ◽  
Mild Conditions ◽  
Formaldehyde Removal ◽  
One Step

Micron-sized carbon spheres synthesized via pickering emulsions has attracted much attention in recent two years. In present paper, we prepared palladium (Pd) and nitrogen co-embedded carbon microspheres for formaldehyde (HCHO)...

scholarly journals Adjustment of Hydrophobic Properties of Cellulose Materials

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1241
Author(s):  
Michael Ioelovich
Keyword(s):  
Ester Group ◽  
Hydroxyl Groups ◽  
Chemical Methods ◽  
Hydrophobic Properties ◽  
Cellulose Esters ◽  
Cellulose Modification ◽  
Polar Groups ◽  
Polar Substituents ◽  
Hydrolysis Of ◽  
Cellulose Materials

In this study, physicochemical and chemical methods of cellulose modification were used to increase the hydrophobicity of this natural semicrystalline biopolymer. It has been shown that acid hydrolysis of the initial cellulose increases its crystallinity, which improves hydrophobicity, but only to a small extent. A more significant hydrophobization effect was observed after chemical modification by esterification, when polar hydroxyl groups of cellulose were replaced by non-polar substituents. The esterification process was accompanied by the disruption of the crystalline structure of cellulose and its transformation into the mesomorphous structure of cellulose esters. It was found that the replacement of cellulose hydroxyls with ester groups leads to a significant increase in the hydrophobicity of the resulting polymer. Moreover, the increase of the number of non-polar groups in the ester substituent contributes to rise in hydrophobicity of cellulose derivative. Depending on the type of ester group, the hydrophobicity increased in the following order: acetate < propionate < butyrate. Therefore, tributyrate cellulose (TBC) demonstrated the most hydrophobicity among all studied samples. In addition, the mixed ester, triacetobutyrate cellulose (TAB), also showed a sufficiently high hydrophobicity. The promising performance properties of hydrophobic cellulose esters, TBC and TAB, were also demonstrated.

scholarly journals Synthesis of bifunctional nanocatalyst from waste palm kernel shell and its application for biodiesel production

RSC Advances ◽  
2020 ◽  
Vol 10 (45) ◽  
pp. 27183-27193
Author(s):  
Rose Fadzilah Abdullah ◽  
Umer Rashid ◽  
Yun Hin Taufiq-Yap ◽  
Mohd Lokman Ibrahim ◽  
Chawalit Ngamcharussrivichai ◽  
...  
Keyword(s):  
Palm Kernel ◽  
Biodiesel Production ◽  
Palm Kernel Shell ◽  
Mild Conditions ◽  
One Step

The potential of bifunctional nanocatalysts obtained from waste palm kernel shell (PKS) was investigated for one-step transesterification–esterification under mild conditions.

Selective acid hydrolysis of 2,4,6-trimethylbenzyl esters and its application in peptide synthesis

1966 ◽  
Vol 19 (8) ◽  
pp. 1511 ◽  
Author(s):  
FHC Stewart
Keyword(s):  
Acid Hydrolysis ◽  
Peptide Synthesis ◽  
Trifluoroacetic Acid ◽  
Ester Group ◽  
Protecting Groups ◽  
Alkaline Conditions ◽  
Hydrolysis Of

Experiments with various N-acylamino acid 2,4,6-trimethylbenzyl esters have shown that the ester group is cleaved selectively by cold trifluoroacetic acid without affecting benzyloxycarbonyl, formyl, or phthaloyl amino-protecting groups present. The possible value of this selective behaviour in peptide syntheses where the use of alkaline conditions would be detrimental is illustrated by the synthesis of certain dipeptide derivatives.

One Step Microwave-Assisted Synthesis of Fluorinated Titania Photocatalyst

2015 ◽  
Vol 670 ◽  
pp. 177-182
Author(s):  
Alexey A. Sadovnikov ◽  
Alexander E. Baranchikov ◽  
Vladimir Kozik ◽  
Lyudmila P. Borilo ◽  
Sergey A. Kozyukhin ◽  
...  
Keyword(s):  
Ammonium Fluoride ◽  
Organic Dye ◽  
Microwave Assisted Synthesis ◽  
Dye Sensitized ◽  
Microwave Assisted ◽  
One Step ◽  
Nanocrystalline Titanium ◽  
Nanocrystalline Titanium Dioxide ◽  
Titania Photocatalyst ◽  
Hydrolysis Of

Microwave-assisted high temperature hydrolysis of titanium oxysulfate, in the presence of ammonium fluoride, allows synthesizing nanocrystalline titanium dioxide photocatalysts possessing photocatalytic activity as high as the commercial photocatalyst Evonik Aeroxide® TiO2 P 25. Dye-sensitized reactions play an important role in organic dye discoloration in the presence of fluorinated titania.

Production of novel carbon nanostructures by electrochemical reduction of polychlorinated organic rings under mild conditions for supercapacitors

2021 ◽  
Author(s):  
Züleyha Kudaş ◽  
Emir Çepni ◽  
Emre Gür ◽  
Duygu Ekinci
Keyword(s):  
Carbon Source ◽  
Electrochemical Reduction ◽  
Electrochemical Method ◽  
Carbon Nanostructures ◽  
Electrochemical Growth ◽  
Mild Conditions ◽  
One Step ◽  
The One ◽  
Carbon Based

Here, new carbon-based nanostructures were prepared by the one-step electrochemical method using hexagonal and pentagonal polychlorinated organic rings as carbon source. The electrochemical growth of carbon nanostructures on substrates was...

scholarly journals Optimized acid hydrolysis of the polysaccharides from the seaweed Solieria filiformis (Kützing) P.W. Gabrielson for bioethanol production

2017 ◽  
Vol 39 (4) ◽  
pp. 423 ◽  
Author(s):  
George Meredite Cunha de Castro ◽  
Norma Maria Barros Benevides ◽  
Maulori Curié Cabral ◽  
Rafael De Souza Miranda ◽  
Enéas Gomes Filho ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Sulfuric Acid ◽  
Acid Hydrolysis ◽  
Kinetic Parameters ◽  
Renewable Resource ◽  
Bioethanol Production ◽  
Seaweed Species ◽  
Mild Conditions ◽  
Hydrolysis Of ◽  
Solieria Filiformis

 The seaweeds are bio-resource rich in sulfated and neutral polysaccharides. The tropical seaweed species used in this study (Solieria filiformis), after dried, shows 65.8% (w/w) carbohydrate, 9.6% (w/w) protein, 1.7% (w/w) lipid, 7.0% (w/w) moisture and 15.9% (w/w) ash. The dried seaweed was easily hydrolyzed under mild conditions (0.5 M sulfuric acid, 20 min.), generating fermentable monosaccharides with a maximum hydrolysis efficiency of 63.21%. Galactose and glucose present in the hydrolyzed were simultaneously fermented by Saccharomyces cerevisiae when the yeast was acclimated to galactose and cultivated in broth containing only galactose. The kinetic parameters of the fermentation of the seaweed hydrolyzed were Y(P⁄S) = 0.48 ± 0.02 g.g−1, PP = 0.27 ± 0.04 g.L−1.h−1, h = 94.1%, representing a 41% increase in bioethanol productivity. Therefore, S. filiformis was a promising renewable resource of polysaccharides easily hydrolyzed, generating a broth rich in fermentable monosaccharides for ethanol production. 

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