Results 241 to 250 of about 38,855 (280)

Chemical change involved in the oxidative-reductive depolymerization of heparin

Carbohydrate Research, 1992
A solution of hog intestinal heparin (average M(r) 12,000, anti-clotting activity 168 USP units/mg) in 0.2 M phosphate buffer (pH 7.2), was incubated in the presence of Fe2+ for 20 h at 50 degrees under an O2 atmosphere to yield oxidative-reductively depolymerized heparin (ORD heparin, average M(r) 3,000, anti-clotting activity 34 USP units/mg ...
K, Nagasawa, H, Uchiyama, N, Sato, A, Hatano   +3 more
openaire   +2 more sources

Formic-acid-induced depolymerization of oxidized lignin to aromatics

Nature, 2014
Lignin is a heterogeneous aromatic biopolymer that accounts for nearly 30% of the organic carbon on Earth and is one of the few renewable sources of aromatic chemicals. As the most recalcitrant of the three components of lignocellulosic biomass (cellulose, hemicellulose and lignin), lignin has been treated as a waste product in the pulp and paper ...
Alireza, Rahimi, Arne, Ulbrich, Joshua J, Coon, Shannon S, Stahl   +3 more
openaire   +2 more sources

Application of the oxidative induction test to depolymerizing systems

Thermochimica Acta, 2001
Abstract Since the development of the oxidative induction time (OIT) test by former Bell Telephone Laboratories researchers, there have been many studies to broaden its applicability to polymers beyond the original polyolefins. The basic premise in OIT studies is that a detectable oxidation onset is based on the differential reactivity between the ...
Lecon Woo, Atul Khare, Henk P. Blom, Craig Sandford, Samuel Y. Ding   +4 more
openaire   +1 more source

Depolymerization of lignin by catalytic oxidation with aqueous polyoxometalates

Applied Catalysis A: General, 2013
Abstract In this work a method for the depolymerization of lignin by catalytic oxidation was studied. Using H 5 PMo 10 V 2 O 40 as the catalyst, various lignin spices including pyrolytic lignin, hydrolytic lignin, alkali lignin, sodium lignosulfonate and calcium lignosulfonate were tested for the oxidative degradation.
Yan Zhao, Qing Xu, Tao Pan, Yong Zuo, Yao Fu, Qing-Xiang Guo   +5 more
openaire   +1 more source

ChemInform Abstract: ANIL FORMATION BY OXIDATIVE DEPOLYMERIZATION

Chemischer Informationsdienst, 1973
AbstractWird das Oligomere (I) und Mesidin (IIa) in Benzol drei Tage in Gegenwart von Natriumbismutat gerührt, so erhält man das Anil (IIIa) (87%) und Azomesidin (IVa) (7%).
E. KON, E. MCNELLS
openaire   +1 more source

Depolymerization of Poly(2,6‐dimethyl‐1,4‐phenylene oxide) under Oxidative Conditions

Chemistry – A European Journal, 2003
AbstractDepolymerization of an engineering plastic, poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO), was accomplished by using 2,6‐dimethylphenol (DMP) under oxidative conditions. The addition of an excess amount of DMP to a solution of PPO in the presence of a CuCl/pyridine catalyst yielded oligomeric products.
Kei, Saito, Toru, Masuyama, Kenichi, Oyaizu, Hiroyuki, Nishide   +3 more
openaire   +2 more sources

Magnesium Oxide‐catalyzed Oxidative Depolymerization of EFB Lignin

Bulletin of the Korean Chemical Society, 2016
Empty fruit bunch (EFB) lignin, which had been isolated by the previous sulfuric acid treatment of EFB, was oxidized in the presence of a base and air to depolymerize the solvent‐insoluble lignin into smaller solvent‐soluble molecules. Depending on the types of base and solvent, the yield of solvent‐soluble lignin (SSL) varied, and the highest yield of
Vania Tanda Widyaya, Huyen Thanh Vo, Deliana Dahnum, Hyunjoo Lee   +3 more
openaire   +1 more source

Snapshots of lignin oxidation and depolymerization in archaeological wood: an EGA‐MS study

Journal of Mass Spectrometry, 2015
Evolved gas analysis‐mass spectrometry (EGA‐MS) was used for the first time to study archaeological wood, in order to investigate its chemical degradation. The archaeological wood was from an oak pile from a stilt house found in the Neolithic ‘La Marmotta’ village (Lake Bracciano, Rome, Italy).
Tamburini Diego, ucejko Jeannette Jacqueline, ucejko Jeannette Jacqueline, Ribechini Erika, Colombini Maria Perla, Colombini Maria Perla   +5 more
openaire   +4 more sources

A comparative study of secondary depolymerization methods on oxidized lignins

Green Chemistry, 2019
DDQ oxidized lignins were used as substrates to assess the effectiveness of secondary depolymerization methods for the production of aromatics.
Yang Song, Ali Hussain Motagamwala, Steven D. Karlen, James A. Dumesic, John Ralph, Justin K. Mobley, Mark Crocker   +6 more
openaire   +1 more source

Depolymerization during nitroxide‐mediated oxidation of native cellulose

Journal of Applied Polymer Science, 2007
AbstractThe kinetics and mechanism of depolymerization during nitroxide‐mediated oxidation of native cellulose has been studied under various conditions. The physical heterogeneity of the native cellulose and its complicated hypermolecular and supramolecular structure exerts a remarkable influence on the kinetics of oxidation and depolymerization.
Miloslav Milichovsky, Tomáš Sopuch, Jaroslav Richter   +2 more
openaire   +1 more source