Oxidative addition chemistry of dimethyl(dipyridyl ketone)platinum(II)

2005 ◽  
Vol 83 (6-7) ◽  
pp. 595-605 ◽  
Author(s):  
Fenbao Zhang ◽  
Michael E Broczkowski ◽  
Michael C Jennings ◽  
Richard J Puddephatt
Keyword(s):  
Hydrogen Peroxide ◽  
Key Words ◽  
Acetyl Chloride ◽  
Oxidative Addition ◽  
Protonated Form ◽  
Supramolecular Polymer ◽  
Hydrolysis Of ◽  
Mecn Solution ◽  
Dipyridyl Ketone ◽  
Methyl Triflate

The dimethylplatinum(II) complex [PtMe2(DPK)] (DPK = di-2-pyridyl ketone) undergoes easy oxidative addition to give platinum(IV) complexes. For example, reaction of [PtMe2(DPK)] with MeI gave [PtIMe3(DPK)], reaction with N-chlorosuccinimide in methanol gave [PtCl(OMe)Me2(DPK)], and reaction with [FN(CH2CH2)2NCH2Cl][BF4]2 in MeCN gave [PtF(NCMe)Me2(DPK)][BF4]. In several cases, the ketone group of the DPK ligand took part in the reactions. For example, oxidation of [PtMe2(DPK)] by air or hydrogen peroxide gave [Pt(OH)Me2(DPKOH)] (DPKOH = κ3-NN′O-(2-C5H4N)2C(OH)O), which reacted with HCl to give [PtClMe2(DPKOH)] or with excess acetyl chloride to give [PtCl2Me2(DPK)]. Reaction of [PtMe2(DPK)] with methyl triflate in MeCN solution gave [PtMe3(NCMe)(DPK)][OTf], which reacted with more MeOTf in the presence of base to give [PtMe3{DPC(OMe)2}][OTf], where DPC(OMe)2 = κ3-NN′O-(2-C5H4N)2C(OMe)2. Hydrolysis of [PtF(NCMe)Me2(DPK)][BF4] gave [Pt{NHC(=O)Me}Me2(DPKOH)], which crystallized in partially protonated form as an unusual supramolecular polymer [Pt{NHC(=O)Me}Me2(DPKOH)]·0.5HBF4.Key words: platinum, oxidative addition, ketone, pyridyl.

Reactions in Activated Peroxide Systems and their Influences on Bleaching Performance

2020 ◽  
Vol 17 ◽  
Author(s):  
Xiaoyan Wang ◽  
Jinmei Du ◽  
Changhai Xu
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Energy Efficiency ◽  
Textile Industry ◽  
High Energy ◽  
Side Reactions ◽  
Competitive Reactions ◽  
High Energy Efficiency ◽  
Hydrolysis Of ◽  
Bleach Activators

Abstract:: Activated peroxide systems are formed by adding so-called bleach activators to aqueous solution of hydrogen peroxide, developed in the seventies of the last century for use in domestic laundry for their high energy efficiency and introduced at the beginning of the 21st century to the textile industry as an approach toward overcoming the extensive energy consumption in bleaching. In activated peroxide systems, bleach activators undergo perhydrolysis to generate more kinetically active peracids that enable bleaching under milder conditions while hydrolysis of bleach activators and decomposition of peracids may occur as side reactions to weaken the bleaching efficiency. This mini-review aims to summarize these competitive reactions in activated peroxide systems and their influence on bleaching performance.

Enzymatic colorimetry of lecithin and sphingomyelin in aqueous solution.

1983 ◽  
Vol 29 (8) ◽  
pp. 1513-1517 ◽  
Author(s):  
M W McGowan ◽  
J D Artiss ◽  
B Zak
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Amniotic Fluid ◽  
Enzymatic Reaction ◽  
Detergent Solution ◽  
Enzymatic Determination ◽  
Red Color ◽  
Hydrolysis Of ◽  
Zwitterionic Detergent

Abstract A procedure for the enzymatic determination of lecithin and sphingomyelin in aqueous solution is described. The phospholipids are first dissolved in chloroform:methanol (2:1 by vol), the solvent is evaporated, and the residue is redissolved in an aqueous zwitterionic detergent solution. The enzymatic reaction sequences of both assays involve hydrolysis of the phospholipids to produce choline, which is then oxidized to betaine, thus generating hydrogen peroxide. The hydrogen peroxide is subsequently utilized in the enzymatic coupling of 4-aminoantipyrine and sodium 2-hydroxy-3,5-dichlorobenzenesulfonate, an intensely red color being formed. The presence of a non-reacting phospholipid enhances the hydrolysis of the reacting phospholipid. Thus we added lecithin to the sphingomyelin standards and sphingomyelin to the lecithin standards. This precise procedure may be applicable to determination of lecithin and sphingomyelin in amniotic fluid.

Improving the efficiency of enzymatic hydrolysis of Eucalyptus residues with a modified aqueous ammonia soaking method

2018 ◽  
Vol 33 (2) ◽  
pp. 165-174 ◽  
Author(s):  
Dan Huo ◽  
Qiulin Yang ◽  
Guigan Fang ◽  
Qiujuan Liu ◽  
Chuanling Si ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Enzymatic Hydrolysis ◽  
Aqueous Ammonia ◽  
Pulp Mill ◽  
Fiber Surface ◽  
Raw Material ◽  
Sem Images ◽  
Aqueous Ammonia Soaking ◽  
Guaiacyl Lignin ◽  
Hydrolysis Of

Abstract Eucalyptus residues from pulp mill were pretreated with aqueous ammonia soaking (AAS) method to improve the efficiency of enzymatic hydrolysis. The optimized condition of AAS was obtained by response surface methodology. Meanwhile, hydrogen peroxide was introduced into the AAS system to modify the AAS pretreatment (AASP). The results showed that a fermentable sugar yield of 64.96 % was obtained when the eucalypt fibers were pretreated at the optimal conditions, with 80 % of ammonia (w/w) for 11 h and keeping the temperature at 90 °C. In further research it was found that the addition of H2O2 to the AAS could improve the pretreatment efficiency. The delignification rate and enzymatic digestibility were increased to 64.49 % and 73.85 %, respectively, with 5 % of hydrogen peroxide being used. FTIR analysis indicated that most syringyl and guaiacyl lignin and a trace amount of xylan were degraded and dissolved during the AAS and AASP pretreatments. The CrI of the raw material was increased after AAS and AASP pretreatments, which was attributed to the removal of amorphous portion. SEM images showed that microfibers were separated and explored from the initial fiber structure after AAS pretreatment, and the AASP method could improve the destructiveness of the fiber surface.

scholarly journals Bleaching of Microcrystalline Cellulose Produced by Gas-Phase Hydrolysis

2021 ◽  
pp. 173-183
Author(s):  
Alexander I. Sizov ◽  
◽  
Sergey D. Pimenov ◽  
Anastasia D. Stroiteleva ◽  
Katherine D. Stroiteleva ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Pharmaceutical Industry ◽  
Gas Phase ◽  
Sodium Hypochlorite ◽  
Microcrystalline Cellulose ◽  
High Rate ◽  
Subsequent Formation ◽  
Hydrolysis Of Cellulose ◽  
Yellow Tint ◽  
Hydrolysis Of

One of the main consumers of microcrystalline cellulose (MCC) is the pharmaceutical industry, where MCC is used as a binder and filler in direct compression of tablets. MCC is produced by acidic hydrolysis of cellulose, which usually results in a decrease in whiteness. This is due to the destruction of sugars formed during hydrolysis and the subsequent formation of colored products. The composition and properties of these products depend on the method of hydrolysis, acid concentration, temperature, and process duration. One of the most promising methods for producing MCC is gas-phase hydrolysis of cellulose with hydrogen chloride gas-air mixtures. The method has a high rate of hydrolysis, low reagent and energy consumption. The requirements of the pharmaceutical industry determine the need to produce MCC with high whiteness. The research purpose is to select bleaching modes for MCC using sodium hypochlorite and hydrogen peroxide as bleaching agents. MCC produced by gas-phase hydrolysis of bleached wood pulp was used during the study. The whiteness and intensity of the yellow tint of MCC in the bleaching process were determined by digital colorimetry on a flatbed scanner. The paper shows that sodium hypochlorite and hydrogen peroxide allow achieving the whiteness not less than 90 % and the intensity of the yellow tint not more than 3 standard units. High-quality bleaching can be carried out even for MCC samples with an initial whiteness of about 40 %. The most effective bleaching agent is sodium hypochlorite when the pH of the bleaching solution is 2–3. Hydrogen peroxide also provides high whiteness of MCC at pH of 10–11. However, the consumption of active oxygen (AO) for bleaching is more than three times higher in comparison with the consumption of active chlorine (ACh). It was found that the dyes of MCC produced by gas-phase hydrolysis consist of two chromophore groups that decolorize at different rates. The easily oxidized group of components makes up about 90 % of the total amount of dyes, and the resistant to oxidation components make up about 10 % and determine the intensity of the yellow tint of MCC. The modes of bleaching MCC with sodium hypochlorite and hydrogen peroxide to product samples with whiteness comparable to that of imported samples were determined. For citation: Sizov A.I., Pimenov S.D., Stroiteleva A.D., Stroiteleva K.D. Bleaching of Microcrystalline Cellulose Produced by Gas-Phase Hydrolysis. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 173–183. DOI: 10.37482/0536-1036-2021-6-173-183

A highly sensitive non-enzymatic hydrogen peroxide and hydrazine electrochemical sensor based on 3D micro-snowflake architectures of α-Fe2O3

RSC Advances ◽  
2016 ◽  
Vol 6 (65) ◽  
pp. 59907-59918 ◽  
Author(s):  
S. Majumder ◽  
B. Saha ◽  
S. Dey ◽  
R. Mondal ◽  
S. Kumar ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Electrochemical Sensor ◽  
Large Scale ◽  
Hydrothermal Reaction ◽  
Highly Sensitive ◽  
Hydrolysis Of

In the present work, well crystalline 3D micro-snowflake structured α-Fe2O3 has been successfully synthesized on a large scale via a simple hydrothermal reaction by hydrolysis of a K3Fe(CN)6 precursor.

Dry film for the enzymic determination of total cholesterol in serum.

1982 ◽  
Vol 28 (5) ◽  
pp. 1159-1162 ◽  
Author(s):  
G M Dappen ◽  
P E Cumbo ◽  
C T Goodhue ◽  
S Y Lynn ◽  
C C Morganson ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Cholesterol Oxidase ◽  
Comparison Method ◽  
Total Serum ◽  
Total Serum Cholesterol ◽  
Gelatin Layer ◽  
Control Fluid ◽  
Hydrolysis Of ◽  
Dry Film

Abstract We have prepared a dry film for the enzymic determination of total serum cholesterol. It consists of a transparent support bearing a buffered gelatin layer, and a white reflective spreading layer that contains all of the necessary components for the detection of cholesterol. The method is based on (a) hydrolysis of cholesterol esters to cholesterol by cholesterol ester hydrolase (EC 3.1.1.13), (b) oxidation of cholesterol to cholest-4-en-4-one and hydrogen peroxide by cholesterol oxidase (EC 1.1.3.6), and (c) oxidation of a triarylimidazole leuco dye with hydrogen peroxide in the presence of peroxidase (EC 1.11.1.7) to produce a dye with maximum absorption at about 650 nm. For use over a wider range of concentration, the dye density is read at 540 nm. With reflection densitometry and appropriate mathematical transformation, readings and cholesterol concentrations are linearly related to 5500 mg/L. Results correlate well with those by the Abell-Kendall comparison method (slope 0.97, intercept 92.5, correlation coefficient 0.974, Sy.x = 250.7), and the method is precise (CV of 1.2-2.3% for a control fluid and patients' samples) and relatively free of interferences.

Investigation of Alkaline Hydrogen Peroxide in Aqueous Organic Solvent to Enhance Enzymatic Hydrolysis of Rice Straw

2020 ◽  
Author(s):  
Jaruwan Damaurai ◽  
Thanchanok Preechakun ◽  
Marisa Raita ◽  
Verawat Champreda ◽  
Navadol Laosiripojana
Keyword(s):  
Hydrogen Peroxide ◽  
Enzymatic Hydrolysis ◽  
Organic Solvent ◽  
Rice Straw ◽  
Alkaline Hydrogen Peroxide ◽  
Hydrolysis Of
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