The Experts below are selected from a list of 30 Experts worldwide ranked by ideXlab platform
Brent Walton - One of the best experts on this subject based on the ideXlab platform.
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Potentiometric titration of long chain Tertiary Amine Oxides and Tertiary Amines using a poly(vinyl chloride) membrane electrode
The Analyst, 1994Co-Authors: Brent WaltonAbstract:Two separate potentiometric titrations are used to quantify mixtures of long chain Tertiary Amine Oxide and Tertiary Amine as their cations. A direct titration of the mixture in water at pH 2 against a standard sodium lauryl sulfate solution, using a poly(vinyl chloride) membrane sensing electrode, determines the total surfactant content, reported as % m/m Tertiary Amine Oxide. A simple extraction is used to separate the Tertiary Amine, which is subsequently titrated under the same conditions. This titration is quantitative for dimethylalkylAmine Oxides and their corresponding Amines (where alkyl = C10–C16). Seven analyses are performed on an aqueous mixture and give the following results: Tertiary Amine Oxide, 23.8 ± 0.1% m/m and Tertiary Amine, 1.0 ± 0.1% m/m, at a 95% confidence level. This method is capable of determining Tertiary Amine at 0.1% m/m in the presence of 25% m/m Tertiary Amine Oxide with no interference. The same aqueous mixture is spiked with Tertiary Amine to test the quantitative recovery of the Amine. The recovery is 3.1% m/m compared with an expected value of 3.2% m/m Amine.
Yu Chen - One of the best experts on this subject based on the ideXlab platform.
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Core-shell type hyperbranched grafting copolymers: Preparation, characterization and investigation on their intrinsic fluorescence properties
Polymer, 2016Co-Authors: You Fan, Ya-qian Cai, Yefeng Yao, Yu ChenAbstract:Abstract Hyperbranched polyethylenimine (HPEI) was modified with glycidol, resulting in hydroxyl terminated HPEI (HPEI-OH). Subsequently, HPEI-OH was used as the macroinitiator to initiate the anionic ring-opening polymerization of glycidol, realizing the hyperbranched grafting copolymer with HPEI as core and hyperbranched polyglycerol (HPG) as shell (HPEI- g -HPG) through the 'grafting from' method. The diagrams from gel permeation chromatography (GPC) showed that the products were a mixture of copolymers and homopolymers. A two-step purification method was developed to separate HPEI- g -HPGs from the mixture, which was much more effective than the normally-adopted dialysis method. The hyperbranched grafting polymerization condition was optimized and the maximal grafting efficiency was found to be ca. 30%. Under the optimal grafting polymerization condition, we prepared a series of HPEI- g -HPG copolymers that have the same HPEI core, but have a different number of glycidol units in the HPG shell. The detailed structural information of these copolymers was deduced from 1 H NMR, inverse gated decoupled 13 C NMR and GPC measurements. Although no traditional fluorophores existed in HPEI- g -HPGs, HPEI- g -HPGs could emit blue fluorescence centered at ca. 470 nm. The fluorescence intensity was influenced pronouncedly by the thickness of HPG shell, pH, oxidation time, the amount of THF in the solvent mixture. The detailed characterizations and analyses supported that the luminogen of HPEI- g -HPGs was Tertiary Amine Oxide.
Wu Kun Fan - One of the best experts on this subject based on the ideXlab platform.
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A Laser-Imageable Thermo-Sensitive Film Based on Tertiary Amine Oxide-Containing Resin
Advanced Materials Research, 2010Co-Authors: Wu Kun FanAbstract:A modified phenolic resin containing Tertiary Amine Oxide was prepared via a two-step method. Epoxy phenolic resin, F-48, was reacted with dimethylAmine to give the phenolic resin containing the Tertiary Amine group, which was then oxidized with hydrogen perOxide to obtain the target product. The Tertiary Amine Oxide-containing resin could easily dissolve in water. However, it became water insoluble after heat treatment at a high temperature such as 160 °C. Thermal properties of the Tertiary Amine Oxide resin were studied with DSC and TGA. A thermo-sensitive film comprising the prepared resin and an IR-dye was prepared and laser-induced thermal imaging was also conducted. This material might be used to develop new chemistry-free printing plates.
S. A. Panichev - One of the best experts on this subject based on the ideXlab platform.
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Phase Transfer of the Organic Substrate in the Epoxidation Reaction of Allyl Chloride in Two-Phase Aqueous–Organic Systems
Petroleum Chemistry, 2018Co-Authors: L. P. Panicheva, G. P. Meteleva, O. V. Ageikina, S. A. PanichevAbstract:The mechanism of synergism for mixtures of phase-transfer carriers QХ with Tertiary Amines and pyridine in the epoxidation reaction of allyl chloride has been established. It has been shown that Tertiary Amines (triethylAmine, tributylAmine, N,N -dimethylaniline, and N -methyldiethanolAmine) and pyridine oxidizable in situ to N -Oxides promote the transfer of the organic substrate (allyl chloride) to the interface (PB). It is assumed that the synergism of mixtures of phase-transfer carriers QХ with a Tertiary Amine Oxide or pyridine Oxide can also be due to the formation of a mixture of two catalysts, Q_3[PW_4O_24] and WO(O_2)_2L (where L = a Tertiary Amine Oxide or pyridine Oxide). The WO(O_2)_2L complex will provide the stage of reoxidation of the complex Q_3[PW_4O_24 −_ х ] in the organic phase and, hence, the possibility for the development of the process of epoxidation not only at the interface but also in the bulk of the organic phase. The maximum coefficient of synergistic effect ( k _s = 2) is observed for a mixture of cetylpyridinium bromide (90 mol %) and pyridine N -Oxide (10 mol %).
Li Zhongxiao - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and properties of a water-soluble thermo-sensitive resin with Tertiary Amine Oxide substituents in the side chain
Polymer Bulletin, 2015Co-Authors: Pu Jialing, Li ZhongxiaoAbstract:This paper was focused on the synthesis and properties of a water-soluble resin having Tertiary Amine Oxide side substituents. First, 3-(dimethylamino)propanoic acid was synthesized through the addition reaction of dimethylAmine with methyl acrylate, followed by hydrolysis of the adduct. Then, 3-(dimethylamino)propanoic acid was oxidized with hydrogen perOxide to obtain 3-(dimethylamino)propanoic acid Oxide. Finally, epoxy phenolic was reacted with 3-(dimethylamino)propanoic acid Oxide to get the end product. Thermal behaviors and thermo-induced solubility change of the prepared resin were investigated. It was found that the Tertiary Amine Oxide resin was still water soluble even after heating at 120 °C for 1 h. However, it readily became completely water insoluble after heating at 170 °C for a short period of time. Thin films were prepared with the aqueous solution of the Tertiary Amine Oxide resin and an infrared (IR) dye with maximum absorption at 830 nm. The films could absorb 830 nm IR imaging radiation and give negative image after developing with neutral water. The water-soluble thermo-sensitive resin might be used in chemical-free thermal laser imaging applications.