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Nonconjugated Symmetrical Dienes
Published in George B. Butler, Cyclopolymerization and Cyclocopolymerization, 2020
Radical cyclopolymerization of N-propyldimethacrylamie has been reinvestigated. Kinetic orders of the polymerization rate with respect to the monomer and the initiator were 1.0 and 0.5, respectively, at concentrations greater than 1.6 M. Absolute values of rate constants of propagation and termination reactions were determined by the rotating sector method in bulk and in 50% acetonitrile solution at 30°C. The polymer consisted of five-membered cyclic repeating units almost exclusively. The rate constants for the addition of polymer radical to vinyl monomers and those for the addition of polymer radicals to N-propylmethacrylamide were also evaluated. On the basis of the rate constants obtained, the rate-determining step of propagation was the intermolecular addition of the growing radical to the monomer. The growing radical, formed by intramolecular addition to C:C of the same molecule was as reactive as polymer radicals from resonance-stabilized monomers. The five-membered ring formation was highly favored by the conformation of the monomer, in which coplanarity of the newly formed bond and the semi-occupied orbital of the new radical center was readily achieved. Relatively low reactivity of the polymer radical was accounted for by delocalization of the unpaired electron on the coplanar three carbon atoms. Radical addition of 2-methyl-2-propanethiol to the monomer gave only the substituted succinimide. The five-membered ring formation in the addition reaction was due to the favorable conformation of the monomers87
Nanosensors for the Food Industry
Published in V. Chelladurai, Digvir S. Jayas, Nanoscience and Nanotechnology in Foods and Beverages, 2018
V. Chelladurai, Digvir S. Jayas
Wang et al. (2008) developed an immunosensor with titanium dioxide (TiO2) nanowire bundle to detect L. monocytogenes using electrical impedance in the circuit. A TiO2 nanowire bundle was placed between gold electrodes, and the electrodes were coated with 2-methyl-2-propanethiol (SH−nCH2)3−CH3) in order to avoid cross binding with antibodies. Then monoclonal L. monocytogenes antibodies were placed on TiO2 nanowire bundle, which captured the L. monocytogenes from the samples (Figure 4.6A). Due to the antibody–antigen reaction, increase in electrical impedance was noticed in the circuit, by which L. monocytogenes presence in the sample was detected (Figure 4.6B). Using this sensor, L. monocytogenes can be detected in 50 min, at a concentration level of 4.7 × 102 cfu/mL. Wang et al. (2008) also found there was no interference from other foodborne pathogens (E. coli O157:H7, S. aureus, and S. typhimurium) on L. monocytogenes detection using this immunosensor.
Axillary Odour Formation and Retention: The Role of Textiles Fibers and Fabric Structure
Published in G. Thilagavathi, R. Rathinamoorthy, Odour in Textiles, 2022
R. Rathinamoorthy, G. Thilagavathi
PTR-MS analysis performed to evaluate the adsorption and emission capabilities of cotton, polyester, and wool fiber against nonanal, 2-propanethiol, dimethyl disulfide (DMDS), and benzaldehyde. Their results confirmed that the sorption characteristics of fiber strongly depend on its chemical nature. Three different mechanisms were proposed for the selected three fibers.
Efficient passive sampler using copper oxide micro-adsorbent for the detection of volatile sulfur compounds (VSCs) from the small lab-scale spilled crude oil
Published in Petroleum Science and Technology, 2022
Hozan Jalal Saleem, Yousif Mustafa Salih, Luqman Omar Hamasalih, Khalid M. Omer
All chemicals used throughout this work were of pure and high-quality grade. 2-Propanethiol (98%), Allyl methyl sulfide (98%), 2-Butanethiol (99%), 2-methyl-2-propanethiol (99%), 1-Propanethiol/polymercaptan (98%), 3-Methylthiophene (99+ %), 2-Methylthiphene (98%), 1-Octanethiol/octylmercaptan (97%) (ACROS/ORGANIC), Copper nitrate trihydrate (99%), Sodium hydroxide (98%), Benzene (99.9%) and activated charcoal (0.3–0.5 mm) 35–50 mesh ASTM were all purchased from Merck (Merck, Germany).
Ground solid permanganate oxidative coupling of thiols into symmetrical/unsymmetrical disulfides: selective and improved process
Published in Journal of Sulfur Chemistry, 2022
Ngan-Giang Thi Nguyen, Xuan-Triet Nguyen, Ngoc-Huy Nguyen, Thi Xuan Thi Luu, Xuan-Tien Dao
Finely ground solid potassium permanganate (1 mmol, 0.158 g) was added slowly into a 5 mL round bottom flask containing 2-methyl-2-propanethiol (1.5 mmol, 0.135 g) and 1-octanethiol (1.5 mmol, 0.219 g) over 5 min. The reaction mixture was then stirred for two and half hours at room temperature. Subsequently, the reaction mixture was worked up as described in method A.