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Amidation of Methyl Esters with Formamides in the Presence of KCN as the Catalyst
Published in John R. Kosak, Thomas A. Johnson, Catalysis of Organic Reactions, 2020
A. Benderly, L. Y. Dennis, A. Bravo
In a 50-mL round-bottom flask equipped with magnetic stirring bar, thermometer, and a condenser-drying tube system were placed 1 g (0.015 mol) of dry KCN, 10 g (0.075 mol) methyl hexanoate and 10.5 g (0.19 mol) of N-methylformamide. The heterogeneous mixture was heated at 130°C with vigorous stirring for 4 h. GC analysis indicated 100% conversion. The reaction was then cooled to 10°C which resulted in separation of 0.85 g of KCN. After the filtration of the catalyst, 25 mL of MeOH was added and the solution was treated with activated carbon, filtered, and concentrated under vacuum. Excess N-methylformamide was recovered by bulb-to-bulb distillation (90°C, 1–5 mm Hg). The residue was distilled at 195° (195°C/95 mm Hg) resulting in 8.5 g (85%) of colorless liquid. 1H NMR (CDCl3-TMS) δ 6.7 (s, br, 1H), 2.8 (d, 3H), 2.4–2.1 (m, 2H), 1.7–1.1 (m, 6H), 1 (t, 3H); mass spectrum, m/e 129, 114, 110, 86, 73 (100%), 58. Anal, caled., for C7H15NO: C, 65.50; H, 11.70; N, 10.08. Found: C, 64.95; H, 11.54; N, 10.14.
Polypeptides
Published in Stanislaw Penczek, H. R. Kricheldorf, A. Le Borgne, N. Spassky, T. Uryu, P. Klosinski, Models of Biopolymers by Ring-Opening Polymerization, 2018
l-Ala-NCA (5.75 g, 50 mmol) is dissolved in 80 ml of dry acetonitrile and 0.7 ml of a 1 M solution of n-benzylamine in dry 1,4-dioxane are added under stirring or shaking. The reaction vessel is closed with a freshly prepared calcium chloride drying tube. After 4 h, the reaction mixture is diluted with 120 ml of acetonitrile or THF and filtered with suction. The filter cake is washed with diethyl ether and dried at 50°C/12 mbar. The yield is in the range of 95 to 98%, the DP¯n around 7 and the secondary structure is almost completely β fished.
Common Acid, Alkali, and Other Standard Solutions
Published in James P. Lodge, Methods of Air Sampling and Analysis, 2017
When large quantities of solutions are prepared and standardized, it is necessary to provide protection against changes in normality due to absorption of gases or water vapor from the laboratory air. As volumes of solution are withdrawn from the container, the replacement air should be passed through a drying tube filled with equal parts of 8 to 20-mesh soda lime, oxalic acid, and 4 to 8-mesh anhydrous calcium chloride, each product being separated from the other by a glass wool plug.
Experimental investigation on air dehumidification performance of metal organic frameworks and its application potential for solid desiccant air conditioning systems
Published in Science and Technology for the Built Environment, 2023
Jinzhe Nie, Yuxin Pang, Jilei Liu, Xiangrui Kong, Han Zhang
The gas generating part includes drying tube, reagent tube and saturation tube. The drying tube is used to remove moisture and impurities from the carrier gas. The reagent tube is connected to a bottle with liquid adsorbate, and generates gaseous (moisture in the conducted experiments) through heating. The saturation tube is submerged in a thermostat water bath at experiment designed temperature, and the moisture condenses at certain temperature to get water vapor saturated air.