Why are so many analytical chemists switching to MC&B?
Formation in Dime ;ypropane-lndu of Dimethyl Sulfoxide Reagents. 2,2-Dimethoxypropane obtained , from Eastman Organic Chemicals and redistilled from 78° to 80° C. Methanolic HC1 was prepared every two days by bubbling dry HC1 into methanol until the concentration was 10% by weight. Methanol was spec-
troquality from MathesonColeman & ^^uxnercnemicals were re Procedure. Appropriate amounts of dimethyl sulfoxide were added to each of five tubes containing 0.5 ml. of D M P , and the volume in each tube was adjusted to 5 ml. with 1 0 % methanolic HC1 to give the following dimethyl sulfoxide concentrations: 1%, 0.5%, 0.25%, 0 . 1 % , and 0.05%. A sixth tube contained 0.5 ml. of t>MP and 4.5 ml. of 10% methanolic HÇL but no dimethyl sulfoxide. Col
I^TFiethanolamine
(Mauy^oi^^Xjulg-
i ^ ^ S T u e c i a W u mm., and ihe fraction boiling at 185-7° C. was collected. The concentration was determined by pH titration. All other chemicals were
ther Sociel
"sed
throu
bottli PHENYL ISOCYANATE, reagent
boiling point 60° to 62° C./2(
The phototube was connected minutes over an eight-hour period xoammeter to a Varian G-10 a microammf wavelength of 525 m^i. to 50 ml. of dry toluene, dilute ρ recorder. ml. with additional toluene, an Two special mixtures were teagents. Anthracene was prepared for gas chromatogrs ared from anthraquinone by the thoroughly. Store in the volu follows: Mixtures containing method of Fieser (S) and was purified flask. If any crystalline preeipi each of octanoic, decanoic, ani by recrystallization and zone refining. formed the reagent is discarded, acids were placed into two se£ Naphthaeene ( J ^ y ^ ^ ^ ^ T u l r m P " * k ALCOHOLS used as standards ml. reaction flasks. T h e at H e O ù ^ û S 2 ) wasuseTlwifnfflrW 7agent grade chemicals. dissolved in 4.5 ml. of 10% m Srrmcauon^*All solvents used were ÏCATALYST. Add 0.404 gram o! H O , and 0.5 ml. of D M P u spectroquality grade. ' ~ ' e (catalyst T-9 from to each tube; finally 0.01a h ^ D n i K of drv t< Procedure. Standard solutions of !J dimethyl g--"-w a s ι ^ measurements were cibility or the above > the hydrochloiflipWIIPWPW^i^lBffuPlfcm an ethanoliting monoc" hyl acetate mixture. p-Tyramine hydrochloride (Distillation mperatures was deterroducts) was reerystallized f an ethanol-ethyl acetate _ _ -u- to 60-mesh, reagent ; lillji}^·'· ixture. Hordenine sulfate J -ë calcium oxalate monohydrate »- and DL-metanephrine v'druohlorkk^ were obtainec^ obtained from Matheson C o l e m a n & '""'·'— --« -atol Labor Bell Co. The « B i p W I i f P H W i e W S t K ^ W J J J ^ i g h t loss point for the oxalate rç»>" to carbonate decomposition. The confidence limits for the mean temperature based on 6 measurements a t the nee limits was found to μ">—
73E23
Wé asked them. Here are some of the answers.
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