Optional Procedure

Preparation Sign In atwww.cengage.com/login to answer Pre-Lab Exercises, access videos, and read the MSDSs for the chemicals used or produced in this procedure. Read or review Sections 2.3, 2.4, 2.9, 2.11, and 2.13. 

Apparatus A Pasteur pipet and apparatus for simple distillation, magnetic stirring, and flameless heating. 

Unless directed otherwise, return the distilled and undistilled cyclohexane to a bottle marked Recovered Cyclohexane.  

Sketch and completely label the apparatus required for a simple distillation. 

Why should you never heat a closed system, and how does this rule apply to a distillation  

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BASIC PROTOCOL 2 HPLC ANALYSIS OF REGIO- AND STEREOCONFIGURATION OF PRODUCTS In order to thoroughly characterize the LOX of interest, an optional procedure is offered to determine the regio- and stereospecificity of oxidation. For this purpose a reaction volume is used that is somewhat larger than that described in Basic Protocol 1 and the Alternate Protocol. The product hydroperoxides are reduced to their corresponding hydroxides, purified by TLC, methyl esterified, and separated by straight-phase HPLC followed by chiral-phase HPLC. In this way a complete structural analysis is obtained. 

It is by far the simpler method, gives a purer product, and is to be preferred to the displacement method. The directions given under procedure A are based essentially upon the results obtained by G. MePhail Smith and A. C. Bennett and involve the electrolysis of a saturated solution of barium chloride using a mercury cathode. The displacement method is given as an optional procedure. 

Note Steps 20 through 22 are an optional procedure to remove 210Po. To skip this demonstration, proceed to Step 23.)... 

Pre-shear (RPM) is an optional procedure for shearing of sample before measuring its yield properties. It is particularly useful if the user wants to eliminate previous shear histoiy (e.g., bumping, transferring) of the sample before testing and to observe the structural rebuilding of the sample. 

This is optional procedure, and the purpose is to inhibit ade-nylyl cyclase and reduce any basal chemotaxis signaling. The treatment also can be done with 1 mM caffeine for 30 min. We also point out that caffeine potentially inhibits many other cellular activities, including P13K and TOR kinase activity (36, 37). Thus one should consider the use of caffeine according to the aim of the experiment. Also one can examine the side effect of the caffeine treatment by using ACA null strain. 

An optional procedure is to use an aqueous solution of dimethylformamide and acetic acid (so called Eukitt) for clearance of the filter structure, after which it is dried by warming at 65°C for a few minutes before a drop of Euparal resin is applied and the coverslip is gently placed on top. 

Stereochemical Theory of Odor If performing any of the optional procedures, read as appropriate ... 

Two procedures are provided for preparing trans, fr ns-l,4-diphenyl-l,3-butadiene. In Experiment 39B, the reaction uses sodium ethoxide in ethanol solvent as the base, whereas in Experiment 39C, a green chemistry alternative is provided whereby potassium phosphate is employed as the base that is conducted without any solvent. The mechanism of the Wittig reaction in the presence of either sodium ethoxide or potassium phosphate is essentially identical. Sodium ethoxide is shown as the base in the mechanism that follows. In Experiment 39A, an optional procedure is provided for preparing one of the starting materials for the Wittig reaction. 

The matrix X represents the collected spectral data after optional procedures for preprocessing, such as normalization and column-centering. Each row of X corresponds to an object (sample), and each column represents a variable. Superscript t is used to imply transposition. Vectors are defined as columns so that transposition defines row vectors. 

As described briefly in Chapter 1, the more common typical chemical polymerization is relatively simple, involving monomer and an oxidant (usually also the dopant) in a suitable solvent medium, frequently aqueous, and temperatures in the region of -20 °C to 4-80 °C. Thus for instance, a 0.25 M solution of an oxidant such as ammonium peroxydisulfate ((NH4)2S20g) is added with stirring to a solution of 0.5 M aniline monomer in 0.5 M aqueous /7-toluene sulfonic acid solution (dopant electrolyte) at room temperature. As reaction temperature rises, the reaction bath is cooled with an ice-bath. After 2 hrs of stirring, the polymer is filtered, washed with dopant electrolyte solution, and dried in vacuo at 60 C. An optional procedure of Soxhlet extraction may be used for further purification. The polymer is then neutralized with 2 M NH4OH to yield the emeraldine base form of P(ANi). 

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