How to analyze the result of UV light spectrum for 1,4-Diphenyl-1,3-Butadiene. Wittig reaction lab?

The trans, trans isomer absorbs at 328 nm and possesses fine structure, and the cis, trans isomer absorbs at 313 nm and has a smooth curve. My results are 2.264 A for 313 nm, and 2.313 A for 328 nm. What do these two numbers mean??

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Reid WolffLv2

13 Dec 2019

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1)for this experiment, if applicable, what is the theoretical yield, balanced chemical equation, and mechanism? Please also provide a flowchart of the procedure

of the trans, trans product? Report the resuits that you obtain, including R values and the appearance ot the pots under illumination. Discard the trae n h-container desgrated for nonhalogenated waste Yield Calculation and Melting-Paint Determination. When the trans,trans-1,4-dipheny i-dry, determine the melting point [literature. 162-c} woigh the solid and 1. 3-butadi ne datormine the percentage neld it tha mening point iÂ§ below t45Â°C, recrystalizoÂ·portion of the compound from hot 95% ethanol pledatormine the meiting point Optional Exercise: Spestroscopy. Obtain the proton NMR spectrum in CDCl, or the UV spectrum in hoxane. For the UV spectrum of the product, dissolve a 10-mg sample in 100 mL of hexane in a volumetric flask Remove 10 mL. of this solution and dilute it to 100 mL in enother volurmetic flask. This concentration should be edequate for analysis. The trans trans orner nbsorbs at 328 nm and possesses fine structure., and th@ Cis.trans somer absorbs at 313 nm and has a smooth curve See d your spectrum is consistent with these observa tions Submit the spectral data with your laborstory report C. Solventiess Preparation ofReaction. Using an analytical baiance 1,4-Diphenyl-1,3-Butadiene chlonide and 850 mg of potassium phosphate (tribasic, K,PO,) and place the solids into a clean and dry 6-cm criside diameter) porcelain mortar with pour tip. Using an automatic pipet. measure and add 100 Î¼ãof cinnamaldehyde to the mixturo in the mortar Grind the mixture together for a total of 20 minutes. It is much easier to use a pestle that is long anough to grip securely in your hand, thus keeping one's fingors from getting sore or tired. At the beginning of the grindng operation, the mixture wit act lice putty and have a definite yellow coloer. Alter a feww minutes of grinding the mixture will start to turn into a thick paste that adheres to the inside of the mortar and the edges of the pestle. Bend the and of a spatula as shown in the fig ure. This bent spatula is useful for scraping the material off of the inside of the mortar and pas te and directing the mass into the center of the mortar. Repeat the scraping operation after every 1 to 2 minutes of grinding Indlude that time in the total of 20 minutes of grinding time Start Isolation of Crude 1,4-Diphenyl-1,3-Butadiene. After 20 minutes, add a few milliliters of deionized water to the material in the mortar Scrape the mortar and pestle a final time to oosen all of the product from the mortar. Pour the mixture into a Hirsch funnel inserted into a filter flask under vacuum. Use a squirt bottle with deionized water to transfer any remain- ing off-white product into the Hirsch funnel. Discard the filtrate that contains potassium phosphate and some triphenylphosphine oxide. The oft-white solid consists mainly of the trans, trans isomer, but some of the cis, trans isomer will be present as well. Crystallization. Purify the off-white solid by crystallization from absolute ethanol in a small test tube using the standard technique of adding hot solvent until the solid dissolves A small amount of impurity might not dissolve. If this is the case, use a Pasteur pipet to rap- dly remove the hot solution from the impurity and transfer the hot solution to another test tube. Cork the test tube and place it in a warm 25-mL Erienmeyer flask. Allow the solution to cool slowly. Once the test tube has cooled and crystais have formed, place the test tube in an ice bath for at least 10 minutes to complete the crystallization process. Place 2 mL of absolute ethanol in another test tube and cool the solvent in the ice bath (this solvent will be used to aid the transfer of the producti. Loosen the crystals in the test tube with a micro- spatula and pour the contents of the test tube into a Hirsch funnel under vacuum. Remove Pinkard, J. H; Wille, B,; Zechmeister, L. The Comparative Study of the Stereoisomeric 1,4-diphenyl-1, 3-butadienes.J. Am. Cheam. Sc. 1948, 70, 1938

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