chemsample-lab2-methods

Conducted by: Student A + B The following procedure was conducted using double the amounts of quantities listed in the general lab manual protocol – “Diels-Alder Reaction, pg. 62.” Note also, that we as a group ran //two vessels// (of the exact same quantities) through the MARS microwave ... over a two week time period. Keep this in mind when reading through the protocol - which we have designed to be read as if only one vessel was being prepared, and run through the experimental process ~
 * __Diels-Alder Reaction of 2,3-dimethyl-1,3-butadiene & Maleimide (Double Quant)__**

//1)// First & foremost, gathering and preparing the vessel (with all reagents to undergo microwave reaction) had to be done. As a bullet list, this is what was done: - Obtained reaction vessel, and cleaned it with soapy water, a scrubby brush, and acetone.  - Prepared ~ 1.70g maleimide, 5.0 mL water, & 4.0 mL 2,3-dimethyl-1,3-butadiene in a reaction vessel.   - Sealed the vessel with cap and screw-on top.

 //2)// Due to a lack of magnetic stir bars, thereafter, the lab was postponed to the following week.

 //3)// The following week, when lab resumed, the preserved vessel (from above) was run through the Mars microwave, set for “Diels-Alder...” - The microwave ramped up to 110 deg/c for five minutes, remained there for 5 more minutes, and then cooled for approx. ten minutes. //See the video link ...//

 //4)// When the reaction was complete, the vessel was removed from the microwave and cooled to room temp (25 deg/c).

 //5)// A vacuum filtration apparatus (previously prepared) was then used to filter and dry the solidified organic product.

 //6)// Finally, the product was removed from the vacuum filtrator, weighed on a digital scale (to calculate dry mass/yield), and stored in a small storage tube. A small sample was used to determine the products melting point, from which it could be compared to literature values – leading to possible conclusions as to its chemical structure.

 //7)// Following the above (and still to come) is a chemical analysis of the product using Infrared Spectroscopy. This will be accomplished in the following week of Orgo Lab.

**__Diels-Alder Reaction of 2,3-dimethyl-1,3-butadiene & Maleimide (Regular Quant.)__**  Conducted by: Student C + D

 We added 0.853 g of maleimide and 2.00 g of 2,3-dimethyl-1,3-butadiene to microwave reaction vessel. Because there were no stir bars the first laboratory day, we left the tubes to sit for a week. The next week we added the stir bars and placed in the microwave at a pre-designed schematic. This had the microwave (called MARS) heat the vessel to 100 degrees for 5 minutes and then hold it at that temperature for 5 minutes. We then allowed our vessel to cool after being taken out of the microwave.

 The product was washed with dichloromethane. We then set up a vaccuum filtration apparatus to separate the product from this dichloromethane. The product was checked three times for melting temperature, twice in the automatic machine and once in the mel-temp.

 **__Diels-Adler reactio​n of 2,3-dimethyl-1,3-butadiene & dimethyl fumarate (Regular Quant)__**  Conducted by: Student E + F

 2/4/10  1. My partner and I weighed out 0.422g dimethyl fumarate, then added 1.05 mL 2-3-dimethyl-1-3-butadiene. The total volume of our liquid was equal to 5.0mL - this needs to be consistent with the other samples going into the microwave. Make sure you have your magnetic stirrer in and then add water for the missing volume.

<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;"> Note: We were unable to find stir bars so the lab was postponed until 2/11/10. The mixture sat in the sealed vessel for a week.

<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;"> 2. Then we placed our mixuture into the Mars Microwave. The microwave was set up by Mary. It ran for 5 minutes to reach 140 degrees C, then it sat at 140 degrees C for another 5 minutes, and finally it took 10 minutes to cool down. Unfortunately, the vessels sat in the microwave for 20 minutes without it on, so we tried the process again. Another 20 min later the product was placed into a rotary evaporator and washed with 5mL dichloromethane. This device gets rid of solvents within the mixture (It is quite crucial that you repeat this step two more times, otherwise your overall product will not be as pure).

<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;"> 3.After this process of evaporation of the solvent happens, there will be two layers that appear. The clear layer is the inorganic one which you discard into another beaker. Since we were using the rotary evaporator we were able to discard the inorganic material in one, easy step. We repeated this process two more times, both with 5 mL dichloromethane. We also added 5 mL of distilled water to the funnel.

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<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;"> Note: We ran out of time on 2/11/10, and will finish and continue this on 2/18/10.

<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;"> 4. On 2/18/10 Student E tried testing melting point as student F began the next lab. Melting point was never found because the product had a lot of salt in it, and the melting point was at or above 300 degrees C.

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<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;"> 4. From there we needed to test the I-R.

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