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CHM 207 Lecture Notes - Lecture 2: Silver Nitrate, Carbon Tetrachloride, Bromine

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lavendergiraffe572

30 Dec 2016

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University of Rochester

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Document Summary

Phenol: recrystallize from cyclohexane (changed from step 6) After recrystallization, label your crystals and allow them to dry in your drawer covered with parafilm punched with holes until next week (obtain mp and ir). Extract the organic layer with brine and collect organic layer and dry organic layer with mgso4. Gas chromatography: inject a sample that is volatile and so you can vaporize it and then the oven heats the sample up and see signal to show spectrum. Temperature programming: taking temp. of the oven and vary it but have the same temperature for each experiment or you will get inaccurate results and the heights/peaks will change. Nmr: (chemical shift, splitting and integration: how many protons) Gc response factor: a and b look like they are the same height but cannot tell the mole ratios just by looking at them (due to temperature variance and stationary phase differences). You have to calculate the response factor (in lab) on page 48-49.

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Related Questions

This is my lab procedure... please answer the following

1. Describe how the extraction is used to isolate the camphor.

2. Describe the reaction occurring and explain the catalytic cycle involving NaClO.

2. Add 1.0 g (6.5 mmol) of borneol, then 4 mL of ethyl acetate and a magnetic stir bar to the round bottom flask. 3. Stir the mixture until the solid dissolves using the stir bar. While stiring, add 0.08 g sodium chloride and 1.5 mL of distilled water to the flask 4. Add 20 ml of bleach to the separatory funnel. Make sure the stop cock is closed to start with 5. Next add the bleach solution to the reaction mixture in small portions with while stirring for a period of 10 minutes or more Monitor the temperature to control the rate of addition so that the temperature remains below 50Â°C. Have an ice water bath nearby to cool the reaction mixture if it begins to approach 50Â°C. When the addition is complete, seal the flask with Paraflim and stir for 30 minutes or more 6. Continue to stir the mixture for 50 minutes at room temperature, then add another 0.03 g sodium chloride 7. Stir for a further 10 minutes, then add 15 mL distilled water 8. Add a "spatula tip of sodium bisulfite to reduce any unreacted NaCIO, then test the aqueous layer with starch-iodide paper: a blue-black color indicates that more sodium bisulfite is needed 9. Separate the layers using a separatory funnel. Drain the lower (aqueous) layer into a 50 mL Erlenmeyer and label it as flask A this is to be extracted further. Pour out the upper layer (ethyl acetate) into another 50 mL Erlenmeyer and label as flask B; this 10. Return the aqueous layer (from flask A) to the separatory funnel and extract three more times with 5 mL of ethyl acetate. Each 11. Now return the organic layer (in flask B) to the separatory funnel and extract this organic solution with 5 mL saturated sodium 12. Dry the organic layer in flask B further by adding some crystals of using sodium sulfate. Transfer the dried solution (by will be used to hold the organic extracts time put the upper organic layer into flask B, until you end up with one big organic extract chloride solution, placing the lower layer into flask A and the upper organic layer into flask B decanting) into a pre-weighed (labeled) 50 mL beaker and let it dry in the fume hood for 30 minutes. You should be left with a final white powder product of camphor. Weigh the flask to determine the amount of crude wet product. 13. Allow your product to dry (preferable in a desiccator) overnight and reweigh it the next day. Use the weight of the dried/purified product to determine the % yield 14. Assess the purity of the final product using FTIR spectroscopy

Organic Chemistry lab QUESTIONS Extraction of Caffiene Lab

â¢Procedure

1) Use hot water to extract the caffeine from the tea leaves.

- tannins and chlorophyll will extract along with caffeine

2) Use dichloromethane to extract caffeine from water using extraction

techniques from last weeks lab.

- dichloromethane is more dense than water and will be the

bottom layer in the separatory funnel.

- perform 3 x 20 mL extractions with dichloromethane

3) Wash the 2 x 20 mL 6M NaOH solution with base to remove acidic

tannins. Tannins will deprotonate and preferentially partition into

the aqueous phase.

4) Dry organic phase with drying agent (CaCl2) to remove residual water.

5) Transfer dichloromethane to flask and evaporate in hood.

6) Recrystallize caffeine from 2mL hexanes and 0.5 mL acetone. Filter, mass product and determine % by weight of caffeine from tea.

7) Analyze for purity via TLC and compare to that that extracted from coke and pure caffeine..

PROCEDURE TO DO Â· Weigh benzocaine isolated from last day and record the mass in the raw data from last day Determine experimental melting point of benzocaine sample and record the melting point in Dispose of benzocaine sample in appropriate dump bottle. Caution: All concentrated acids, particularly conc. sulfuric acid, will burn the skin. Handle them carefully (wear gloves) and wash up immediately if you spill any on your hands. NOTE: Wash the graduated cylinder used to obtain the acid (with cold water) to remove all traces of sulfuric acid Weigh a 4.0 g sample of salicylic acid and place it in a 50 mL round bottom flask (along with some boiling stones). Make sure that there is no solid material trapped in the neck of the round bottom flask. In a dry 50 mL Erlenmeyer flask, place 10 mL of methanol and (while cooling the flask in an ice- water bath) slowly add 4 mL of concentrated (18 moL) sulfuric acid while swirling. This solution wil become very hot, therefore the addition must be done slowly. Pour the methanoW/acid mixture into the round bottom flask which contains the salicylic acid. Attach a reflux condenser and reflux the mixture for 30 minutes using a heating mantle and variac (set at-80% to start then reduce to 40-50%). The reflux must be monitored to ensure that the reflux line does not become too high. If the reflux line is too high, the product may escape from the condenser.During this reflux, the product will be visible as a small layer on top of the methanol/acid mixture. After the reflux is finished, shut off the variac and remove the heating mantle to allow the reaction mixture to cool to room temperature for a few minutes and then place an ice-water bath around the flask to cool for 4-5 minutes. Pour the chilled reaction mixture into a 125 mL Erlenmeyer flask which contains 10 mL of cold water and then rinse out the round bottom flask with a second 10 mL portion of water and add this to the Erlenmeyer flask also. Pour the resulting mixture into a separatory funnel (do not allow the boiling stones into the separatory funnel). Rinse the reaction flask (50 mL RBF) with 20 mL of ethyl acetate and pour this into the separatory funnel (do not allow the boiling stones into the separatory funnel). Rinse the Erlenmeyer flask with 20 mL of ethyl acetate and add this to the separatory funnel also. Shake the funnel with venting and after the layers have separated, drain the lower layer (methanol & sulfuric acid). The lower layer contains concentrated sulfuric acid and can be disposed of as follows. Pour the lower layer into a large volume of water in a beaker, stir to mix and then dispose of it down the drain in the fume hood followed by a copious amount of water