Metal Acetylacetonate complex lab PDF

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Experiment 4 Report

Na me :Emi l yDr e nt h

Pa r t ne r :Ni c o l aEr i k s e n

St ud e n tNo :2 0 1 05 4 3 7

St ud e n tNo :2 0 0 98 8 5 9

La bSe c t i on :2 0 6 b0 0 9

Be n c h#( o nc o mp u t e rs c r e e n ) :4 0

Experiment 4. (2 weeks) (LSM) Metal Acetylacetonate Complex Purpose Part 1: The purpose of this lab was to use inorganic synthesis techniques to prepare Fe(acac)3. Part 2: The purpose is continued from part one and the melting point is determined after the complex is recrystalized as well as the percent yield is recalculated.

Introduction In this experiment you need to understand that metal ions can bind with neutral atoms, a ligand, which forms a coordination complex. This occurs between acetylacetone and β diketone which make the acetylacetonate anion. Refer to figure 23 in the first year laboratory manual [1]. Then the acetylacetonate anion is able to connect to the metal ion Mx+ making it stable as seen in figure 24 in the first year laboratory manual [1]. In the specific experiment this knowledge is used because the acetylacetonate ion bonds with iron (III) to make octahedral Fe(acac)3. The molecular mass of ferric chloride hexahydrate must be known and is 270.28 g/mol, as well as acetylacetonate which id 100.11 g/mol and tris(acetylacetonate) iron (III) which is 353.16 g/mol. Health hazards of acetylacetone include harmful on contact with the skin or swallowed, respiratory tract irritation, skin irritation, eye irritation, central nervous system depression [2]. Also the balanced equation used is FeCl3+3CH3COCH2COCH3  Fe(CH3COCHCOCH3)3+3HCl+6H2O

Procedure Synthesis of Fe(acac)3

Reference lab manual pages 63-64 for more details. 

Wear protective gloves throughout this experiment and don’t remove until complete, as well as keep a snorkel positioned properly over your work space.

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Fill two large ice baths.

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Weigh out the specific amount of FeCl36H2O into a Erlenmeyer flask and add 15mL of distilled water. Then place this flask on the hot plate to mix the solution but not heat it.

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Mix methanol and acetylacetone and then add this solution into the iron chloride solution drop by drop.

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Then mix sodium acetate with water and add this dropwise to the solution still in the previous flask.

Experiment 4 Report

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Heat this solution for 10 minutes and then cool for 10 minutes after and finally place in an ice bath for 10 minutes.

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Use the vacuum filtration system to filter the product left in the flask and then weigh the mass of a watch glass with the filter paper.

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Record the mass and clean up lab station.

Recrystallization of Fe(acac)3

Reference lab manual pages 68-69 for more details. 

Once again set up your snorkel over the station.

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Prepare two hot water baths to 70 degrees Celsius.

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Transfer 0.3g of last weeks product into a small beaker and place the beaker into one of the hot water baths.

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Place 10mL of methanol into a small beaker and put this breaker into the hot water bath not on the hotplate!

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Add the hot methanol to the product until it dissolves then place this mixture into the hot water bath again to evaporate some of the methanol.

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When tiny crystals form remove the beaker from the bath and let it cool on the bench.

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While this is cooling turn the hot water bath into a ice water bath and chill the mixture in this.

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Finally filter the product in the vacuum filtration system and then weigh the solid product that is left as a result on a watch glass and record the mass.

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Take a small amount of the product left and find the melting point using the mel-temp and record the results.

Observations When acetylacetone solution was added to iron chloride solution 

Solution of iron chloride began as a transparent yellow with an orange tint. This liquid was viscous with no solid elements visible therefor a solution.

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As the acetylacetone solution was added drop by drop the solution become darker in the specific area that the drop landed in and then the stirring bar mixed until the whole solution became this colour.

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The new colour seemed to be a dark red/orange, almost the colour of a red wine. The surface of the liquid seemed slightly lighter and the solution still contained no solids and maintained the same viscosity. It was less transparent due to being a much darker colour.

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After a few drops of the acetylacetone solution was added and the colour initial changed to a dark red it stayed this colour when the rest of the solution was added. There was no colour change with more solution.

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Experiment 4 Report

When sodium acetate solution was added to previous solution 

As the sodium acetate was added drop by drop the surface of the liquid began to lighten up and become more of a vibrant orange, similar to the colour of a pumpkin.

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Small bubbles formed around the outside of the beaker most likely from the stir bar.

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As more solution was added all of the liquid in the beaker turned this orange colour. It is still slightly red and no longer transparent at all. This now looks like the colour of rust.

When the previous solution was heated 

When this solution was heated the bottom began to darken and the top surface remained slightly lighter and more orange.

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Over time the bottom was a dark red and almost black with lots of bubbles on the surface stuck to the sides of the beaker. It seemed that the solution was becoming thicker and less viscous.

When the solution cooled 

This is when the powder seemed to be created in our solution. This powder was then filtered out and was a fine powder that was red with a tint of orange.

When hot methanol was added to the powder to recrystalize 

This turned the liquid into a deep red with no solids in the solution.

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The solution was then heated which created tiny crystals to form on the bottom of the beaker. These were visible when the solution was swirled.

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Then the solution was cooled and the crystals began to grow slightly and the product became more solid. Brownian motion was present if the beaker was not moved you could see tiny crystals floating on the surface and moving slight due to inter molecular collisions.

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Once the solution was completely cooled larger crystal began to form and the product was all solid on the bottom of the beaker.

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The recrystalized product seemed to be less fine and a dark colour then the original crude, perhaps this is because it is more pure. 

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Experiment 4 Report

DATA SHEET

Crude Fe(acac)3 Mass of FeCl3∙6H2O /g Mass of watch glass /g Mass of watch glass and crude product /g (before recrystallization)

1.00 34.18 35.63

Recrystallized Fe(acac)3 Mass of watch glass /g Mass of watch glass and pure product /g (after recrystallization)

28.67 28.83

Experiment 4 Report

Calculations

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Experiment 4 Report

Questions From Part I 1. What is the limiting reagent? The limiting reagent is FeCl3 . 6H2O. See calculations above.

2. What is the percent yield of the crude product? The percent yield of the crude product is 76%.

3. Give three reasons why you did not get 100% yield. One reason could be because the crude product may not be pure and can have some impurities which would add weight to the actual crude yield and therefore change the ratio and the percent yield would be lower. Another reason could be that some of the crude product may be lost and not all transferred over. For example, this could happen by leaving some behind in a beaker or on a temperature probe etc. Finally, the crystals may have not all formed and been flushed out with the solvent. This would also change the weight of the experiment crude. From Part II 4. What is the percent yield of the pure product? The percent yield of the pure product is 50%.

5. Compare your crude vs. pure product yield. List three reasons why they may be different/same. The product yields are different by 26%. One reason for this may be because some of the impurities were taken out during the recrystallization stage. Some of the product may also be lost while the crystals are being washed and finally some of the product may be left dissolved in the solvent therefore not adding to the end mass.

6.

What can you say about the difference, if any, between the crude and the recrystallized product in your observed melting point data?

Crude melting point: start 186.0 degree Celsius- end 196.0 degree Celsius Recrystallized melting point: start 192.7 degree Celsius- end 197.8 degree Celsius The crude melting point is slightly lower than the recrystallized melting point. This is because impure solids melt at a lower temperature than pure ones. This is because when there is a foreign substance in a solid it will disrupt the forces that hold the solid together and therefore require a smaller amount of energy to melt the solid around the impurity.

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Experiment 4 Report

References 1.

First year laboratory manual

2.

Material Safety Data Sheet. (n.d.). Retrieved October 31, 2018, from https://fke.uitm.edu.my/SafetyFKE/MSDS_1/ACETYLACETONE.pdf.

3.

Transition metal complexes: Akins and Jones, Chemical Principles, pp. 680-700.

4.

Why do impure solids melt at lower temperatures: Melting points explained. (2018, August 07). Retrieved from https://kirsoplabs.co.uk/lab-aids/impure-solids-melt-lowertemperatures/.

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