SC CHEM 333 - Synthesis of Phthalic acid Pre-Lab (8 pages)

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Synthesis of Phthalic acid Pre-Lab



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Organic Chemistry 333L section 03M Laboratory Pre Lab Synthesis of Phthalic acid Synthesized By Cameron Kahn Instructor TA James Collie 13 January 2019 1 Page Object In this experiment a person will be able to purify phthalic acid by means of recrystallization and recover a pure stable compound with a minimum loss of product They will also be able to find the melting point mass of the product and calculate the percent recovered Theory The most important method for purification of a solid organic compound is crystallization Most commercial samples are only 95 96 pure and need to be purified using recrystallization It is a rapid and convenient method CITATION Geo12 l 1033 The recrystallization process purifies alum aspirin and copper sulfate One of the most important parts of the recrystallization process is choosing the right solvent for the job The solvent should allow impure organic solid to dissolve completely when heated When the solution cooled to room temperature or below the solid should recrystallize from solution in a pure form The solid then should be isolated in a pure form while the impurities in the solid fail to dissolve at the elevated temperature or remain dissolved when the solutions is cooled Separating crystals from the solvent done by means of gravity filtration Gravity Filtration is a technique used to separate a solid from a liquid The solid separated from the liquid phase by passing the mixture over a filtering media The mixture forced through the filter by either gravity or reduced pressure on one side of the filter by creating a vacuum It is possible to separate a solid from a liquid by either technique however there are advantages to each technique CITATION Boa13 l 1033 Procedure Start by measure 100mg of impure phthalic acid and placing it in a small test tube Now add 11 5 mL of room temperature water and a boiling stone Bring the solution to a boil by using the heating mantle with a Variac setting of 50 Be sure to place the test tube in a holder pointing away from people while heating the solution When the solution begins to boil wait to see if all solids dissolve If any solids remain add a few drops of water Be careful not to add to much water as to maintain a saturated solution Check to make sure if there any insoluble impurities in your solution as they will need to be removed by means of a hot gravity filtration With the solids dissolved and the insoluble removed allow the hot solution of phthalic acid to stand at room temperature for 5 10 minutes Now to complete the recrystallization by cooling the phthalic acid solutions test tube in an ice bath Crystals should start to form If crystals are not forming scratch the inside of the test tube with a glass stirring rod to start the process Once crystals start to form collect the product by means of the Buchner suctions funnel process When the product collect in the Buchner funnel wash the product free of a soluble impurities with a few drops of ice cold water Do not use hot water or room temperature water to wash the product because you will lose some of your product Leave your product in the Buchner funnel to drain for a few minutes as to remove as 2 Page much of the solvent as possible Spread out the solid product on filter paper and let dry Next record the mass of the dried product and calculate percent recovered melting point and percent difference and record your finding in your lab book Apparatus Equipment Needed I II III IV V VI Small Test Tube Figure 1 Suctions Filtration Apparatus Figure 2 Test Tube Holder Figure 5 Test Tube Rack Figure 1 Scoopula Figure 4 Heating Mantle Figure 3 Figure 2 Buchner Funnel Apparatus Figure 1 Test tube rack Figure 3 Heating Mantle Figure 5 Holder Figure 4 Scoopula Attach the three finger clamp to a ring stand Next you will need to secure the neck of the filter flask with the clamp Secure the filter flask adapter on the open end of the Buchner funnel containing the pre weighed filter paper Connect the tube to the Figure 1 test tube and rack filter flask and the aspiration Set the water to a high flow rate to create suction Check for suction by pushing down lightly on the top of the Buchner funnel with the open palm of your hand You should feel a small pull on the palm of your hand if not check all connections Always dismantle by disconnecting the vacuum tube first then removing the filter and adapter flask Rinse the flask with acetone and drain in to liquid organic waste container then rinse with water and dry Rinse test tube and Buchner funnel with acetone and drain into liquid organic waste container then rinse with water and dry Discard the soiled filter paper in the solid organic waste container and set apparatus to dry CITATION Geo12 l 1033 3 Page Chemical Table Name Structure Phthalic acid Atomic Weight Melting Point Boiling Point Density 166 14 g mol 191 230 C 207 C 1 59 g cm C6H4 CO2H 2 Disposal Use the solid organic waste container to dispose of all phthalic acid and filter paper Make sure to flush filtrate down the drain with tap water Soiled gloves and paper towels need to be disposed of in their proper containers Any broken glass needs placed in the broken glass container Consult the TA if unsure about any disposal procedure 4 Page Works Cited Ali George Handy and Salman Chemistry 333 334 Laboratory Manual Columbia South Carolina QDE Press 2012 System Board of Regents of the University of Wisconsin Chem Pages Laboratory Resources 26 1 2013 26 1 2013 http chem wisc edu deptfiles genchem lab labdocs modules gravfilt gravfiltdesc htm 5 Page Organic Chemistry 333L section 001 Laboratory Post Lab Synthesis of Phthalic acid Synthesized by Christopher N Rufty 13 January 2019 6 Page Synthesized for Organic Lab Dr Handy and Fiona Oxshu Results Phthalic acid is a white crystal While doing the experiment there were no visible signs of impurities The recrystallized crystals looked long clear shards like white stained glass A watch glass used to collect the phthalic acid with a dry mass of 37 256g The initial mass of the phthalic acid used at the start of the experiment was 0 104g The pure product collected and the mass of the watch glass 37 356g A difference of 0 100g pure phthalic acid refined A melting point of 215 observed The percent recovered was 96 15 pure phthalic acid and the difference in temperature is 6 52 percent The mass of the recrystallized phthalic acid was well in the accepted range Percent Recovery Amount Pure Solid 100Percent Difference T


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