Conversion of Carbonyl Compounds to Alkenes Using Wittig Reaction
SYNTHESIS OF TRANS-9-(2-PHENYLETHENYL) ANTHRACENE (A WITTIG REACTION)
Introduction:
The purpose of this experiment is to convert carbonyl compounds to alkenes using Wittig reaction. In this case we will be synthesizing Trans-9-(2-phenylethenyl) anthracene from benzyltriphenylphosphonium chloride and 9-anthraldehyde. We will also aim to obtaining a high percent yield and purity for the synthesis of Trans-9-(2-phenylethenyl) anthracene. The mechanism for this reaction goes thus:
Experimental:
Benzyltriphenylphosphonium chloride (0.201g) and 9-anthraldehyde (0.116g) were weighed and added to a short-neck round-bottomed flask (5ml). Dichloromethane (2ml) was measured using a measuring cylinder and added to the flask, and every solid material was washed down the bottom of the flask. The flask was then stirred using a magnetic stirrer at high speed whilst adding 50% aqueous sodium hydroxide (0.25ml) drop wise using a pipette.
After complete addition of the sodium hydroxide, the mixture was left to stir for a further 30 minutes after which we reduced the stirrer speed to a gentle spin and water (2ml) was added and then stirred for a few more minutes. The content was transferred to a separatory funnel (30ml), using water (5ml) and dichloromethane (5ml) to complete the transfer. The mixture was shaken and left to settle, the organic layer was removed to an Erlenmeyer flask and the aqueous layer was extracted once more with dichloromethane (5ml) and then combined with the previous organic extract. The combined organic layers were dried with anhydrous sodium sulfate, transferred through a Hirsch funnel into a filter flask (25m) attached to an aspirator. Filter paper was used to stop the drying agent from passing through the funnel, and the Erlenmeyer was rinsed with dichloromethane (1ml) and was poured over the drying agent in Hirsch funnel. After all the solvent went in the filter flask the aspirator was turned off, and the filter paper with
Introduction:
The purpose of this experiment is to convert carbonyl compounds to alkenes using Wittig reaction. In this case we will be synthesizing Trans-9-(2-phenylethenyl) anthracene from benzyltriphenylphosphonium chloride and 9-anthraldehyde. We will also aim to obtaining a high percent yield and purity for the synthesis of Trans-9-(2-phenylethenyl) anthracene. The mechanism for this reaction goes thus:
Experimental:
Benzyltriphenylphosphonium chloride (0.201g) and 9-anthraldehyde (0.116g) were weighed and added to a short-neck round-bottomed flask (5ml). Dichloromethane (2ml) was measured using a measuring cylinder and added to the flask, and every solid material was washed down the bottom of the flask. The flask was then stirred using a magnetic stirrer at high speed whilst adding 50% aqueous sodium hydroxide (0.25ml) drop wise using a pipette.
After complete addition of the sodium hydroxide, the mixture was left to stir for a further 30 minutes after which we reduced the stirrer speed to a gentle spin and water (2ml) was added and then stirred for a few more minutes. The content was transferred to a separatory funnel (30ml), using water (5ml) and dichloromethane (5ml) to complete the transfer. The mixture was shaken and left to settle, the organic layer was removed to an Erlenmeyer flask and the aqueous layer was extracted once more with dichloromethane (5ml) and then combined with the previous organic extract. The combined organic layers were dried with anhydrous sodium sulfate, transferred through a Hirsch funnel into a filter flask (25m) attached to an aspirator. Filter paper was used to stop the drying agent from passing through the funnel, and the Erlenmeyer was rinsed with dichloromethane (1ml) and was poured over the drying agent in Hirsch funnel. After all the solvent went in the filter flask the aspirator was turned off, and the filter paper with
References: Dictionary of organic compounds, 6th edition, Chapman and Hall, London, Volume 3(& Volume 6), 1996 Maria Lindsay and Sean P. Hickey, Organic chemistry lab 2 manual, department of Chemistry University of New Orleans