Writing an Experimental
1. An experimental is a concise description of how to run an experiment and the expected results
a. Should be sufficient for another person to duplicate the experiment
i. Includes procedure, reagents, solvents, reaction conditions, reaction time, etc
b. Should be short and to the point
c. Uses correct grammar and spelling
2. Structure of the experimental
a. IUPAC Name of the chemical product in bold, followed by a period.
b. Description of the reagents and solvents used and how they were introduced to the reaction
i. Describe reagents and solvents in the order in which they are added
ii. Masses, volumes, and mmols (or molarity for solvents) are in parenthesis after the name of the chemical
1. Solids reagents should have mass and mmols.
2. Liquid reagents should have volume and mmol.
iii. Include temperature and any other special reaction conditions (Ex. under argon or nitrogen)
c. Notation of any special equipment used
i. It is assumed the reader has enough chemical background to understand how to set up typical reactions
d. Description of reaction conditions and any noteworthy observations
i. Reaction conditions include temperature, reaction time, atmospheric conditions, etc.
ii. Color changes, gas evolution, phase changes, and temperature changes should all be noted.
1. Use simple and consistent descriptions of colors and observations
iii. Any out of the ordinary behaviors of the reactions that may cause difficulty running the experiment
e. Description of the work-up and isolation
i. Specifics of standard work up conditions are usually not mentioned
e. Report on the final mass recovered, percent yield, and physical description of the product
i. Physical description includes color and phase (solid, oil, gel, etc)
ii. Mass and percent yield in parentheses after the description of the product
iii. All other physical data is included in supplemental information
f. Use of proper abbreviations, notations, and formatting for numbers.
3. A sample experimental
N-Methylbenzenesulfonamide. To a solution of methylamine (0.310 g, 10.0 mmol) in methylene chloride (100 mL, 0.1M) at 0 ºC, benzenesulfonyl chloride (1.75 g, 10.0 mmol) was added dropwise followed by triethylamine (2.13 mL, 15.3 mmol) and a catalytic amount of dimethylaminopyridine. Upon the addition of the base the solution turned bright yellow which faded over time. The reaction was allowed to stir at room temperature for 4 hrs monitored by TLC. The reaction was poured into an excess of HCl (10%), extracted three times with DCM, and washed with brine. The solvent was evaporated under reduced pressure to give the product as a yellowish oil (1.33 g, 78% yield).
1. An experimental is a concise description of how to run an experiment and the expected results
a. Should be sufficient for another person to duplicate the experiment
i. Includes procedure, reagents, solvents, reaction conditions, reaction time, etc
b. Should be short and to the point
c. Uses correct grammar and spelling
2. Structure of the experimental
a. IUPAC Name of the chemical product in bold, followed by a period.
b. Description of the reagents and solvents used and how they were introduced to the reaction
i. Describe reagents and solvents in the order in which they are added
ii. Masses, volumes, and mmols (or molarity for solvents) are in parenthesis after the name of the chemical
1. Solids reagents should have mass and mmols.
2. Liquid reagents should have volume and mmol.
iii. Include temperature and any other special reaction conditions (Ex. under argon or nitrogen)
c. Notation of any special equipment used
i. It is assumed the reader has enough chemical background to understand how to set up typical reactions
d. Description of reaction conditions and any noteworthy observations
i. Reaction conditions include temperature, reaction time, atmospheric conditions, etc.
ii. Color changes, gas evolution, phase changes, and temperature changes should all be noted.
1. Use simple and consistent descriptions of colors and observations
iii. Any out of the ordinary behaviors of the reactions that may cause difficulty running the experiment
e. Description of the work-up and isolation
i. Specifics of standard work up conditions are usually not mentioned
e. Report on the final mass recovered, percent yield, and physical description of the product
i. Physical description includes color and phase (solid, oil, gel, etc)
ii. Mass and percent yield in parentheses after the description of the product
iii. All other physical data is included in supplemental information
f. Use of proper abbreviations, notations, and formatting for numbers.
3. A sample experimental
N-Methylbenzenesulfonamide. To a solution of methylamine (0.310 g, 10.0 mmol) in methylene chloride (100 mL, 0.1M) at 0 ºC, benzenesulfonyl chloride (1.75 g, 10.0 mmol) was added dropwise followed by triethylamine (2.13 mL, 15.3 mmol) and a catalytic amount of dimethylaminopyridine. Upon the addition of the base the solution turned bright yellow which faded over time. The reaction was allowed to stir at room temperature for 4 hrs monitored by TLC. The reaction was poured into an excess of HCl (10%), extracted three times with DCM, and washed with brine. The solvent was evaporated under reduced pressure to give the product as a yellowish oil (1.33 g, 78% yield).