Pages

Saturday, June 30, 2018

SYNTHESIS OF 2-METH YLBUT-2-ENE


STEP 1: Place 25.0 g (31 ml, 0.28 mol) of 2-methylbutan-2-ol and 10 ml of 85 per cent orthophosphoric acid in a 100-m1, round-bottomed flask and swirl to mix thoroughly. 


STEP 2: Fit the flask with a 20-cm fractionating column filled with glass helices, a Claisen still-head and a condenser leading to a 50-m1 receiving flask cooled in a beaker of iced water. 

STEP 3: Add a few pieces of porous por­celain and heat the reaction mixture gently with a Bunsen burner. 

STEP 4: Collect the alkene fraction which distils in the range 35-38 °C during a period of 30 minutes. 

STEP 5: Dry the distillate with 1-2 g of magnesium sulphate. 

STEP 6: Wash and dry the distillation apparatus, decant the dried distillate into a 50-m1 flask and redistil in the reassembled apparatus. 

STEP 7: Collect the fraction boiling at 37-38 °C; the yield is 12.5 g (64%). Record the infrared spectrum of the product using a fixed path-length cell (0.025 mm). 

STEP 8: The stretching bands of the terminal (1645 cm '} and non-terminal (1670 cm ') carbon–carbon double bonds can both be observed; bands at 890 and 805 cm (=C—H deformation) also establish the presence of both terminal and non-terminal olefinic systems. 

STEP 9: Analyse the product by g.l.c. on a Silicone oil column at 30 °C; 2- methylbut-1 -ene appears first, closely followed by 2-methylbut-2-ene; the areas under the peaks are in the ratio of 1:4.

No comments:

Post a Comment

We specialize in producing high value chemicals. Besides our regular products, we strive to develop new products based on customer’s requirements. Our R&D center plays crucial role in handling complex chemistries and developing newer technologies. We respect intellectual property rights and have confidentiality agreement with various multi national companies. We undertake contract manufacturing of fine chemicals and advance intermediates of API’s.