Question

Need help making a separation scheme for the synthesis of methylbutene based on the experiment procedure

Synthesis of Methylbutenes catalyzed Dehydration of 2 Meth H.SO buano detin vee distinct steps in most organic preparat the reaction itself solation of the final product final product purification ances, as in the dehydration of an alcohol, it is necessary to be the first two stesso oduct can be removed from the reaction mixture is formed. This was to drive the brium to toward alkene formation and to minimice the possibile c on or polymeration of bene nomenon of steam distillation is observed in this experiment water initially present in the and additional water formed as a result of the reaction is immiscible with the alkene product distillation experiment we learned that in a mixture of two meble liquids, the total vapor the sun of the partial pressures of each component. There is a different situation in the in of a mixture of two compounds that are not mutually soluble in this c a ch liquid exerts un vapor pressure independently of the other separate phases are present in the liquid, the mixture will have a constant boiling point that er than the boiling point of either component. In addition, the distillate will have a constant composition, which is determined by the ratio of the vapor pressures Objectives • Perform a dehydration reaction • Analyze the final product ratio by GC and NMR • Qualitatively analyze by IR • Understand the concept of steam distillation Safety Manards! PHOSPHORIC ACID (H,PO.) and SULFURIC ACID (H,SO) are corrosive and cause chemical burns and should be handled with great care. Wash affected area with water for 15 minutes WEAR GLOVES at all times. Some solvents are toxic and absorb easily on the skin. CHECK GLASSWARE for cracks and chips. Heating chipped or cracked glassware is a safety hazard.

Answer 1

Aim: to find the separation method of the isolation of the two products in the below given reaction.

Chemical Reaction:

nel но | settored H2SO4/H3PO4 Heat, . 2-methylbutan-2-ol Dehydration, Dean Stark 2-methylbut-1-ene 2-methylbut-2-ene

Procedure:

To a mixture 15 mL of cold 6 M H₂SO₄ and 2 ml of H₃PO₄ solution in a Dean-Stark flask was added 10 mL of 2- methyl-2-butanol and a boiling chip. the reaction mixture was heated to form the equal mixture of two alkenes products as 2-methyl-2- butene and 2-methyl-1-butene.

After the complete reaction the mixture of product condensed in the other part of Den-Stark receiver flask along with the  generated water from the dehydration reaction. It was transfered from Dean-Stark flask to the ice cooled conical flask.

The traces of acid was neutralized using 2M NaOH solution and the reaction mixture was extracted with the ethyl acetate.

Separation of two products:

The resulting mixture was subjected to the steam distillation, as the separation would occure based on the boiling points of both isomers. The 2-methyl-1-butene. is low boiling product having b. p. is  31 ⁰C will distillate first fraction and after slight increase in the temperature of reaction mixture the other product 2-methyl-2- butene having b. p.is 38.5⁰C would come as pure fraction. Both the products were analysed as separate injection to the Gas Chromatography

Analysis by Gas Chromatography (GC) and ¹ HNMR:

Both the products were analysed as separate injection to the Gas Chromatography and also the analysis of the fraction containing both alkene products.

The GC-MS analysis would confirm the two alkene products. Both alkene will have different elution time is also called as retention time. As 2-methyl-1- butene is low boiling liquid therefore it will elute first on GC and followed by the elution of high boiling 2-methyl-2-butene..

Two main peaks will appear on your gas chromatograph which record the retention times and areas for the two peaks. The areas under each peak are proportional to the relative amounts of each alkene product.

The ¹H NMR spectra of both the product can confirm the structure based on the NMR peak pattern. The characteristic triplet and quartet would be observed in the 2-methyl-1- butene, these triplet and quartet is absent in 2-methyl-2- butene