Time management is very much important in IIT JAM. The eduncle test series for IIT JAM Mathematical Statistics helped me a lot in this portion. I am very thankful to the test series I bought from eduncle.
Nilanjan Bhowmick AIR 3, CSIR NET (Earth Science)
Shweta Thakur posted an Question
February 18, 2021 • 16:45 pm
![]()
30 points
30 points
- IIT JAM
- Chemistry (CY)
Please explain problem 27 3 h h :qch a hemiketal h b b :och, ch-c-ch, ch-c-ch qch :0ch h
mechanism for acid-catalyzed acetal or ketal formation HT OH OH CH,QH CHC=CH3 CH-C=CH :0CH C CH CH3 H H :QCH a hemiketal H B B :oCH, CH-C-CH, CH-C-CH QCH :0CH H, CH CH 0CHs :QCH C.ocH ketal H,0 Although the tetrahedral carbon of an acetal or ketal is bonded to two oxygen atoms, causing us to predict that the acetal or ketal is not stable, the acetal or ketal can be iso lated if the water eliminated from the hemiacetal (or hemiketal) is removed from the reaction mixture. This is because, if water is not available, the only compound the ac- etal or ketal can form is an O-methylated carbonyl compound, which is less stable than the acetal or ketal. The acetal or ketal can be transformed back to the aldehyde or ketone in an acidic aqueous solution. OCHCH3 CH,CH,OH CH,CH-C-CH OCH:CHs CHCH CH Section 18.7 Reactions of Aldehydes and Ketones with Oxygen Nucleophiles 757 ROBLEM 26 Show the mechanism for the acid-catalyzed hydrolysis of an acetal. ROBLEM 27 xplain mechanistically why an acetal or ketal can be isolated but most hydrates can't be olated.
1 Answer(s)
Answer Now
- 0 Likes
- 1 Comments
- 0 Shares
Do You Want Better RANK in Your Exam?
Start Your Preparations with Eduncle’s FREE Study Material
- Updated Syllabus, Paper Pattern & Full Exam Details
- Sample Theory of Most Important Topic
- Model Test Paper with Detailed Solutions
- Last 5 Years Question Papers & Answers
Sign Up to Download FREE Study Material Worth Rs. 500/-
Pinky chaudhary Chaudhary![best-answer]()
In the case of a hydrate, a neutral species can be formed by loss of a proton. In the case of a hydrate, the tetrahedral intermediate can be oxidized by oxygen In the case of an acetal, the only way to form a neutral species is to reform the acetal. m The molecules of acetal are stabilized by formation of complexes. when a tetrahedral intermediate collapses the intermediate that is formed is very unstable because of the positive charge on the sp oxygen atom. When a tetrahedral intermediate collapses, the intermediate that is formed is very unstable because of the negative charge on the sp carbon atom