Organic 2 Review Problem 194

Organic 2 Review Problem 194 - 178 P RACTICAL ORGANIC...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
178 PRACTICAL ORGANIC CHEMISTRY off the carbon tetrachloride (b.p. 77°) at atmospheric pressure. Distil the residue at water-pump pressure. The fraction coming over below about 58°/i4 m.m. is unchanged ethyl crotonate. Collect the fraction boiling at 98-99°/14 m.m. This is pure ethyl y-bromocrotonate, a colourless, mobile liquid having a strong pleasant odour. Yield, 25 g. Sulphonation. A further difference between aliphatic and aromatic hydrocarbons is that only the latter are capable of direct suiphonation. Thus benzene when heated with concentrated sulphuric acid gives benzenesulphonic acid, a reaction which proceeds more readily, however, if chlorosulphonic acid is used instead of sul- phuric acid: an excess of chlorosulphonic acid however may convert the sul- phonic acid into the sulphonyl chloride (cf. p. 181). C 6 H 5 H + HOSO 3 H -> C 6 H 5 SO 3 H + H 2 O C 6 H 5 H + ClSO 3 H -> C 6 H 5 SO 3 H + HCl Aromatic sulphonic acids are frequently difficult to obtain pure, since they
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/19/2011 for the course CHM 2211 taught by Professor Castalleano during the Fall '06 term at University of Florida.

Ask a homework question - tutors are online