Conversion of a carboxylic acid to an acid chloride uses which reagent?

Master NCEA Level 3 Organic Chemistry Reaction Schemes. Prepare with multiple choice questions, complete with hints and detailed explanations. Ace your exam with our comprehensive tools!

Multiple Choice

Conversion of a carboxylic acid to an acid chloride uses which reagent?

Replacing the OH of a carboxylic acid with a chlorine atom to give an acid chloride requires a chlorinating activating agent that removes the OH as part of byproducts and delivers Cl to the carbonyl carbon. The standard reagents are thionyl chloride (SOCl2) or oxalyl chloride ((COCl)2), often used with a catalytic DMF, and sometimes phosphorus trichloride or phosphorus pentachloride. These reagents convert the carboxylic acid directly into the acid chloride by providing chloride to form the acyl chloride while generating gases (SO2/CO and HCl) that drive the reaction forward. The options listed are not reagents that accomplish this transformation. Alcohol, amide, and ester are functional groups, not reagents. An acid chloride reagent would not convert a carboxylic acid into another acid chloride; reacting with an acid chloride tends to form a mixed anhydride rather than the target product. So, the correct approach is to use a chlorinating activating reagent like thionyl chloride or oxalyl chloride, not an acid chloride.

Replacing the OH of a carboxylic acid with a chlorine atom to give an acid chloride requires a chlorinating activating agent that removes the OH as part of byproducts and delivers Cl to the carbonyl carbon. The standard reagents are thionyl chloride (SOCl2) or oxalyl chloride ((COCl)2), often used with a catalytic DMF, and sometimes phosphorus trichloride or phosphorus pentachloride. These reagents convert the carboxylic acid directly into the acid chloride by providing chloride to form the acyl chloride while generating gases (SO2/CO and HCl) that drive the reaction forward.

The options listed are not reagents that accomplish this transformation. Alcohol, amide, and ester are functional groups, not reagents. An acid chloride reagent would not convert a carboxylic acid into another acid chloride; reacting with an acid chloride tends to form a mixed anhydride rather than the target product. So, the correct approach is to use a chlorinating activating reagent like thionyl chloride or oxalyl chloride, not an acid chloride.

More practice questions