52nd International Chemistry Olympiad, Istanbul, TURKEY
Preparatory problems: PRACTICAL
Problem P4. 1-Bromobutane Nucleophilic substitution reactions are the most fundamental reactions among the organic functional group transformations. In these reactions, an electronegative atom or electronwithdrawing group is replaced by another atom or group. Replacement of the hydroxyl group is subject to special interest since it has a vital role in carbohydrate chemistry. For instance, sucrose is commonly used in our everyday life since many carbohydrates taste sweet. When we consume sucrose, excess calories are stored as fat in our bodies. To avoid the storage of fat because of excessive sucrose consumption, sucrose can be converted to synthetic sweetener, sucralose, through substitution reactions. On the other hand, sucralose is known diet friendly and it is much sweeter than sucrose.
Considering the impact of substitution reactions in our everyday life, in this task, you are asked to synthesize 1-bromobutane starting from 1-butanol by an SN2 reaction. Among several routes, an aqueous solution of sodium bromide and excess sulfuric acid method is preferred.
Chemicals Substance Name C4H9OH 1-Butanol
State Liquid
H2SO4
Sulfuric acid
Aqueous solution
NaBr
Sodium bromide
Solid
GHS Hazard Statement H226, H302, H315, H318, H335, H336, P210, P280, P301 + P312 + P330, P302 + P352, P305 + P351 + P338 + P310 H290, H314, P280, P301 + P330 + P331, P303 + P361 + P353, P305 + P351 + P338 + P310 Not hazardous
190
