Preparation Of Triphenylmethanol
Preparation Of Triphenylmethanol
Objectives
1. To study the preparation of triphenylmethanol using through Gridnard reaction
2. To study the operations of anhydrous reaction, water vapor distillation.
Principles
Alcohol is widely used in organic chemistry, not only as solute but also as intermediate to synthesize halide, alkene, ether, aldehyde and ketone etc. In laboratory, an important method of synthesizing alcohol is though the addition reaction of Gridnard reagent and carbonyl compound, whereas aldehyde is the most reactive and then to ketone or ester. Primary alcohol is produced through reaction between Gridnard reagent and formaldehyde or ethylene oxide or alcohol halide; secondary alcohol is produced using Gridnard reagent and aldehyde or carboxylate; while tertiary alcohol is produced using Gridnard reagent and ketone, ester, chloride or unsaturated ester etc. Gridnard reagent is prepared by reaction between Mg and halogenated aliphatic or aromatic halogenated, under common circumstances 1mol Mg is needed for 1mol of halogenated. Considered the side reactions, Mg should be in excess for about 10%-15%. The reactivity decrease from iodine to chlorine, but iodine also causes most side reactions, thus giving a lower product rate than Br or Cl. Also noted that chloride usually reacts very slowly with Mg.
Gridnard reagent is very reactive, not only reacts with H2O or organic compound with acidic hydrogen atom (ROH, RSH, RCO2H, RNH2, RCONH2, RSO3H etc), but also with O2 etc. Thus water and oxygen must be completely eliminated during the reaction process where Gridnard reagent participated, as well as the organic compound with acidic hydrogen. There reaction formula are as followed:
RMgX+H2O R H+XMgOH, RMgX+ [O] ROMgX R-OH+XMgOH
Befor reaction N2 is pumped in to eliminate O2. The solute we used is ether, which is volatile and releasing vapor to eliminate O2. Mg should be in small pieces or powders, predried for 30min in 60-80°C followed by
Objectives
1. To study the preparation of triphenylmethanol using through Gridnard reaction
2. To study the operations of anhydrous reaction, water vapor distillation.
Principles
Alcohol is widely used in organic chemistry, not only as solute but also as intermediate to synthesize halide, alkene, ether, aldehyde and ketone etc. In laboratory, an important method of synthesizing alcohol is though the addition reaction of Gridnard reagent and carbonyl compound, whereas aldehyde is the most reactive and then to ketone or ester. Primary alcohol is produced through reaction between Gridnard reagent and formaldehyde or ethylene oxide or alcohol halide; secondary alcohol is produced using Gridnard reagent and aldehyde or carboxylate; while tertiary alcohol is produced using Gridnard reagent and ketone, ester, chloride or unsaturated ester etc. Gridnard reagent is prepared by reaction between Mg and halogenated aliphatic or aromatic halogenated, under common circumstances 1mol Mg is needed for 1mol of halogenated. Considered the side reactions, Mg should be in excess for about 10%-15%. The reactivity decrease from iodine to chlorine, but iodine also causes most side reactions, thus giving a lower product rate than Br or Cl. Also noted that chloride usually reacts very slowly with Mg.
Gridnard reagent is very reactive, not only reacts with H2O or organic compound with acidic hydrogen atom (ROH, RSH, RCO2H, RNH2, RCONH2, RSO3H etc), but also with O2 etc. Thus water and oxygen must be completely eliminated during the reaction process where Gridnard reagent participated, as well as the organic compound with acidic hydrogen. There reaction formula are as followed:
RMgX+H2O R H+XMgOH, RMgX+ [O] ROMgX R-OH+XMgOH
Befor reaction N2 is pumped in to eliminate O2. The solute we used is ether, which is volatile and releasing vapor to eliminate O2. Mg should be in small pieces or powders, predried for 30min in 60-80°C followed by