2,5-Dimethyl-2,4-hexadiene

clear colourless liquid

2,5-Dimethyl-2,4-hexadiene is an alkadiene.

The preparation method is prepared by dehydrating 2, 5-dimethyl-2, 5-hexanediol. There are two processes for its dehydration. First, the crystal water is dehydrated, and then intermolecular dehydration to obtain 2, 5-dimethyl-2, 4-hexadiene (diene for short). Put 2, 5-dimethyl-2, 5-hexanediol (generally containing 40% of crystal water, diol for short) in a reaction pot and heat it. When the liquid temperature reaches above 90～105℃, start dehydration. When it reaches 180℃ The crystal water can be basically removed, and the diol that removes the crystal water can be subjected to the next step of removing the intermolecular water to form 2, 5-dimethyl-2, 4-hexadiene. There are two methods for the intermolecular dehydration of 2, 5-dimethyl-2, 5-hexanediol to produce diene. There are two methods: gas phase dehydration and liquid phase dehydration. The more commonly used method is gas phase dehydration, which uses molten 2, 5-di Methyl-2, 5-hexanediol passes through a dehydration tower equipped with Al2O3 as the catalyst. The temperature of the dehydration tower is 180-300°C. The catalyst activity is large at the beginning of the reaction. The dehydration temperature can be lower. After dehydration of the diol, the generated The diene and water enter the receiver after cooling, and are separated by layers. The oil layer is dried and then distilled. The fraction collected at 130-132°C is 2, 5-dimethyl-2, 4-hexadiene. For example, using liquid phase dehydration, using orthophosphoric acid as a catalyst, when diol and orthophosphoric acid are reacted and dehydrated at 110°C, diene and water are produced, separated in layers, and the diene is obtained by fractional distillation of the oil layer. The disadvantage of this method is that the dilute phosphoric acid has high corrosivity and low dehydration conversion rate. Therefore, diene is prepared by gas phase dehydration of diol in industry. Sumitomo Chemical Co., Ltd. of Japan uses isobutylene and isobutyraldehyde to react with niobic acid as a catalyst in an autoclave at a temperature of 120 to 250°C for 4 hours to obtain 2, 5-dimethyl-2, 4-hexadiene, but different The conversion of butyraldehyde was 96.8%, while the selectivity was only 56.7%. Later further development showed that using 1:1 Fe2(SO4)3 and niobic acid as the catalyst and reacting at a pressure of 1 MPa, the conversion rate of isobutyraldehyde was 84.0%, while the selectivity could reach 79.4%. Enene has great development prospects.

A volatile alkyl compound present in tobacco smoke. It is used as a potential biomarker in breath for prediction of lung cancer.

Molecular Weight:110.20
XLogP3:3.6
Rotatable Bond Count:1
Exact Mass:110.109550447
Monoisotopic Mass:110.109550447
Heavy Atom Count:8
Complexity:92
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes