ChemicalBook CAS DataBase List 1,2,3,4-TETRAMETHYL-1,3-CYCLOPENTADIENE

1,2,3,4-TETRAMETHYL-1,3-CYCLOPENTADIENE synthesis

5synthesis methods

Product Name:1,2,3,4-TETRAMETHYL-1,3-CYCLOPENTADIENE
CAS Number:4249-10-9
Molecular formula:C9H14
Molecular Weight:122.21

2-Cyclopenten-1-ol, 2,3,4,5-tetramethyl-

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4249-10-9
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Yield:4249-10-9 82%

Reaction Conditions:

with Dandong Pearl-H type cation exchange resin in diethyl ether at 25;Reagent/catalyst;

Steps:

1.2; 2-4 Example 1 2) Preparation of 1,2,3,4-tetramethyl-1,3-cyclopentadiene, the specific steps are as follows:

Weigh 30g of the 2,3,4,5-tetramethyl-2-cyclopentenol prepared in step 1), place it in a single-necked flask, add 100mL of ether solvent and 1.5g of Dandong Pearl-H type cation exchange resin catalyst, Stir the reaction at room temperature (25°C) and take the upper organic phase for gas chromatography detection every half an hour. When there is no characteristic peak showing 2,3,4,5-tetramethyl-2-cyclopentenol, it indicates the reaction carry out.After completion of the reaction, filtration was performed to obtain a filtrate and solid residue (catalyst); the solid residue was washed twice with ether (10 mL×2) and combined into the filtrate; the filtrate was evaporated to remove the solvent to obtain 1,2,3,4-tetramethyl Crude -1,3-cyclopentadiene crude product.Vacuum distillation (200Pa) of the above crude product was carried out, and fractions at 35 to 38°C were collected to obtain 21.44g of colorless oil, which was the target product (1,2,3,4-tetramethyl-1,3-cyclopentane) Diene).The filtered Dandong Pearl-H type cation exchange resin catalyst is placed in an oven, heated to 60°C and dried for 2 hours to remove the solvent, which can be used in the next batch of dehydration reaction.

References:

CN111253201,2020,A Location in patent:Paragraph 0037; 0046-0080

54458-61-6 Synthesis