Gamma Valerolactone CAS 108-29-2

For a long time, the synthesis of Gamma Valerolactone at home and abroad has adopted the condensation reaction of heptanal and malonic acid to generate noneenoic acid, which is then prepared by heating cyclization with HY molecular sieve or sulfuric acid as the lactating agent. This method is synthesized in two steps, the yield of next nonolactone is only about 52%, there are many side reactions, the product quality is unstable, and the energy consumption is large. In recent years, solid strong bases can make such reactions carry out highly active catalytic reactions under mild conditions, which not only saves energy, but also reduces environmental pollution, which is in line with the research direction of green chemistry. of attention.

(1) A new process for the one-step catalytic synthesis of gamma nonolactone using a solid strong base supported by organic barium phosphate as a condensation catalyst

In a 50mL dry three-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a dropping funnel, add 1.4-dioxane, malonic acid and a solid strong base (barium polyvinylpolyaminoethylphosphonate- KOH-K), stir slowly to dissolve malonic acid completely, and add freshly distilled heptanal dropwise within 30 min at 40-50 °C. Start heating to make the reaction temperature between 75-85 ℃, and react for about 1 h until no more carbon dioxide is released. Then it was raised to a constant temperature for reaction, and the reaction was continued for a period of time. After the completion of the reaction, suction filtration while hot to recover the catalyst, the filtrate is naturally cooled to room temperature, and 100 ml of 10% KOH solution is added to the reactant under stirring. After separating the organic layer, the aqueous phase was extracted twice with 50 mL of 1.4-dioxane, the 1.4-dioxane extract was combined with the organic layer, washed with water until neutral, and dried with anhydrous sodium sulfate. Atmospheric distillation recovered 1.4-dioxane, then vacuum distillation, collected Gamma Valerolactone at 123-128℃(800pa).

2) There are four main methods for synthesizing alkyl γ-lactones from α-olefins:

1. α-heptene reacts with sodium hypochlorite in the presence of chlorourea to obtain amyl chloroethanol, which is then reacted with calcium hydroxide to obtain amyl oxirane, which is reacted with sodium malonate and then hydrolyzed , heating to generate gamma non-lactone.

2. Using high-valent acetate such as cerium and vanadium or manganese acetate as oxidant, it is prepared by the reaction of α-heptene and acetic acid

3. Using bromoacetic acid and α-olefin as raw materials, using benzoyl peroxide as catalyst, through free radical reaction, it is prepared under mild conditions. This method has a higher yield.

4. Slowly add octene to the acetic acid heterogeneous mixture of potassium peroxodisulfate, fatty acid potassium and basic ferric acetate at 120-140 ° C, to obtain lactone with a yield of 65% after the reaction, and the olefin conversion rate is 49 % .

Summarize above 4 kinds of routes in the 1st method reaction process is complicated, the raw material consumption is more, and some are not easy to obtain; The shortcoming of the 3rd method is that bromoacetic acid is difficult to prepare and the price is higher; The shortcoming of the 4th method is the potassium peroxodisulfate value high and complex. Therefore, the second route is adopted. The advantages of this method are that the raw materials are cheap and easy to obtain, the reaction steps are few, and the industrialization is possible.