Valeric Acid CAS 109-52-4

In order to solve the problems in the prior art, an embodiment of the present invention provides a method for producing Valeric Acid. Described technical scheme is as follows:

On the one hand, a kind of method of producing Valeric Acid is provided, is characterized in that, comprises the following steps:

(1) Preparation of Grignard reagent: add a part of 1-chlorobutane to the mixture of metal magnesium and solvent, after heating to initiate the reaction, add the remaining 1-chlorobutane dropwise within 3~10min, and keep the reaction system at reflux state, after the 1-chlorobutane has been added dropwise, the reaction system is continued to reflux until the reaction is completed, wherein the mol ratio of 1-chlorobutane to magnesium is (1~20):9, the 1-chlorobutane added in the first part Alkanes are (22~24)% of the total amount of 1-chlorobutane, the solvent is tetrahydrofuran or ether, and the volume ratio of solvent to 1-chlorobutane is (4~5): 1;

(2) Add the reaction mixture obtained in (1) dropwise to a reaction vessel equipped with dry ice within 10~30min. After the dropwise addition, naturally rise to room temperature, then add MHSO4, stir, and suction filter after the reaction is complete, and the filtrate is acidified Rear purification obtains n-valeric acid, wherein the magnesium added in (1): the dry ice added in (2): MHS04=9:27:7, M is K or Na.

Preferably, in the step (1), the 1-chlorobutane added in the first part is 23% of the total amount of 1-chlorobutane.

Preferably, in the step (1), the molar ratio of 1-chlorobutane to magnesium is 1: (1.4~1.6), more preferably 2: 3.

Preferably, the step (1) is carried out under the protection of an inert gas. Because the Grignard reagent will be consumed by air and water, such as nitrogen or argon, which will affect the reaction effect.

Preferably, in the step (2), the purification refers to acidifying the filtrate to a pH value of (3~4), then extracting the acidified filtrate with ether, merging and drying the organic phases, and finally removing the ether to obtain The Valeric Acid. Usually, the reagent added during acidification is 2mol/L dilute hydrochloric acid or 1mol/L dilute sulfuric acid.

More preferably, said M is K.

More preferably, the solvent is tetrahydrofuran.

In the described step (1), a part of 1-chlorobutane added earlier can be used as an initiator to initiate the reaction. After the reaction is initiated, it will exotherm, so that the reaction system boils, and the solvent begins to reflux. As a known technology, proper heating is required during the initiating reaction to promote the initiation of the initiating reaction. Then the remaining 1-chlorobutane can be added dropwise in 3~10min (preferably 4~6min, such as 5 minutes). If the reaction is violent, the rate of addition should be properly controlled to maintain the reaction system in a reflux state. Obviously, this step reaction temperature is relevant with the boiling point of concrete solvent, when solvent adopts tetrahydrofuran, the reaction temperature of step (1) is controlled at 25 DEG C～reflux temperature, promptly before dripping remaining 1-chlorobutane, reaction temperature is in 25°C～reflux temperature, after the remaining 1-chlorobutane is added dropwise, the reaction temperature is basically stable at the reflux temperature. After dropping the remaining 1-chlorobutane, the required reaction time can be determined experimentally by those skilled in the art, preferably 1 ~ 3h, such as 2h.

In the step (2), the reaction mixture obtained by (1) is added dropwise in a reaction vessel equipped with dry ice within 10 ~ 30min, for example, the time for adding is 30 minutes.

As common knowledge in the field, the preparation of Grignard reagent needs to be carried out under anhydrous conditions, so the reaction raw materials must be anhydrous, and water removal treatment can be used in advance. For example, 1-chlorobutane is put into the reaction after freezing and deicing.