The first step is to synthesize hydrated terpene diol: mix 272g of industrial grade turpentine or one of α-pinene or β-pinene with acid water with an acid mass fraction of 20-75% and put it into the reactor, Wherein the acid-water mixture is made of one or two or more of sulfuric acid, phosphoric acid, p-toluenesulfonic acid, and chloroacetic acid mixed with water to form a catalyst, and polyvinyl alcohol, organic One or more of the amine salts are used as emulsifiers, and the hydration reaction is carried out under stirring conditions of 100 to 1000 rpm (preferably 400 to 800 rpm) to generate crystalline hydrated terpene glycol, and ultrasonic waves are used in the initial 2 to 4 hours of the reaction. Assisted emulsification. The mass of water is 1-3 times, preferably 1-2 times, the mass of turpentine; the mass of the catalyst is 20-75%, preferably 25-50% of the mass of the turpentine; the mass of the emulsifier is 0.001-0.2% of the mass of the turpentine , preferably 0.01-0.1%; the reaction temperature is 20-75°C, preferably 20-60°C; the reaction time is 12-36h, preferably 18-24h. Turpentine is one or more mixtures of gum turpentine, sulfate turpentine, or wood turpentine and dry distillation turpentine. Industrial grade α-pinene or β-pinene and α-pinene or β-pinene derived from other natural essential oils (such as eucalyptus oil, camphor oil, etc.) are used as reaction raw materials instead of turpentine.
In the second step, the stirring is stopped after the hydration reaction is completed, and ultrasonic waves are used to vibrate and stir for a certain period of time, and then the acid-water mixture containing a small amount of hydrated terpene glycol is released from the bottom of the reactor after sedimentation and stratification, and the acid-water mixture after further clarification is formulated After reaching an appropriate proportion, all of them are recovered for the next reaction.
In the third step, the crystalline product left in the reactor is neutralized and washed once with an aqueous NaOH solution with a mass fraction of 3 to 5%. During the washing process, the acid catalyst remaining between the crystals is fully obtained by ultrasonic strengthening. After the recovery of the alkaline washing solution, an appropriate amount of NaOH can be added to prepare an aqueous solution with a mass fraction of 5% for the next batch of neutralization and washing.
In the fourth step, the crystalline product after alkali neutralization and washing is washed with water under the action of ultrasonic strengthening until the washing liquid is neutral and weakly alkaline. The washing liquid is released, and the washing liquid obtained by each recovery is used for the washing of the next batch of reaction products, and the washing water that cannot be reused is put into the neutralization tank for clarification and then recycled.
The 5th step, dehydration of terpene glycol to synthesize terpineol: the hydrated terpene glycol crystalline product obtained through neutralization and water washing and the unseparated red oil contained therein are transferred into the dehydration reactor under the action of adding water and stirring, with One or a mixture of two or more of the commonly used inorganic or organic acids such as sulfuric acid, phosphoric acid, p-toluenesulfonic acid and chloroacetic acid are used as catalysts, and the hydration terpene glycol is accelerated in the aqueous medium with ultrasonic assistance within 1 hour after the material is added. Dispersing and dissolving in the terpene glycol, the dehydration reaction of terpene glycol is carried out to generate the crude product of terpineol commonly known as butter. During the dehydration reaction, the mass of water is 1 to 2 times, preferably 1 to 1.5 times, the mass of the hydrated terpene diol and the red oil; the mass of the catalyst is 0.1 to 2.5% of the mass of the hydrated terpene diol and the red oil, preferably 0.1 ~1.0%; the reaction temperature is 60-120° C., preferably 80-110° C.; the reaction time is 2-12 h, preferably 3-6 h.
The sixth step, separating and refining terpineol: after the hydration reaction and the dehydration reaction are completed, stand to separate out the lower acid liquid layer. The obtained crude terpineol product of the upper layer oil, namely butter, is neutralized with an aqueous sodium hydroxide solution with a mass fraction of 2-10% and washed with water until the washing solution is neutral and slightly alkaline (pH=7-9), The crude product is obtained by standing for stratification, and then through vacuum distillation and continuous rectification to obtain a terpineol product that meets the standard.