Method of preparing N-butyric acid by using poly-3-hydroxybutyrate

Abstract

The present invention relates to a method of preparing n-butyric acid by using poly-3-hydroxybutyrate. The method comprises following steps: placing poly-3-hydroxybutyrate in a closure means, passing hydrogen into the closure means to eliminate air after making an initial hydrogen pressure be 2 to 6 MPa, carrying out an agitation at 190 to 240 C. for reaction for 6 to 36 hours to obtain n-butyric acid. The preparation method provided by the present invention does not require a catalyst or a reaction solvent, and converts poly-3-hydroxybutyrate into n-butyric acid by a one-step reaction under a hydrogen atmosphere. The conversion rate of poly-3-hydroxybutyrate is 100%, the yield of n-butyric acid reaches up to 97%, the purity of n-butyric acid in all obtained liquid products reaches up to 98%, and no additional subsequent separation process is needed to the target product n-butyric acid.

Claims

1. A method of preparing n-butyric acid by using poly-3-hydroxybutyrate, characterized in that, the method comprises following steps: placing poly-3-hydroxybutyrate in a closure means, passing hydrogen into the closure means to eliminate air after making an initial hydrogen pressure be 2 to 6 MPa, carrying out an agitation at 190 to 240 C. for reaction for 6 to 36 hours to obtain n-butyric acid.

2. The method of preparing n-butyric acid by using poly-3-hydroxybutyrate according to claim 1, wherein a temperature for the reaction is 200 to 220 C.

3. The method of preparing n-butyric acid by using poly-3-hydroxybutyrate according to claim 1, wherein a time for the reaction is 12 to 24 hours.

4. The method of preparing n-butyric acid by using poly-3-hydroxybutyrate according to claim 1, wherein the initial hydrogen pressure is 3 to 4 MPa.

5. The method of preparing n-butyric acid by using poly-3-hydroxybutyrate according to claim 1, wherein the agitation is a mechanical agitation.

6. The method of preparing n-butyric acid by using poly-3-hydroxybutyrate according to claim 1, wherein a rate of the agitation is 500 to 1000 r/min.

7. The method of preparing n-butyric acid by using poly-3-hydroxybutyrate according to claim 1, wherein the closure means is an autoclave.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a gas chromatography-mass spectrometry spectrum of a product after poly-3-hydroxybutyrate is reacted in Embodiment 1.

DETAILED DESCRIPTION OF THE PREFERED EMBODIMENT

(2) The present invention is further described below in combination with embodiments. These embodiments are only intended to illustrate the present invention and are not intended to limit the scope of the present invention. Experimental methods in following embodiments, which do not specify specific conditions, are generally in accordance with conventional conditions in the art or in accordance with conditions recommended by the manufacturer. Raw materials, reagents, etc. used, unless otherwise specified, are raw materials and reagents available from commercial markets such as conventional market. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention are within the scope of protection of the present invention.

(3) Embodiment 1

(4) A method of preparing n-butyric acid by poly-3-hydroxybutyrate, which is as follows:

(5) 5 g of poly-3-hydroxybutyrate was placed in a 300 mL high temperature high pressure autoclave, hydrogen was passed into the autoclave to eliminate air from the autoclave until the hydrogen pressure was maintained at 4 MPa, and then the autoclave was sealed. A mechanical agitation started, the rate of the mechanical agitation was controlled at 1000 r/min, the autoclave was warmed up to 200 C. at a rate of 4 C./min, and the reaction was carried out at the temperature of 200 C. for 24 hours. After the reaction, the temperature was cooled to room temperature, poly-3-hydroxybutyrate was completely converted, and liquid products with n-butyric acid as a main component were obtained (see FIG. 1). By gas chromatography quantitative analysis, the yield of n-butyric acid was determined to be 97%, and the purity of n-butyric acid in the liquid product was 98%.

(6) Embodiment 2

(7) A method of preparing n-butyric acid by poly-3-hydroxybutyrate, which is as follows:

(8) 5 g of poly-3-hydroxybutyrate was placed in a 300 mL high temperature high pressure autoclave, hydrogen was passed into the autoclave to eliminate air from the autoclave until the hydrogen pressure was maintained at 5 MPa, and then the autoclave was sealed. A mechanical agitation started, the rate of the mechanical agitation was controlled at 800 r/min, the autoclave was warmed up to 210 C. at a rate of 4 C./min, and the reaction was carried out at the temperature of 210 C. for 18 hours. After the reaction, the temperature was cooled to room temperature, poly-3-hydroxybutyrate was completely converted, and liquid products with n-butyric acid as a main component were obtained. By gas chromatography quantitative analysis, the yield of n-butyric acid was determined to be 95%, and the purity of n-butyric acid in the liquid product was 97%.

(9) Embodiment 3

(10) A method of preparing n-butyric acid by poly-3-hydroxybutyrate, which is as follows:

(11) 5 g of poly-3-hydroxybutyrate was placed in a 300 mL high temperature high pressure autoclave, hydrogen was passed into the autoclave to eliminate air from the autoclave until the hydrogen pressure was maintained at 3 MPa, and then the autoclave was sealed. A mechanical agitation started, the rate of the mechanical agitation was controlled at 800 r/min, the autoclave was warmed up to 220 C. at a rate of 4 C./min, and the reaction was carried out at the temperature of 220 C. for 12 hours. After the reaction, the temperature was cooled to room temperature, and liquid products with n-butyric acid as a main component were obtained.

(12) Embodiment 4

(13) A method of preparing n-butyric acid by poly-3-hydroxybutyrate, which is as follows:

(14) 5 g of poly-3-hydroxybutyrate was placed in a 300 mL high temperature high pressure autoclave, hydrogen was passed into the autoclave to eliminate air from the autoclave until the hydrogen pressure was maintained at 3 MPa, and then the autoclave was sealed. A mechanical agitation started, the rate of the mechanical agitation was controlled at 500 r/min, the autoclave was warmed up to 190 C. at a rate of 4 C./min, and the reaction was carried out at the temperature of 190 C. for 36 hours. After the reaction, the temperature was cooled to room temperature, and liquid products with n-butyric acid as a main component were obtained.

(15) Embodiment 5

(16) A method of preparing n-butyric acid by poly-3-hydroxybutyrate, which is as follows:

(17) 5 g of poly-3-hydroxybutyrate was placed in a 300 mL high temperature high pressure autoclave, hydrogen was passed into the autoclave to eliminate air from the autoclave until the hydrogen pressure was maintained at 5 MPa, and then the autoclave was sealed. A mechanical agitation started, the rate of the mechanical agitation was controlled at 500 r/min, the autoclave was warmed up to 240 C. at a rate of 4 C./min, and the reaction was carried out at the temperature of 240 C. for 6 hours. After the reaction, the temperature was cooled to room temperature, and liquid products with n-butyric acid as a main component were obtained.

(18) Embodiment 6

(19) A method of preparing n-butyric acid by poly-3-hydroxybutyrate, which is as follows:

(20) 5 g of poly-3-hydroxybutyrate was placed in a 300 mL high temperature high pressure autoclave, hydrogen was passed into the autoclave to eliminate air from the autoclave until the hydrogen pressure was maintained at 2 MPa, and then the autoclave was sealed. A mechanical agitation started, the rate of the mechanical agitation was controlled at 800 r/min, the autoclave was warmed up to 240 C. at a rate of 4 C./min, and the reaction was carried out at the temperature of 240 C. for 12 hours. After the reaction, the temperature was cooled to room temperature, and liquid products with n-butyric acid as a main component were obtained.

(21) Those of ordinary skill in the art will appreciate that the embodiments herein are intended to assist the reader in understanding principles of the present invention, and it should be understood that the scope of protection of the present invention is not limited to such particular statements and embodiments. Those of ordinary skill in the art can make various other specific modifications and combinations without departing from the spirit of the present invention based on these technical teachings disclosed by the present invention, and these modifications and combinations are still within the scope of protection of the present invention.