CN1258585C - A new process of directly using short-chain fatty acid esters as solvents to extract oil from oil-containing raw materials - Google Patents

Abstract

The invention discloses a new process of directly using short-chain fatty acid ester as a solvent to extract oil from oil-containing raw materials, which belongs to the technical field of oil extraction. The crushed oil-containing raw material is mixed with short-chain fatty acid ester RCOOR' according to the volume ratio, and after shaking for a certain period of time, vacuum filtration is performed several times to extract the ester mixture mainly including short-chain fatty acid ester and oil. These short-chain fatty acid esters can be directly used to replace conventional extraction solvents such as n-hexane to extract oil from oily raw materials such as soybeans and rapeseed, and the extracted ester mixture can be further used for the preparation of biodiesel. The invention is particularly suitable for the new process of directly using the short-chain fatty acid ester instead of the conventional extraction solvent to extract oil from the oil-containing raw material when the short-chain fatty acid ester is used as a reactive acyl acceptor to prepare biodiesel. The invention has an excellent industrial application prospect no matter in view of the production process or the production cost.

Description

A new process of directly using short-chain fatty acid esters as solvents to extract oil from oil-containing raw materials

technical field

The invention belongs to the technical field of oil extraction. In particular, it relates to a method of directly using short-chain fatty acid ester RCOOR' (R, R' carbon number range of 1-4, such as methyl acetate, ethyl acetate, etc.) as an acyl acceptor to prepare biodiesel A new process for extracting oil from oil-containing raw materials using fatty acid ester as a solvent.

Background technique

The long-chain fatty acid esters produced by the transesterification reaction of bio-oil raw materials are a new type of pollution-free renewable energy, called biodiesel. Its combustion performance is comparable to that of traditional petroleum diesel, because the harmful substances in the exhaust gas emitted by the engine after combustion of biodiesel are 50% lower than that of traditional petrochemical diesel. At present, the research and application of biodiesel has received extensive attention (Huang Guoping, New Prospect of Oil Industry-Biodiesel, China Oil, 2003, 28 (4): 63-65; Hideki Fukuda et al, Biodiesel fuel production by transesterification of oils, J. Biosci. Bioeng., 2001, 92(5): 405-416).

At present, biodiesel is mainly produced by chemical method, that is, transesterification is carried out with animal and vegetable oils and some low-carbon alcohols (methanol or ethanol) under the action of alkali or acidic catalysts to generate corresponding fatty acid methyl esters or ethyl esters. There are some unavoidable disadvantages in the preparation of biodiesel by chemical method: ① The free fatty acid or water in the oil raw material seriously affects the progress of the reaction; ② The solubility of methanol in oil is not good, which easily leads to the formation of emulsion and complicates the subsequent treatment process ; ③ The amount of methanol required by the process greatly exceeds the reaction molar ratio, and the evaporation and reflux of excess methanol increases the energy consumption of the process.

Since biodiesel synthesis by biological methods has the advantages of mild reaction conditions, no pollutant emissions, free fatty acids in oil raw materials and a small amount of water do not affect enzymatic reactions, etc., it is in line with the development direction of green chemistry, and thus has attracted increasing attention (Yomi Watanabe et al, Continuous production of biodiesel fuel from vegetable oil using immobilized candida antarctica lipase, JAOCS, 2000, 7(4):355-358). In the production process of biodiesel produced by bio-enzyme method reported so far, some short-chain alcohols such as methanol, ethanol and other low-carbon alcohols are mainly used as acyl acceptors for the reaction. Direct use of these lower alcohols as reactive acyl acceptors to produce biodiesel has the following problems: these lower alcohols are toxic to enzyme molecules, thereby affecting the service life of enzymes; and directly using these lower alcohols as reactive acyl The acceptor produces biodiesel, and the by-product glycerol is produced during the reaction process, and the by-product glycerol can easily block the pore size of the immobilized enzyme, seriously affecting the enzyme reaction activity (Yuji Shimada et al, Enzymatic alcohol for biodiesel fuel production and application of the reaction to oil processing, Journal of Molecular Catalysis B: Enzymatic, 2002, 17:133-142).

This research group proposed a new method of using oil raw materials to synthesize biodiesel. This method is based on short-chain fatty acid ester RCOOR'(R, R' carbon number ranges from 1 to 4, such as methyl acetate, ethyl acetate etc.) as acyl acceptors, a new process for the conversion of renewable oil feedstocks to biodiesel. (Related patent application numbers are 03119600.4, 03150231.8 and PCT/CN2004/000051).

Contents of the invention

The purpose of the present invention is to propose a method for preparing biodiesel with short-chain fatty acid ester RCOOR' (R, R' carbon number range is 1-4, such as methyl acetate, ethyl acetate, etc.) as an acyl acceptor. A new process for extracting oil from oil-containing raw materials directly using short-chain fatty acid esters as solvents. It is characterized in that: the specific operation of the process is: add 120g of crushed oil-containing raw materials into 250mL of short-chain fatty acid ester RCOOR' with R and R' carbon numbers ranging from 1 to 4, mix, and shake for 20 to 40 minutes , based on the completeness of the oil extraction, vacuum filtration is carried out several times, and the ester mixture mainly including short-chain fatty acid esters and oil is extracted, and these ester mixtures can be further used in the preparation of biodiesel.

The short-chain fatty acid ester RCOOR' is methyl formate, methyl acetate, ethyl formate or ethyl acetate.

The oil-containing raw materials are soybean, rapeseed, peanut, cottonseed, oil palm and other oil-containing crops.

The beneficial effect of the present invention is that when using short-chain fatty acid esters as reactive acyl acceptors for biodiesel preparation, these short-chain fatty acid esters can be directly used to replace conventional extraction solvents such as n-hexane, etc. from oily raw materials such as soybeans and rapeseeds. The oil is extracted in the process, and the extracted ester mixture (mainly short-chain fatty acid ester and oil) can be further converted into biodiesel under the action of a catalyst. The new technology proposed by the invention directly utilizes these short-chain fatty acid esters to extract oil from oil-containing raw materials. The invention has excellent industrial application prospects no matter in terms of production technology or production cost.

Detailed ways

The present invention proposes a method of directly using short-chain fatty acid ester RCOOR' (R, R' carbon number range is 1-4, such as methyl acetate, ethyl acetate, etc.) as an acyl acceptor to prepare biodiesel Short-chain fatty acid esters are used as solvents to extract oil from oil-containing raw materials. The specific operation of the process is: add 120g of crushed oil-containing raw materials (soybean, rapeseed, peanut, cottonseed, oil palm and other oil-containing crops) to 250mL of R, R' short carbon atoms ranging from 1-4. Chain fatty acid ester RCOOR' (methyl formate, methyl acetate, ethyl formate or ethyl acetate) is mixed, shaken for 20 to 40 minutes, and vacuum filtered several times based on the completeness of the oil extraction. The extracted mainly includes The ester mixture of short-chain fatty acid ester and oil can be further used in the preparation of biodiesel.

Below only two examples are given to further illustrate the present invention, the present invention is not limited to these examples, and others similar to this process are not listed one by one.

Example 1: 120g of soybean powder was dissolved with 250mL of methyl acetate (or ethyl acetate) and n-hexane, placed on a shaker (150r/min, 30°C) for about 30 minutes, vacuum filtered, and then rotated in a vacuum An evaporator removes the solvent. Using methyl acetate (or ethyl acetate) as a solvent to extract soybean flour, 19% of oil (relative to the weight of soybeans) is extracted; compared with using n-hexane as a solvent to extract 18% of oil, the two effects are equivalent. It can be seen that methyl acetate (or ethyl acetate) can be directly used as a solvent for the effective extraction of soybean oil. Example 2: 120g of rapeseed was dissolved with 250mL of methyl formate (or ethyl formate) and n-hexane, placed on a shaker (150r/min, 30°C) and oscillated for about 30 minutes, vacuum filtered, and then rotated in a vacuum An evaporator removes the solvent. Using methyl formate (or ethyl formate) as a solvent to extract soybean flour, 32% of oil (relative to the weight of rapeseed) is extracted; using n-hexane as a solvent, extracting 33% of oil, the effect of the two is equivalent. It can be seen that methyl formate (or ethyl formate) can be directly used as a solvent for effective extraction of rapeseed oil.

Claims (3)

1. A new process of directly using short-chain fatty acid esters as a solvent to extract oil from oil-containing raw materials, characterized in that: the specific operation of the process is: adding 120g of crushed oil-containing raw materials into 250mL of R, R' carbon atoms Mix short-chain fatty acid esters in the range of 1-4 in RCOOR', shake for 20-40 minutes, and perform vacuum filtration several times based on the completeness of the oil extraction, and extract esters mainly including short-chain fatty acid esters and oils class mixture. 2. according to claim 1, directly use short-chain fatty acid esters as solvent extraction new technology of grease in oil-containing raw materials, it is characterized in that: described short-chain fatty acid esters RCOOR ' are methyl formate, methyl acetate, ethyl formate ester or ethyl acetate. 3. according to claim 1, directly use short-chain fatty acid esters as a solvent to extract the new oil and fat in oily raw materials, characterized in that: said oily raw materials are soybeans, rapeseeds, peanuts, cottonseeds, oil palms and other oils and fats crops.