A crystallization process for ethyl maltol

Abstract

The invention belongs to the technical field of ethyl maltol refining, and provides an ethyl maltol crystallization process, which specifically comprises the following steps: (1) placing a crude ethyl maltol product in water, heating and dissolving it, and then cooling and crystallizing it to obtain an ethyl maltol crystal product; (2) centrifuging the ethyl maltol crystal product obtained in step (1) to remove impurities, and obtain an impurity-removed ethyl maltol crystal product; (3) placing the impurity-removed ethyl maltol crystal product in step (2) in a mixed solvent of n-propanol and water, stirring it until it is completely dissolved, and then cooling and crystallizing it at a certain cooling rate, and finally obtaining ethyl maltol crystal particles. The obtained ethyl maltol crystal product presents uniform granular crystals, has a pure aroma, a low impurity content, and low energy consumption.

Description

Technical Field

[0001] The invention relates to the technical field of ethyl maltol purification, and in particular to an ethyl maltol crystallization process. Background Art

[0002] Ethyl maltol is an ideal food additive and flavor enhancer, which can mask odor, preserve flavor, and its flavoring effect is six times that of methyl maltol and twenty-four times that of coumarin. Ethyl maltol is widely used in cosmetics, beverages, food, toothpaste, cigarettes, and medicines. In the industrial production of ethyl maltol, the intermediate furanol is generally prepared by Grignard reaction, and furanol is then subjected to chlorination and hydrolysis reactions to prepare crude ethyl maltol. The crude ethyl maltol is then recrystallized to obtain refined ethyl maltol. It can be seen that the synthesis technology of ethyl maltol has been well mastered in my country, but the crystallization process currently used still has defects to varying degrees. For example: The invention patent with application number 202210125031.4 discloses a method for separating and purifying ethyl maltol. The patent cools and crystallizes the crude ethyl maltol. After the product is centrifuged and dried, it is rinsed with ethanol to remove organic impurities on the product. The product is then dissolved in alcohol, centrifuged and dried, and then rinsed with pure water to remove water-soluble impurities. Although this patent can also achieve the purpose of separation and purification, the product obtained by this process has a poor crystal form, which is generally needle-shaped or large particles. The crystallized product is wrapped with certain impurities and has a poor aroma. Alcohol is used to dissolve the material during the crystallization process, resulting in a large consumption of ethanol, which increases the production cost of the product. In addition, the material sticks to the crystallization kettle during the crystallization process, which seriously affects the crystallization effect. Summary of the Invention

[0003] In view of this, the present invention provides an ethyl maltol crystallization process, which comprises the following steps: firstly dissolving a crude ethyl maltol product in water, then slowly cooling and crystallizing the product using brine, drying the crystallized product using a centrifuge to remove a certain amount of impurities; then dissolving the impurity-removed crystallized product using a mixed solvent of n-propanol and water, and subjecting the dissolved material to a cooling and crystallization treatment. By controlling the cooling rate, a plurality of crystal nuclei are formed, and the crystal nuclei slowly crystallize to form better crystalline particles.

[0004] The present invention provides an ethyl maltol crystallization process, comprising the following steps:

[0005] (1) placing crude ethyl maltol in water and heating to dissolve it, then cooling it down to crystallize it, to obtain a crystalline ethyl maltol product;

[0006] (2) centrifuging the ethyl maltol crystalline product obtained in step (1) to remove impurities, thereby obtaining a cleaned ethyl maltol crystalline product;

[0007] (3) placing the ethyl maltol crystalline product after impurity removal in step (2) in a mixed solvent of n-propanol and water, stirring until it is completely dissolved, and then cooling and crystallizing at a certain cooling rate to finally obtain ethyl maltol crystalline particles.

[0008] Preferably, the heating temperature in step (1) is 80-120°C.

[0009] Preferably, the specific steps of cooling and crystallizing in step (1) are: using frozen brine with a temperature of -15°C to -5°C to slowly cool to 0°C, controlling the cooling rate to 0.3-0.6°C / min, cooling to obtain ethyl maltol crystal product.

[0010] Preferably, the centrifugal speed in step (2) is 1000-1100 r / min.

[0011] Preferably, the mass ratio of the mixed solvent in step (3) to the ethyl maltol crystalline product after impurity removal is 1:2.

[0012] Preferably, the mass ratio of n-propanol to water in the mixed solvent in step (3) is 8-10:5-7.

[0013] Preferably, the stirring rate in step (3) is 500-800 r / min.

[0014] Preferably, the cooling rate in step (3) is 0.2-0.5°C / min.

[0015] Preferably, the system temperature is reduced to 0°C after the cooling crystallization in step (3).

[0016] Compared with the prior art, the present invention has the following beneficial effects: the ethyl maltol crystal product has granular crystals, the crystal particles are uniform, the product has a pure aroma, the impurity content is low, and the energy consumption of the preparation method is significantly reduced. DETAILED DESCRIPTION

[0017] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

[0018] Unless otherwise specified, the experimental methods or test methods described in the following examples are all conventional methods; the raw materials and auxiliary agents, unless otherwise specified, are all obtained from conventional commercial channels or prepared by conventional methods.

[0019] Example 1

[0020] An ethyl maltol crystallization process is prepared by the following steps:

[0021] (1) placing 1 t of crude ethyl maltol in 2 t of water and heating to 80° C. to completely dissolve the crude ethyl maltol, then slowly cooling to 0° C. using -15° C. brine at a cooling rate of 0.6° C. / min, and crystallizing by cooling to obtain a crystalline ethyl maltol product;

[0022] (2) centrifuging the ethyl maltol crystalline product obtained in step (1) to remove a certain amount of impurities, wherein the centrifugal speed is 1000 r / min, to obtain the impurity-removed ethyl maltol crystalline product;

[0023] (3) placing the ethyl maltol crystalline product after impurity removal in step (2) in a mixed solvent of n-propanol and water, stirring at a speed of 800 r / min until it is completely dissolved, wherein the ratio of the mixed solvent of n-propanol and water to the ethyl maltol crystalline product after impurity removal is 1:2, and the mass ratio of n-propanol to water in the mixed solvent is 8:5; then performing a cooling crystallization treatment, controlling the cooling rate to 0.2°C / min, so that the system temperature is reduced to 0°C, to obtain ethyl maltol crystalline particles.

[0024] The obtained ethyl maltol crystalline particles have a purity of 98.5%, have granular crystals, and are uniform. The 60-mesh pass rate of the ethyl maltol crystalline particles is 89%, and the 40-mesh pass rate is 98%. The ethyl maltol crystalline particles have a pure aroma, a low impurity content, and significantly reduced energy consumption.

[0025] Example 2

[0026] An ethyl maltol crystallization process is prepared by the following steps:

[0027] (1) placing 1 t of crude ethyl maltol in 2 t of water and heating to 120° C. to completely dissolve the crude ethyl maltol, then slowly cooling to 0° C. using -5° C. brine at a cooling rate of 0.3° C. / min, and crystallizing by cooling to obtain a crystalline ethyl maltol product;

[0028] (2) centrifuging the ethyl maltol crystalline product obtained in step (1) to remove a certain amount of impurities, wherein the centrifugal speed is 1100 r / min, to obtain the impurity-removed ethyl maltol crystalline product;

[0029] (3) placing the ethyl maltol crystalline product after impurity removal in step (2) in a mixed solvent of n-propanol and water, stirring at a speed of 700 r / min until it is completely dissolved, wherein the ratio of the mixed solvent of n-propanol and water to the ethyl maltol crystalline product after impurity removal is 1:2, and the mass ratio of n-propanol to water in the mixed solvent is 10:7; then performing a cooling crystallization treatment, controlling the cooling rate to 0.5°C / min, so that the system temperature is reduced to 0°C, and finally obtaining ethyl maltol crystalline particles.

[0030] The obtained ethyl maltol crystalline particles have a purity of 98.7%, have granular crystals, and are uniform. The 60-mesh pass rate of the ethyl maltol crystalline particles is 88%, and the 40-mesh pass rate is 96%. The ethyl maltol crystalline particles have a pure aroma, a low impurity content, and significantly reduced energy consumption.

[0031] Example 3

[0032] An ethyl maltol crystallization process is prepared by the following steps:

[0033] (1) placing 1 ton of crude ethyl maltol in 2 ton of water and heating it to 100° C. to completely dissolve the crude ethyl maltol, then slowly cooling the mixture to 0° C. using -10° C. brine at a cooling rate of 0.5° C. / min, and crystallizing the mixture by cooling to obtain a crystalline ethyl maltol product;

[0034] (2) centrifuging the ethyl maltol crystalline product obtained in step (1) to remove a certain amount of impurities, wherein the centrifugal speed is 1100 r / min, to obtain the impurity-removed ethyl maltol crystalline product;

[0035] (3) placing the ethyl maltol crystalline product after impurity removal in step (2) in a mixed solvent of n-propanol and water, stirring at a speed of 800 r / min until it is completely dissolved, wherein the ratio of the mixed solvent of n-propanol and water to the ethyl maltol crystalline product after impurity removal is 1:2, and the mass ratio of n-propanol to water in the mixed solvent is 9:7; then performing a cooling crystallization treatment, controlling the cooling rate to 0.3°C / min, so that the system temperature is reduced to 0°C, and finally obtaining ethyl maltol crystalline particles.

[0036] The obtained ethyl maltol crystalline particles have a purity of 97.5%, have granular crystals, and are uniform. The 60-mesh pass rate of the ethyl maltol crystalline particles is 86%, and the 40-mesh pass rate is 95%. The ethyl maltol crystalline particles have a pure aroma, a low impurity content, and significantly reduced energy consumption.

[0037] Comparative Example 1

[0038] The difference from Example 1 is that the mixed solvent of n-propanol and water in step (3) is replaced by water, and the remaining steps and parameters are the same as those in Example 1.

[0039] Comparative Example 2

[0040] The difference from Example 1 is that the stirring speed in step (3) is set to 900 r / min, and the remaining steps and parameters are the same as those in Example 1.

[0041] Comparative Example 3

[0042] The difference from Example 1 is that the stirring speed in step (3) is set to 400 r / min, and the remaining steps and parameters are the same as those in Example 1.

[0043] Comparative Example 4

[0044] The difference from Example 1 is that the cooling rate in step (3) is 0.1°C / min, and the remaining steps and parameters are the same as those in Example 1.

[0045] Comparative Example 5

[0046] The difference from Example 1 is that the cooling rate in step (3) is set to 0.6°C / min, and the remaining steps and parameters are the same as those in Example 1.

[0047] Analysis shows that the purity and uniformity of the ethyl maltol crystalline particles obtained in Comparative Examples 1-5 are lower than those in Examples 1-3.

[0048] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A crystallization process for ethyl maltol, characterized in that: Prepared by the following steps: (1) 1 t of crude ethyl maltol was placed in 2 t of water and heated to 80°C to completely dissolve the crude ethyl maltol. The mixture was then slowly cooled to 0°C using -15°C brine at a cooling rate of 0.6°C / min. Crystallization was performed by cooling to obtain a crystalline ethyl maltol product. (2) centrifuging the ethyl maltol crystalline product obtained in step (1) to remove a certain amount of impurities, wherein the centrifugal speed is 1000 r / min, to obtain the impurity-removed ethyl maltol crystalline product; (3) placing the ethyl maltol crystalline product after impurity removal in step (2) in a mixed solvent of n-propanol and water, stirring at a speed of 800 r / min until it is completely dissolved, wherein the ratio of the mixed solvent of n-propanol and water to the ethyl maltol crystalline product after impurity removal is 1:2, and the mass ratio of n-propanol to water in the mixed solvent is 8:5; then performing a cooling crystallization treatment, controlling the cooling rate to 0.2°C / min, so that the system temperature is reduced to 0°C, to obtain ethyl maltol crystalline particles.