CN112225659A

CN112225659A - Purification method of chromium propionate

Info

Publication number: CN112225659A
Application number: CN202011224388.5A
Authority: CN
Inventors: 唐卓; 刘永才; 黄生树; 李正; 彭青云
Original assignee: Jianming China Technology Co ltd
Current assignee: Jianming China Technology Co ltd
Priority date: 2020-11-05
Filing date: 2020-11-05
Publication date: 2021-01-15
Anticipated expiration: 2040-11-05
Also published as: CN112225659B

Abstract

The invention relates to the technical field of chromium propionate production, in particular to a purification method of chromium propionate, which comprises the following steps: s1, adding the crude chromium propionate into a mixed solvent of ethyl acetate and alcohols, and filtering; and S2, stirring, heating, drying, and recycling the solvent to obtain the chromium propionate crystal. The purity of the chromium propionate crystal obtained by the method is more than 99%, the content of impurity propionic acid is less than 0.5%, and the obtained crystal has uniform particle size distribution, good fluidity and low viscosity and is convenient for subsequent feed processing.

Description

Purification method of chromium propionate

Technical Field

The invention relates to the technical field of chromium propionate production, in particular to a purification method of chromium propionate.

Background

Chromium compounds have been used in the printing and tanning industry for a long time and are considered to be toxic and harmful elements, even carcinogens. Curran found until 1954 that the capacity of rat liver to synthesize cholesterol and fatty acids was enhanced by chromium supplementation, suggesting that chromium may be an essential trace element for animals. In 1959, Schwarz and Mertz isolated chromium-containing Glucose Tolerance Factor (GTF), demonstrating that chromium is an element essential for insulin to function during glucose metabolism, and also that chromium is an essential substance for insulin to promote fat synthesis. At present, chromium is considered one of the trace elements essential to humans and animals.

Research proves that the absorption rate of the organic chromium is higher than that of the inorganic chromium, the former is 10-25 percent, and the latter is 1-3 percent or lower. The FDA in the united states of america in 1 month of 1996 first allowed the use of chromium picolinate as a chromium source to be added to a daily ration for swine at an addition level of 200 μ g/kg, and thus most of the current research is focused on chromium picolinate and makes it the major source of chromium products on the market. However, since 1995, Stearns et al first reported that chromium picolinate could cause ovarian cell aberration in Chinese hamster, its safety was of concern and question. Microbiota chromium (TM) is the only organic chromium first approved by the U.S. FDA in 8 months in 2000 that can be used throughout a pig ration and is a feed additive product developed and produced autonomously by the U.S. institutional company. The main component of the feed is chromium propionate, which is a safe and efficient addition form of chromium in the feed and has higher biological value.

At present, the following two methods are mainly used for synthesizing chromium propionate: firstly, hexavalent chromium is used as a chromium source, and is reduced and then reacts with propionic acid to prepare the chromium-containing material (for example, patent CN 86100694A, EP 0897267 and RU 2694234); secondly, the compound is prepared by complexing propionic acid and soluble trivalent chromium salt in an aqueous solution (for example, patent CN 102351680A); for the purification of chromium propionate, in the prior art, ethanol is usually added after drying to fully dissolve the chromium propionate, filtering is performed, the filtrate is concentrated to be thick paste, the thick paste is placed in a vacuum drying oven for drying (such as patent CN 102351680a) or n-propanol is added, heating and stirring are performed until the thick paste is dissolved, filtering is performed, the filtrate is evaporated and concentrated to be paste, and centrifugal spray drying (such as CN 108147961a) is performed.

In order to solve the problems, the applicant unexpectedly finds that the solubility of chromium propionate in ethyl acetate is very low in the process of researching the properties of chromium propionate, and improves the purification process on the basis of the very low solubility, so that the purity of the obtained chromium propionate crystal is over 99 percent, the content of impurity propionic acid is less than 0.5 percent, and the obtained crystal has uniform particle size distribution, good fluidity and low viscosity and is convenient for subsequent feed processing.

Disclosure of Invention

The invention aims to solve the technical problem of providing a purification method of chromium propionate, wherein the purity of the obtained chromium propionate crystal is more than 99 percent, the content of impurity propionic acid is less than 0.5 percent, and the obtained crystal has uniform particle size distribution, good fluidity and low viscosity and is convenient for subsequent feed processing.

In order to solve the technical problems, the invention adopts the following technical scheme:

a method for purifying chromium propionate, comprising the steps of:

s1, adding the crude chromium propionate into a mixed solvent of ethyl acetate and alcohols, and filtering;

and S2, stirring, heating, drying, and recycling the solvent to obtain the chromium propionate crystal.

Preferably, the temperature-rising drying solvent recovery in step S2 adopts a staged mode:

s01, stirring for the first time, heating, evaporating and recovering the solvent 1;

and S02, continuously heating to the specified temperature, keeping the temperature constant, drying, and recycling the solvent 2 to obtain the chromium propionate crystal.

Preferably, the mixed solvent in S1 is a mixed solvent of ethyl acetate and an alcohol solvent.

Preferably, the alcoholic solvent is methanol, ethanol, n-propanol, isopropanol or n-butanol, preferably ethanol.

Preferably, the ratio of ethyl acetate to ethanol is 10:1 to 5:1, preferably 9: 1.

preferably, the temperature of the first temperature rise in the step S01 is 65 to 70 ℃.

Preferably, the temperature of the second temperature rise in the step S02 is 115-120 ℃.

The invention has the beneficial effects that:

1. by improving the solvent, the purity of the chromium propionate crystal is over 99 percent and the content of impurity propionic acid is less than 1 percent after one-time evaporation and drying; 2. according to the invention, ethyl acetate is used as a solvent, the solubility of chromium propionate in ethyl acetate is low, and the chromium propionate is separated out under the premise that the propionic acid can be dissolved during evaporation and separation, so that the propionic acid is prevented from being wrapped in the chromium propionate, and is convenient to further remove, and centrifugal spraying with high use cost is not required; 3. by adding ethanol as an auxiliary solvent, the dissolution of chromium propionate can be promoted, the chromium propionate is dispersed in ethyl acetate, the removal of propionic acid impurities is further promoted, the purity is further improved, the chromium propionate is distilled out by azeotropy with part of ethyl acetate in the evaporation process, and the wrapping of the chromium propionate on propionic acid is further reduced; 4. according to the purification process, the obtained crystals are high in purity, low in viscosity and good in fluidity, industrial production is facilitated, and the problem that the grinding equipment is blocked by the product in the grinding process is solved well.

Drawings

FIG. 1 is a diagram showing experimental results of dissolution of chromium propionate by different solvents according to the present invention;

Detailed Description

In order to facilitate understanding of those skilled in the art, the present invention will be further described with reference to the following examples and drawings, which are not intended to limit the present invention.

Example 1

Preparing a crude product: according to the method disclosed by the patent CN 102351680A, 5L of 40 mass percent chromium sulfate solution is measured, 16L of NaOH solution with the mass concentration of 5% is slowly added, stirring is carried out while adding, filtering is carried out, washing is carried out for 2-3 times by deionized water, drying is carried out to obtain gray green solid, 500g of the product in the last step is taken, added into a reaction kettle, 720mL of propionic acid is added, and stirring and heating are carried out for 1 hour at the temperature of 100 ℃. Filtering, removing insoluble substances, and concentrating to obtain thick paste to obtain crude chromium propionate, wherein the content of chromium propionate is 89% and the content of propionic acid is 6%.

Example 2

50g of the crude chromium propionate obtained in example 1 was added to a mixed solvent of 450mL of ethyl acetate and 50mL of ethanol, and filtered to obtain a clear solution. Stirring and heating, heating to 65-70 ℃ at a heating rate of 10 ℃/h, then keeping constant, distilling for about 2h, recovering the solvent for recycling, separating out a small amount of chromium propionate solid from the chromium propionate solution, heating to 115-120 ℃ at a speed of 60 ℃/h, drying, and recovering the solvent to obtain the chromium propionate crystal.

The purity of the obtained chromium propionate in the crystal is 99.5 percent, the content of the propionic acid is less than 0.3 percent, the granularity of the crystal is uniformly distributed, and the fluidity is good.

Example 3

50g of the crude chromium propionate obtained in example 1 was added to a mixed solvent of 450mL of ethyl acetate and 50mL of ethanol, and filtered to obtain a clear solution. Stirring and heating, heating to 120 ℃ at the heating rate of 60 ℃/h, drying, and recovering the solvent to obtain the chromium propionate crystal.

The purity of the obtained chromium propionate in the crystal is 98.9 percent, the content of the propionic acid is 0.7 percent, the granularity of the crystal is uniformly distributed, and the fluidity is good.

Example 4

Effect of different solvents on chromium propionate preparation:

50g of the crude chromium propionate obtained in the example are added to 500mL of solvent and filtered to give a clear solution. Stirring, heating to 120 ℃ at the speed of 60 ℃/h, drying, and recovering the solvent to obtain the chromium propionate crystal.

Example 5

Dissolution experiments of chromium propionate solids with different solvents

5g of the crude chromium propionate obtained in example 1 was taken, 50mL of organic solvent was added, and the mixture was dissolved by shaking for 30min, wherein the phenomenon of partial dissolution experiment is shown in FIG. 1, and the results are as follows:

group of	Solvent(s)	In the dissolved state
			1	Water (W)	Completely dissolve
2	Methanol	Completely dissolve
			3	Ethanol	Completely dissolve
4	N-propanol	Completely dissolve
			5	Isopropanol (I-propanol)	Completely dissolve
6	N-butanol	Completely dissolve
			7	Ethyl acetate	Insolubilizing a large amount of solids
8	Acetone (II)	Insolubilizing a large amount of solids

Comparative example 1

Preparing a crude product: according to the method disclosed by the patent CN 102351680A, 500mL of 40% chromium sulfate solution is measured, 1600mL of NaOH solution with the mass concentration not higher than 10% is slowly added while stirring, filtering is carried out, deionized water is used for washing for 2-3 times, drying is carried out to obtain a gray-green solid, 50.0g of the product in the last step is taken and added into a reaction kettle, 72mL of propionic acid is added, and stirring and heating are carried out for 1h at the temperature of 100 ℃. Filtering, removing insoluble substances, and concentrating to obtain thick paste to obtain crude chromium propionate, wherein the content of chromium propionate is 89% and the content of propionic acid is 6%.

Adding 50mL of absolute ethyl alcohol into the crude chromium propionate to fully dissolve the crude chromium propionate, filtering, concentrating the filtrate into thick paste, and drying in a vacuum drying oven at 50 ℃ for 8 hours to obtain green solid, wherein the purity of the obtained chromium propionate in the crystal is 97.0%, the content of propionic acid is 2.5%, the crystal is slightly viscous, and the fluidity is general.

Comparative example 2

Adding 50mL of n-propanol into the crude chromium propionate, heating, stirring until the n-propanol is dissolved, filtering, evaporating and concentrating the filtrate to be slurry, and carrying out centrifugal spray drying to obtain the chromium propionate. The purity of the obtained chromium propionate in the crystal is 96.5%, the content of the propionic acid is 2.8%, the crystal is more uniform and slightly viscous, and the fluidity is general.

The results of comparing examples 2 and 3 with comparative examples 1 and 2 clearly show that the experimental results of the examples of the present invention are clearly superior to those of the comparative examples.

Finally, it should be noted that the above-mentioned description is only a preferred embodiment of the present invention, and those skilled in the art can make various similar representations without departing from the spirit and scope of the present invention.

Claims

1. A method for purifying chromium propionate is characterized by comprising the following steps: the method comprises the following steps:

2. The method for purifying chromium propionate as claimed in claim 1, wherein: in the step S2, the temperature-raising drying solvent recovery adopts a segmented mode:

3. The method for purifying chromium propionate as claimed in claim 1, wherein: the mixed solvent in the S1 is a mixed solvent of ethyl acetate and an alcohol solvent.

4. The method of claim 3, wherein the purifying step comprises: the alcohol solvent is methanol, ethanol, n-propanol, isopropanol or n-butanol, preferably ethanol.

5. The method of claim 3, wherein the purifying step comprises: the ratio of ethyl acetate to ethanol is 10:1-5:1, preferably 9: 1.

6. the method for purifying chromium propionate as claimed in claim 2, wherein: the temperature of the first temperature rise in the step S01 is 65 to 70 ℃.

7. The method for purifying chromium propionate as claimed in claim 2, wherein: the temperature of the second temperature rise in the step S02 is 115-120 ℃.