Method for purifying 4, 4 '-dihydroxybiphenyl
By using a mixed polar and non-polar solvent system with heating reflux and solvent exchange, the problem of low purity and yield of 4,4'-dihydroxybiphenyl was solved, achieving efficient purification and improved equipment utilization.
Patent Information
- Application Number
- CN202511248583.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-03
- Publication Date
- 2025-12-12
AI Technical Summary
The purity and yield of 4,4'-dihydroxybiphenyl in the existing production process are low. The traditional refining process is inefficient and the residue is difficult to handle after the final solvent recovery, resulting in a low product yield.
A mixed solvent system of polar and non-polar solvents is used to purify 4,4'-dihydroxybiphenyl by heating and reflux and solvent exchange. The process includes heating and reflux, filtration and solvent replenishment steps. High purity of over 99.8% and yield of over 95% can be achieved in two operations.
Rapid purification of high-purity 4,4'-dihydroxybiphenyl was achieved, increasing equipment utilization by 2.5 times and reducing equipment investment costs.
Smart Images
Figure CN121107953A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of purification technology, in particular to a method for purifying 4,4'-dihydroxybiphenyl. BACKGROUND
[0002] 4,4'-dihydroxybiphenyl is a very widely used fine organic chemical raw material, 4,4'-dihydroxybiphenyl has good heat resistance, non-pollution, antioxidant and anti-aging effect, and is widely used in the preparation of engineering composite materials, polyesters, polyurethanes, polyphenyl sulfone, epoxy resin and other modified monomers with excellent performance in the chemical industry, and has a wide range of uses in the chemical and pharmaceutical industries.
[0003] The current production process is biphenyl sulfonation, alkali fusion, acidification and refining. The purity of 4,4'-dihydroxybiphenyl after alkali fusion is 90%, and the purity of 4-hydroxybiphenyl is 8%. The traditional process uses methanol for refining, and the yield is low, the efficiency is low, and the purity and content have certain problems. The traditional process needs 5 times of refining to reach the requirement of 99.8% of the polymerization material, and the residue mixture after solvent recovery cannot be effectively treated, resulting in low product yield of 70%. SUMMARY
[0004] The purpose of the present application is to provide a method for purifying 4,4'-dihydroxybiphenyl, which can reach a purity of more than 99.8% in two times, has a higher content than the market, and has a 4,4'-dihydroxybiphenyl yield of more than 95%, and the equipment utilization rate is increased to 2.5 times of the original, thereby reducing the equipment investment rate.
[0005] The technical scheme of the present application is as follows:
[0006] The present application provides a method for purifying 4,4'-dihydroxybiphenyl, which comprises the following steps: dissolving 4,4'-dihydroxybiphenyl crude product in a mixed solvent of a polar solvent and a non-polar solvent, heating and refluxing, recovering part of the polar solvent, supplementing the non-polar solvent, cooling, and filtering to obtain high-purity 4,4'-dihydroxybiphenyl.
[0007] As a further improvement of the present application, the polar solvent is selected from at least one of methanol, ethanol, and acetone.
[0008] As a further improvement of the present application, the non-polar solvent is at least one of toluene, xylene, mesitylene, ethylbenzene, and cyclohexane.
[0009] As a further improvement of the present application, the volume ratio of the polar solvent to the non-polar solvent is 3-5:7-5.
[0010] As a further improvement of the present application, the volume ratio of the polar solvent to the non-polar solvent is 1:1.
[0011] As a further improvement of the present application, the purity of the high-purity 4,4'-dihydroxybiphenyl is greater than 99.8%.
[0012] As a further improvement of the present application, the heating reflux time is 0.5-1h.
[0013] The present application has the following advantages: the present application adopts the method of dissolving the crude product with mixed solvent of polar solvent and non-polar solvent, recovering part of the polar solvent and supplementing the non-polar solvent, which can reach the purity of more than 99.8% in two times, the content is higher than the market, the yield of 4,4'-dihydroxybiphenyl is more than 95%, the equipment utilization rate is increased to 2.5 times of the original, and the equipment investment rate is reduced. BRIEF DESCRIPTION OF DRAWINGS
[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.
[0015] Figure 1 The liquid chromatography result of 4,4'-dihydroxybiphenyl purified in Example 1;
[0016] Figure 2 The liquid chromatography result of 4,4'-dihydroxybiphenyl purified in Example 2. DETAILED DESCRIPTION
[0017] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.
[0018] Example 1
[0019] Raw material: crude product 100g, 4,4'-dihydroxybiphenyl accounts for 90%, 4-hydroxybiphenyl accounts for 9%.
[0020] Experimental method: under the protection of nitrogen, add 5 times the weight of the crude product of ethanol 500g, 5 times the weight of mesitylene 500g, into a 2000ml four-necked flask, heat to reflux for 0.5h, recover 300g of solvent, while slowly supplementing 300g of mesitylene, slowly cool to 40℃, filter. The filtrate is recovered by solvent, and the filter residue is recovered by 4-hydroxybiphenyl; the filter cake is dissolved with 10 times of mesitylene ethanol solvent (5:5), and the above operation is repeated, and the filter cake is obtained by cooling and filtering, with a yield of 85.5g, a purity of 95%, and a purity of 99.9%, and its gas chromatogram is as shown in Figure 1 Compared with the same kind of product on the market, the content is 103%, and the filtrate is recovered by solvent.
[0021] Example 2
[0022] Raw material: crude product 100g, of which 4,4'-dihydroxybiphenyl is 90%, and 4-hydroxybiphenyl accounts for 9%.
[0023] Experimental method: under the protection of nitrogen, add 5 times the weight of the crude product of ethanol 500g, 5 times the weight of mesitylene 500g, into a 2000ml four-necked flask, heat to reflux for 0.5h, recover 300g of solvent, while slowly supplementing 300g of mesitylene, slowly cool to 40℃, filter. The filtrate is recovered by solvent, and the filter residue is recovered by 4-hydroxybiphenyl; the filter cake is dissolved with 10 times of mesitylene ethanol solvent (5:5), and the above operation is repeated, and the filter cake is obtained by cooling and filtering, with a yield of 85.5g, a purity of 95%, and a purity of 99.9%, and its gas chromatogram is as shown in Figure 2 Compared with the same kind of product on the market, the content is 102%, and the filtrate is recovered by solvent.
[0024] The above only describes the preferred embodiments of the present application and does not limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.
Claims
1. A process for purifying 4,4'-dihydroxydiphenyl, characterized in that, The crude 4,4'-dihydroxybiphenyl is dissolved in a mixed solvent of a polar solvent and a non-polar solvent, heated to reflux, part of the polar solvent is recovered, and the non-polar solvent is supplemented, cooled, and filtered to obtain high-purity 4,4'-dihydroxybiphenyl.
2. The method of claim 1, wherein, The polar solvent is at least one selected from methanol, ethanol, and acetone.
3. The method of claim 1, wherein, The non-polar solvent is at least one selected from toluene, xylene, mesitylene, ethylbenzene, and cyclohexane.
4. The method of claim 1, wherein, The volume ratio of the polar solvent to the non-polar solvent is 3-5:7-5.
5. The method of claim 1, wherein, The volume ratio of the polar solvent to the non-polar solvent is 1:
1.
6. The method of claim 1, wherein, The purity of the high-purity 4,4'-dihydroxybiphenyl is greater than 99.8%.
7. The method of claim 1, wherein, The heating reflux time is 0.5-1 h.