A method for removing impurities from phosphoric acid catalyst used in pentamethylindane synthesis

Abstract

The invention discloses a method for removing impurities from a phosphoric acid catalyst used in pentamethylindane synthesis. The method comprises the following steps: S1, adding low-activity phosphoric acid of a certain concentration into a reactor, adding water into the phosphoric acid in proportion to dilute the phosphoric acid, adding a first extractant in a certain proportion to extract impurities from the diluted phosphoric acid, allowing the mixture to stand for stratification, pumping organic matter in an upper layer into a recovery kettle for recovery, and subjecting the phosphoric acid in the lower layer to secondary extraction; S2, adding a second extractant in a certain proportion to the phosphoric acid in the lower layer, allowing the mixture to stand for stratification, pumping the organic matter in the upper layer into a recovery kettle for recovery, and subjecting the phosphoric acid in the lower layer to further processing; S3, adding activated carbon in a certain proportion to decolorize the phosphoric acid in S2, filtering to obtain pure phosphoric acid, starting a system vacuum pump to perform negative pressure treatment on the reactor, starting stirring to stir the phosphoric acid, starting steam in the reactor jacket to heat the reactor, and removing water from the diluted phosphoric acid to 85% for reuse.

Description

Technical Field

[0001] The invention relates to the technical field of phosphoric acid impurity removal, in particular to a method for removing impurities from a phosphoric acid catalyst used in pentamethylindane synthesis. Background Art

[0002] Galaxolide was the first synthetic musk developed by International Flavors & Fragrances (IFF) in the 1960s. Its molecular weight is 258.4, its boiling point is 129°C (107 Pa), and its chemical name is 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-γ-2-benzopyran. It has a strong and persistent musky aroma with a woody undertone. It is widely used in cosmetics, soap fragrances, and other industries.

[0003] The main industrial route at present is to react α-methylstyrene and isopentene with phosphoric acid as a catalyst to produce pentamethylindane, and then the pentamethylindane and propylene oxide undergo Friedel-Crafts alkylation to produce hexamethylindanol, which is then reacted with methylal to produce the product galaxol. The reaction mechanism is as follows:

[0004]

[0005] In the actual industrial production of galaxolide, phosphoric acid is used as a catalyst for the synthesis of pentamethylindane. Due to the presence of styrene and isopentene impurities in the synthetic raw materials, the catalytic activity of phosphoric acid will decrease after a period of reaction due to the influence of impurities, which will then lead to a decrease in the yield of indane synthesis.

[0006] Therefore, in view of this, the inventors, based on their rich experience in design, development and actual production in the relevant industry for many years, have conducted research and improvements on the existing technology and its shortcomings, and provide a method for removing impurities from phosphoric acid catalysts used in the synthesis of pentamethylindane, in order to achieve a more practical purpose. Summary of the Invention

[0007] In order to solve the problem mentioned in the above background technology that the catalytic phosphoric acid in the indane reaction is affected by impurities in the raw materials after a period of reaction, resulting in a decrease in catalytic activity and thus a decrease in the indane synthesis yield, the present invention provides a method for removing impurities from the phosphoric acid catalyst in the pentamethylindane synthesis.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A method for removing impurities from a phosphoric acid catalyst used in pentamethylindane synthesis comprises the following steps:

[0010] S1. Add a certain concentration of low-activity phosphoric acid into a reactor, add water to the phosphoric acid in proportion to dilute the phosphoric acid, then add a certain proportion of a first extractant to extract impurities from the diluted phosphoric acid, then allow the mixture to stand and separate, pump the upper layer of organic matter into a recovery kettle for recovery, and perform secondary extraction on the lower layer of phosphoric acid;

[0011] S2, adding a certain proportion of the second extractant to the lower phosphoric acid, allowing it to stand for stratification, and then pumping the upper organic matter into a recovery kettle for recovery, while the lower phosphoric acid is further processed;

[0012] S3. Add activated carbon in proportion to decolorize the phosphoric acid in S2, and obtain pure phosphoric acid through filtration. Turn on the system vacuum pump to negatively pressure the reactor, turn on the stirring to stir the phosphoric acid, turn on the steam in the reactor jacket to heat the reactor, and remove water from the diluted phosphoric acid to 85% before reuse.

[0013] Preferably, the low-activity phosphoric acid in step S1 contains 80-85% phosphoric acid, 10-5% water, 2-3% styrene polymer, 2-3% isopentene polymer, and 2-3% indane.

[0014] Preferably, the mass ratio of water to phosphoric acid in step S1 is 2-3:1.

[0015] Preferably, the first extractant in step S1 is 99.9% pure chlorobenzene, with a mass ratio of 0.3-0.5:1. 99.9% pure chlorobenzene is used to remove impurities from phosphoric acid. The density of chlorobenzene is very close to that of styrene and isopentene, and styrene and isopentene impurities can be effectively removed, thereby improving the catalytic activity of phosphoric acid and increasing the system reaction yield.

[0016] Preferably, the second extractant in step S2 is 99.9% pure cyclohexane with a mass ratio of 0.5-0.8:1. 99.9% pure cyclohexane is a non-polar solvent and can be used to extract low-polarity organic matter, such as styrene and isopentene.

[0017] Preferably, in step S3, the mass ratio of activated carbon to phosphoric acid is 0.05-0.1:1.

[0018] Preferably, in step S3, the vacuum pump pressure is controlled at -95 KPa to -92 KPa, and the stirring speed is 0.1 to 2 m / s;

[0019] Preferably, in step S3, the steam temperature of the reactor jacket is 60-80°C.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. After using chlorobenzene to remove impurities from phosphoric acid, the catalytic activity of phosphoric acid is improved, and the system reaction yield is higher.

[0022] 2. Using chlorobenzene, a solvent in Galax synthesis, to remove impurities from phosphoric acid, a catalyst in indane synthesis, improves the catalytic activity of phosphoric acid, optimizes the reaction efficiency and material utilization of the entire production process, and significantly increases the company's economic benefits.

[0023] In summary, the present invention overcomes the shortcomings of the prior art. The method can restore the catalytic activity of phosphoric acid, improve the reaction yield, realize the recycling of the catalyst, reduce production costs, and significantly improve production efficiency. At the same time, the entire production process is optimized for reaction efficiency and material utilization, thereby increasing the economic benefits of the enterprise and having high social use value and application prospects. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0025] Unless otherwise specified, the raw materials used in the present invention are all conventional products purchased from the market.

[0026] The 99.9% pure chlorobenzene was purchased from Aladdin, CAS number: 108-90-7;

[0027] 99.9% pure cyclohexane was purchased from Aladdin, CAS number: 110-82-7;

[0028] Activated carbon was purchased from Aladdin, CAS number: 7440-44-0.

[0029] Example 1

[0030] Add 2000kg of low-activity phosphoric acid to a 10000L reactor, add 4000kg of pure water in a 2:1 ratio to the reactor, and stir to dilute.

[0031] 600 kg of 99.9% pure chlorobenzene solvent was added to the phosphoric acid at a ratio of 0.3:1 to extract impurities. The extraction was carried out for 2 hours. After the extraction was completed, the chlorobenzene solvent was allowed to stand and separate. The upper layer was sent to a distillation tower for distillation recovery.

[0032] The phosphoric acid in the lower layer was further extracted by adding 1000 kg of pure cyclohexane with a concentration of 99.9% at a ratio of 0.5:1 for 2 hours. After the extraction, the phosphoric acid was allowed to stand and separate. 100 kg of activated carbon was added to the phosphoric acid in the lower layer at a ratio of 0.05:1 for adsorption and decolorization.

[0033] After decolorization, the system vacuum pump is turned on to reduce the pressure of the reactor to -95kPa, the stirring is turned on to stir the phosphoric acid, the steam in the reactor jacket is turned on, the reactor is heated to 60 degrees to remove water, and the diluted phosphoric acid is reused after the water content is reduced to 85%.

[0034] Example 2

[0035] Add 2000kg of low-activity phosphoric acid to a 10000L reactor, add 6000kg of pure water in a 3:1 ratio to the reactor, and stir to dilute.

[0036] 800 kg of 99.9% pure chlorobenzene solvent was added to the phosphoric acid at a ratio of 0.4:1 to extract impurities. The extraction was carried out for 2 hours. After the extraction was completed, the chlorobenzene solvent was allowed to stand and separate. The upper layer was sent to a distillation tower for distillation recovery.

[0037] The phosphoric acid in the lower layer was further extracted with 1400 kg of pure cyclohexane with a concentration of 99.9% at a ratio of 0.7:1 for 2 hours. After the extraction, the phosphoric acid was allowed to stand and separate. 100 kg of activated carbon was added to the phosphoric acid in the lower layer at a ratio of 0.05:1 for adsorption and decolorization.

[0038] After decolorization, the system vacuum pump is turned on to reduce the pressure of the reactor to -92kPa, the stirring is turned on to stir the phosphoric acid, the steam in the reactor jacket is turned on, the reactor is heated to 70 degrees to remove water, and the diluted phosphoric acid is reused after the water content is reduced to 85%.

[0039] Example 3

[0040] Add 2000kg of low-activity phosphoric acid to a 10000L reactor, add 5000kg of pure water in a ratio of 2.5:1 to the reactor, and stir to dilute.

[0041] 1000 kg of 99.9% pure chlorobenzene solvent was added to the phosphoric acid at a ratio of 0.5:1 to extract impurities. The extraction was carried out for 2 hours. After the extraction was completed, the chlorobenzene solvent was allowed to stand and separate. The upper layer was sent to a distillation tower for distillation recovery.

[0042] The phosphoric acid in the lower layer was further extracted with 1600 kg of pure cyclohexane with a concentration of 99.9% at a ratio of 0.8:1 for 2 hours. After the extraction, the phosphoric acid was allowed to stand and separate. 100 kg of activated carbon was added to the phosphoric acid in the lower layer at a ratio of 0.05:1 for adsorption and decolorization.

[0043] After decolorization, the system vacuum pump is turned on to reduce the pressure of the reactor to -92kPa, the stirring is turned on to stir the phosphoric acid, the steam in the reactor jacket is turned on, the reactor is heated to 60 degrees to remove water, and the diluted phosphoric acid is dehydrated to 85% before reuse.

[0044] Table 1 Phosphoric acid impurity removal effect in different examples

[0045] Phosphoric acid catalytic yield before impurity removal Phosphoric acid catalytic yield after impurity removal Example 1 50％ 58％ Example 2 51％ 59％ Example 3 53％ 60％

[0046] As shown in Table 1, the organic impurities in phosphoric acid can be removed by combined extraction with chlorobenzene and cyclohexane, thereby restoring the catalytic activity of phosphoric acid, improving the reaction yield, realizing the recycling of the catalyst, and reducing the production cost.

[0047] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for removing impurities from a phosphoric acid catalyst used in the synthesis of pentamethylindane, characterized in that: The following steps are involved: S1. Add a certain concentration of low-activity phosphoric acid into a reactor, add water to the phosphoric acid in proportion to dilute the phosphoric acid, then add a certain proportion of a first extractant to extract impurities from the diluted phosphoric acid, then allow the mixture to stand and separate, pump the upper layer of organic matter into a recovery kettle for recovery, and perform secondary extraction on the lower layer of phosphoric acid; S2, adding a certain proportion of the second extractant to the lower phosphoric acid, allowing it to stand for stratification, and then pumping the upper organic matter into a recovery kettle for recovery, while the lower phosphoric acid is further processed; S3. Add activated carbon in proportion to decolorize the phosphoric acid in S2, obtain pure phosphoric acid through filtration, start the system vacuum pump to negatively pressure the reactor, start stirring to stir the phosphoric acid, start the reactor jacket steam to heat the reactor, remove water from the diluted phosphoric acid to 85% and then reuse; In step S1, the first extractant is pure chlorobenzene with a concentration of 99.9% and a mass ratio of 0.3-0.5:1; In step S2, the second extractant is pure cyclohexane with a concentration of 99.9% and a mass ratio of 0.5-0.8:

1.

2. A method for removing impurities from a phosphoric acid catalyst used in the synthesis of pentamethylindane according to claim 1, characterized in that: The low-activity phosphoric acid in step S1 contains 80-85% phosphoric acid, 10-5% water, 2-3% styrene polymer, 2-3% isopentene polymer, and 2-3% indane.

3. A method for removing impurities from a phosphoric acid catalyst used in the synthesis of pentamethylindane according to claim 1, characterized in that: In step S1, the mass ratio of water to phosphoric acid is 2-3:

1.

4. A method for removing impurities from a phosphoric acid catalyst used in the synthesis of pentamethylindane according to claim 1, characterized in that: In step S3, the mass ratio of activated carbon to phosphoric acid is 0.05-0.1:

1.

5. A method for removing impurities from a phosphoric acid catalyst used in the synthesis of pentamethylindane according to claim 1, characterized in that: In step S3, the vacuum pump pressure is controlled at -95 KPa to -92 KPa, and the stirring speed is 0.1 to 2 m / s.

6. A method for removing impurities from a phosphoric acid catalyst used in pentamethylindane synthesis according to claim 1, characterized in that: In step S3, the steam temperature of the reactor jacket is 60-80°C.

Images