Preparation method of isopimaric acid
By preparing ammonium salt salt of thermor and spice of pine or rosin, and for ammonium salt salt salt, and duplex crystallization and acidification treatment, the existing technologies are solved. , Achieve high purity and high efficiency preparation.
Patent Information
- Application Number
- CN202411480467.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-23
- Publication Date
- 2025-01-24
AI Technical Summary
In the prior art, the preparation cost of isosteine acid is high, the yield is low, and there is a lack of high purity industrial-grade products.
After the heat -heterogeneity is used to prepare the heterogeneous heterogeneity, the alcohol ammonium salt salt is preserved with the sedimentation method of isot butanol, and the steps are purified by duplex heavy crystallization, washing and pulp. Essence
The high -purity preparation of the aliens (the purity can reach 96%), which reduces the production cost, increases the rate of gain, and simplifies the operation steps.
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Figure CN119350160A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for preparing isopimaric acid which is an important component of rosin or rosin. Background Art
[0002] Isopimaric acid is an important component of rosin or rosin, and its content in slash pine rosin is about 20%. The stable phenanthrene ring skeleton structure and unique exocyclic double bonds of isopimaric acid give it a variety of chemical reaction characteristics. Therefore, the separation and purification of isopimaric acid from typical rosin or rosin is of great significance for the development and utilization of pimaric acid-type resin acids.
[0003] There are three types of methods for separating and purifying isopimaric acid known at present, namely: "piperidine precipitation method", "maleic anhydride addition-isobutanolamine precipitation method" and "distillation method". Loeblich et al. reported direct precipitation using piperidine. This method directly separates the ammonium salt of isopimaric acid from the rosin raw material, and the operation is simple. The disadvantage is that although piperidine is selective for isopimaric acid, the crystallization rate of the ammonium salt of isopimaric acid generated is very slow, the production cycle is long and the yield is low. Harris et al. removed abietic acid-type resin acid by Diels-Alder addition reaction of maleic anhydride, and then obtained isopimaric acid by selective precipitation of isobutanolamine, and the yield of isopimaric acid was 8%. In this method, it is difficult to separate maleopimaric acid from unreacted resin acid (including pimaric acid-type resin acid, dehydroabietic acid and a small amount of unreacted abietic acid-type resin acid), and the separated unreacted resin acid is easily mixed with maleopimaric acid. Harris et al. also used a distillation method to directly evaporate pimaric acid and isopimaric acid, and then separated isopimaric acid with isobutanolamine. This method requires high distillation conditions, is not conducive to operation, and the yield of isopimaric acid is low.
[0004] At present, there are few research reports on the separation and purification of isopimaric acid in China, and there is no industrial-grade high-purity isopimaric acid product. Therefore, exploring efficient, high-yield, and economically feasible methods for separating isopimaric acid will accelerate the application of isopimaric acid in the fields of medicine, biology, and materials. Summary of the invention
[0005] In order to solve the shortcomings of high cost and low yield of preparing isopimaric acid in the prior art methods, the present invention provides a method for preparing isopimaric acid with low production cost and high yield, and the purity of the product isopimaric acid is also high, which can reach 96%.
[0006] The main technical route adopted by the present invention is as follows:
[0007] Rosin or rosin → thermal isomerized rosin → isopimaric acid ammonium salt → purified ammonium salt → acidified isopimaric acid
[0008] The technical solution of the present invention is: a method for preparing isopimaric acid, comprising the following steps:
[0009] S1: Dissolve the thermal isomerized rosin made of any one of rosin and rosin containing isopimaric acid in 1-10 times the mass of acetone, add dropwise an acetone solution of isobutanolamine equivalent to 1-40% of the mass of the thermal isomerized rosin, acetone / isobutanolamine=1:1mL / g, form a precipitate, let stand, filter, wash with 50% by volume ethanol, and dry to obtain a crude isopimaric acid ammonium salt; the crude isopimaric acid ammonium salt is prepared by a compound recrystallization method, a washing method, and a beating method, wherein each group of isopimaric acid ammonium salt is first washed once, beaten and dried once, and then recrystallized and dried four times to obtain purified isopimaric acid ammonium salt crystals;
[0010] S2: dissolving the purified isopimaric acid ammonium salt crystals obtained in S1 in 1 to 20 times the mass of n-hexane, adding hydrochloric acid with a mass fraction of 1 to 20% in portions until the isopimaric acid ammonium salt crystals disappear, separating the water layer, washing the n-hexane layer with water until neutral, distilling off the n-hexane at 65 to 85° C. under one atmosphere, dissolving the residue in 0.5 to 5 times the mass of acetone, slowly dripping water into the solution until the precipitated crystals no longer increase, filtering and drying to obtain purified isopimaric acid.
[0011] The solvents used in the double recrystallization method include ethanol, ethyl acetate and methanol with a volume fraction of 95%; the volume ratio of the pulping solvent is ethyl acetate: methyl tert-butyl ether: ethanol = 5:5:1, and the isopimaric acid ammonium salt is washed once with petroleum ether.
[0012] Preferably, the thermally isomerized rosin is prepared by distilling a small amount of water contained in rosin containing isopimaric acid under 1 atmosphere and 90-114° C., distilling turpentine under 10-50 kPa and 140-170° C., and then heating to 150-180° C. for isomerization reaction for 1-3 hours, filtering, and cooling to room temperature.
[0013] Preferably, the rosin containing isopimaric acid is any one of slash pine rosin, Caribbean pine rosin, Simiao pine rosin and Masson pine rosin, and the best choice is slash pine rosin.
[0014] Preferably, the rosin may be gum rosin, tall oil rosin or wood rosin.
[0015] Preferably, the gum rosin is any one of slash pine rosin, Caribbean pine rosin, Simao pine rosin, and Masson pine rosin, and the best choice is slash pine rosin.
[0016] The present invention provides a method for preparing isopimaric acid by improving the method, which has the following improvements and advantages compared with the prior art:
[0017] 1. After turpentine distillation and rosin thermal isomerization, most of the levorotatory pimaric acid isomerized to abietic resin acid. Since both levorotatory pimaric acid and isopimaric acid can react with isobutanolamine or piperidine, only isopimaric acid is retained after thermal isomerization. The yield of the reaction is increased, and the yield of the method of the present invention can reach 10.1% relative to that of thermally isomerized rosin.
[0018] 2. The isopimaric acid ammonium salt uses ethanol, ethyl acetate, methyl tert-butyl ether and methanol with a volume fraction of 95% as solvent, and is washed once, pulped once, and recrystallized four times. This operation process can effectively remove other resin acids, especially abietic acid, contained in the isopimaric acid ammonium salt, thereby minimizing the interference of other resin acids and the loss of isopimaric acid ammonium salt, and improving the purity of isopimaric acid, which can reach 96%.
[0019] 3. Compared with the piperidine method, the crystallization speed of isopimaric acid by isobutanolamine is faster than that by piperidine, which greatly saves separation time and organic amines; compared with the maleic anhydride addition-isobutanolamine precipitation method, the method directly separates pimaric acid from rosin, reduces the loss in the intermediate steps, improves the yield of isopimaric acid, and simplifies the operation steps; compared with the distillation method, the operation conditions are simple and the yield is also higher. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0021] Figure 1 It is an operation flow chart of the double recrystallization method in the present invention.
[0022] Figure 2 This is the mass spectrometry analysis spectrum of the product methyl isopimarate.
[0023] Figure 3 This is the infrared spectrum analysis spectrum of the product isopimaric acid.
[0024] Figure 4 This is the proton nuclear magnetic resonance analysis spectrum of the product isopimaric acid. DETAILED DESCRIPTION
[0025] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.
[0026] The components of the embodiments of the present invention generally described and shown in the drawings herein may be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.
[0027] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.
[0028] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.
[0029] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0030] Example 1
[0031] A method for preparing isopimaric acid comprises the following steps:
[0032] S1: Dissolve the thermal isomerized rosin in acetone of 1 to 10 times the mass, add an acetone solution of isobutanolamine equivalent to 1 to 40% of the mass of the thermal isomerized rosin, acetone / isobutanolamine = 1:1 mL / g, form a precipitate, let stand, filter, wash with 50% ethanol by volume, and dry to obtain crude isopimaric acid ammonium salt; the crude isopimaric acid ammonium salt adopts a compound recrystallization method, a washing method and a pulping method, each group of isopimaric acid ammonium salt is first washed once, pulped and dried once, and then recrystallized and dried four times to obtain purified isopimaric acid ammonium salt crystals; the solvents used in the compound recrystallization method are ethanol, ethyl acetate, and methanol with a volume fraction of 95%, and the pulping solvent volume ratio is ethyl acetate: methyl tert-butyl ether: ethanol = 5:5:1. The isopimaric acid ammonium salt is washed once with petroleum ether. The amount of acetone used can be 1, 3 or 10 times the mass of the thermal isomerized rosin. The amount of isobutanolamine added can be 1%, 22% or 40% of the mass of the thermally isomerized rosin;
[0033] S2: Dissolve the purified ammonium isopimaric acid crystals obtained in the first step in 1 to 20 times the mass of n-hexane, add hydrochloric acid with a mass fraction of 1 to 20% in portions until the ammonium isopimaric acid crystals disappear, separate the water layer, wash the n-hexane layer with water until neutral, evaporate the n-hexane at 65 to 85°C under one atmosphere, dissolve the residue in 0.5 to 5 times the mass of acetone, slowly drip water into the solution until the precipitated crystals no longer increase, filter and dry to obtain purified isopimaric acid. The amount of n-hexane can be 1, 11 or 20 times the mass of ammonium isopimaric acid. The concentration of hydrochloric acid can be 1%, 10% or 20% by mass;
[0034] The operation process of the double recrystallization method is as follows Figure 1 As shown in the figure, C represents crystallization, A represents the "useful mother liquor" remaining after filtering the crystallization and to be combined for the next crystallization process, and the mother liquor represents the part that will be discarded and no longer used. The obtained crude ammonium salt of isopimaric acid is dissolved in an organic solvent, the crystals obtained from the first crystallization are C1, and the mother liquor is A1. A1 is concentrated to 1 / 2 of the volume to obtain crystals D1, and the mother liquor is discarded. C1 is dissolved again and recrystallized to obtain crystals C2, and the mother liquor is A2. Crystal D1 is dissolved in A2 and concentrated to 1 / 2 of the volume, and then crystallized to obtain crystal D2, and the mother liquor is discarded. Crystal C2 is dissolved and recrystallized to obtain crystals C3, and the mother liquor is A3. Crystal D2 is dissolved in A3 and the solution is concentrated to 1 / 2 of the volume, and then crystallized to obtain crystal D3, and the mother liquor is discarded. Crystal C3 is dissolved and recrystallized to obtain crystal C4 and mother liquor AS. Crystal D3 is dissolved in A4 and the solution is concentrated to 1 / 2 of the volume to obtain crystal D4, and the mother liquor is discarded. Crystal C4 is dissolved and recrystallized to obtain crystal C5 and mother liquor A5. The solution of crystal D4 in AS is concentrated to 1 / 2 of the volume to obtain crystal D5, and the mother liquor is discarded. C5 and D5 were combined and collected to obtain purified isopimaric acid ammonium salt.
[0035] The pulping process uses ethyl acetate, methyl tert-butyl ether and ethanol to dissolve and stir in a certain proportion, and then filter to obtain a filter cake. In the washing process, petroleum ether is used to wash the ammonium isopimaric acid salt, and filter to obtain a filter cake.
[0036] Example 2
[0037] 600 g of slash pine resin was put into a 1L four-necked flask, and a thermometer, a distillation head, a three-pronged tail pipe, and a receiving bottle were installed. Nitrogen was passed through the slash pine resin. A small amount of water contained in the slash pine resin was evaporated under 1 atmosphere and 90-114°C. Turpentine was evaporated under 10-50 kPa and 140-170°C. The temperature was then raised to 150-180°C for isomerization reaction for 1-3 hours. The flask was filtered and cooled to room temperature to obtain 478 g of thermal isomerized rosin. A sample was taken and subjected to methyl esterification treatment and then GC analysis. The mass fraction of isopimaric acid in the thermal isomerized rosin was 23.75%.
[0038] Example 3
[0039] The slash pine resin in Example 2 was replaced with Caribbean pine resin, and the rest remained unchanged.
[0040] Example 4
[0041] The elliott pine resin in Example 2 was replaced with pine resin, and the rest remained unchanged.
[0042] Example 5
[0043] The elliott pine resin in Example 2 was replaced with masson pine resin, and the rest remained unchanged.
[0044] Example 6
[0045] 200g of gum rosin, which may be any one of slash pine rosin, Caribbean rosin, Simiao pine rosin and Masson pine rosin, isomerize at 150-180℃ for 1-3h, filter and cool to room temperature to obtain thermal isomerized rosin.
[0046] Example 7
[0047] Take 200g of the thermal isomerized rosin obtained in Example 2 above and dissolve it in 1 times the mass of acetone, add an acetone solution of 15% isobutanolamine equivalent to the mass of the thermal isomerized rosin, isobutanolamine / acetone=1:1, g / mL, form a precipitate, let stand for 2h, filter, wash three times with 50% volume fraction of ethanol, dry, and obtain crude isopimaric acid ammonium salt; each group of isopimaric acid ammonium salt first completes 1 washing, 1 beating and drying, and then completes 4 recrystallizations and drying to obtain purified isopimaric acid ammonium salt crystals; the beating volume ratio of each time is ethyl acetate: methyl tert-butyl ether: ethanol: 5:5:1, stir at room temperature for more than 0.5h, filter and dry. During recrystallization, add 1 to 3 times the volume fraction of 95% ethanol when dissolving isopimaric acid ammonium salt, wash with 50% volume fraction of ethanol when filtering crystals, dry, and obtain 25.7g of purified isopimaric acid ammonium salt crystals.
[0048] The purified ammonium isopimaric acid salt was completely dissolved in 1 times the mass of n-hexane, and a 1% by mass aqueous solution of hydrochloric acid was added in portions until the ammonium isopimaric acid salt crystals disappeared, the water layer was separated, the n-hexane layer was washed with water until neutral, the n-hexane was evaporated at 65° C. under 1 atmosphere, the residue was dissolved in 0.5 times the mass of acetone, water was slowly dripped into the solution until the precipitated crystals no longer increased, filtered and dried to obtain 20.1 g of purified isopimaric acid, and the yield relative to the thermal isomerized rosin was 10.1%.
[0049] Example 8
[0050] Take 200g of the thermal isomerized rosin obtained in Example 2 above and dissolve it in 11 times the mass of acetone, add an acetone solution of 21% isobutanolamine equivalent to the mass of the thermal isomerized rosin, isobutanolamine / acetone=1:1, g / mL, form a precipitate, let stand for 2h, filter, wash three times with 50% ethanol by volume, dry, and obtain crude isopimaric acid ammonium salt; each group of isopimaric acid ammonium salt first completes 1 washing, 1 beating and drying, and then completes 4 recrystallizations and drying to obtain purified isopimaric acid ammonium salt crystals; the beating volume ratio of each time is ethyl acetate: methyl tert-butyl ether: ethanol: 5:5:1, stir at room temperature for more than 0.5h, filter and dry. During recrystallization, add 2 times the volume fraction of 95% ethanol when dissolving isopimaric acid ammonium salt, wash with 50% ethanol by volume when filtering and crystallizing, and dry to obtain purified isopimaric acid ammonium salt crystals.
[0051] The purified ammonium isopimaric acid salt is completely dissolved in 11 times the mass of n-hexane, and a 11% mass fraction of hydrochloric acid aqueous solution is added in portions until the ammonium isopimaric acid salt crystals disappear, the water layer is separated, the n-hexane layer is washed with water until neutral, the n-hexane is evaporated at 75° C. under 1 atmosphere, the residue is dissolved in 3.5 times the mass of acetone, water is slowly dripped into the solution until the precipitated crystals no longer increase, and the purified isopimaric acid is obtained by filtering and drying.
[0052] Example 9
[0053] Take 200g of the thermal isomerized rosin obtained in Example 2 above and dissolve it in 10 times the mass of acetone, add an acetone solution of 40% isobutanolamine equivalent to the mass of the thermal isomerized rosin, isobutanolamine / acetone=1:1, g / mL, form a precipitate, let stand for 2h, filter, wash three times with 50% volume fraction ethanol, dry, and obtain crude isopimaric acid ammonium salt; each group of isopimaric acid ammonium salt first completes 1 washing, 1 beating and drying, and then completes 4 recrystallizations and drying to obtain purified isopimaric acid ammonium salt crystals; the beating volume ratio of each time is ethyl acetate: methyl tert-butyl ether: ethanol: 5:5:1, stir at room temperature for more than 0.5h, then filter and dry. During recrystallization, add 1 to 3 times the volume fraction of 95% ethanol when dissolving isopimaric acid ammonium salt, wash with 50% volume fraction ethanol when filtering crystals, and dry to obtain purified isopimaric acid ammonium salt crystals.
[0054] The purified ammonium isopimaric acid salt is completely dissolved in 20 times the mass of n-hexane, and a 20% mass fraction of hydrochloric acid aqueous solution is added in portions until the ammonium isopimaric acid salt crystals disappear, the water layer is separated, the n-hexane layer is washed with water until neutral, the n-hexane is evaporated at 85° C. under 1 atmosphere, the residue is dissolved in 5 times the mass of acetone, water is slowly dripped into the solution until the precipitated crystals no longer increase, and the purified isopimaric acid is obtained by filtering and drying.
[0055] Example 10
[0056] Take 200g of the thermal isomerized rosin obtained in Example 6 above and dissolve it in 1 times the mass of acetone, add an acetone solution of 12% isobutanolamine equivalent to the mass of the thermal isomerized rosin, isobutanolamine / acetone=1:1, g / mL, form a precipitate, let stand for 2h, filter, wash three times with 50% volume fraction of ethanol, dry, and obtain crude isopimaric acid ammonium salt. Each group of isopimaric acid ammonium salt first completes 1 washing, 1 beating and drying, and then completes 4 recrystallizations and drying to obtain purified isopimaric acid ammonium salt crystals. The volume ratio of each beating is ethyl acetate: methyl tert-butyl ether: ethanol: 5:5:1, stir at room temperature for more than 0.5h, filter and dry. During recrystallization, add 1 to 3 times the volume fraction of 95% ethanol when dissolving isopimaric acid ammonium salt, wash with 50% volume fraction of ethanol when filtering crystals, and dry to obtain 24.8g of purified isopimaric acid ammonium salt crystals.
[0057] The purified ammonium isopimaric acid salt was completely dissolved in 1 times the mass of n-hexane, and a 1% by mass aqueous solution of hydrochloric acid was added in portions until the ammonium isopimaric acid salt crystals disappeared, the water layer was separated, the n-hexane layer was washed with water until neutral, the n-hexane was evaporated at 65° C. under 1 atmosphere, the residue was dissolved in 0.5 times the mass of acetone, water was slowly dripped into the solution until the precipitated crystals no longer increased, filtered and dried to obtain 19.8 g of purified isopimaric acid, and the yield relative to thermal isomerized rosin was 9.9%.
[0058] Embodiment 11
[0059] The product isopimaric acid obtained in Example 7 and Example 10 has a melting point of 162-164°C and a specific rotation of The temperature was 0° (the solvent was 95% ethanol, with a mass fraction of 2%), and the mass fraction of isopimaric acid in the product was measured by gas chromatography to be 96.7%.
[0060] HR-MS: The measured value of [MH] ion peak mass is 301.2174, the calculated value of [CJH20,] is 301.2168, A=0.66ppm. The measured value of molecular mass is 302.2248, given the molecular formula CuHsnO2 (DBE=6), the calculated value is 302.2246.
[0061] MS (see attached Figure 2 ), m / z (peak intensity, %): 3160M"; molecular ion peak of methyl isopimaric acid, CxH2O3, 35.5), 301 (M-Me, 21), 287 (M-(CH, -CH+H), 20), 2570M-Me-CO, 59.7), 256 (M-CO, Me, 50.7), 242 (25.3), 241 (100, M-Me-HCO.CH), 227 (20), 187 (30.2), 119 (26.3), 121 (25.8), 105 (30.3), 91 (25.7). The detection results of the mass spectrum database are consistent with the standard spectrum of isopimaric acid. IR (KBr tablet method, spectrum see attached Figure 3 ), v (cm'): 3432 (medium strong, broad peak, OH), 3079 (C=CH), .2940 (CH), 2656, 2528, 1694 (strong, C=0), 1463, 1387 (CH), 1277 (C-0), 1190, 906 (C=CH), 58.
[0062] 'HMIR (see attached Figure 4, CDC1;), δ (ppm): 0.8620 (s, 3H, C.-CH), 0.9068 (s, 3H, C.-CH), 1.2673 (s, 3H, C-CH), 1.0 85~1.146(m,1H), 1.3216-1.4138(m,2H)1.4716~1.4891(m,1H), 1.5250-1.5800(m,3H), 4.8651(dd,1H,-10.70Hz,5-1.25Hz,CH), 4.9251(dd,1H,5*17.50Hz,5=1.25Hz,CH), 5.3 22(dd,J=7.45Hz,1H,C=CH), 5.801(dd,1H,.-10.70Hz,J=17.50Hz,CH), 11.6~12.2(broad s,1H,COOH).
[0063] The chemical structure of isopimaric acid was accurately identified through the analysis results of the product's physical properties and mass spectrometry, infrared spectrum, and proton nuclear magnetic resonance spectrum.
[0064] Comparative Example 1
[0065] Dissolve 200g of slash pine rosin in 400mL of n-heptane, add 15g of piperidine, stir, cool the solution to room temperature, put it in a refrigerator and freeze it for 2h, stir continuously when the solution returns to room temperature, and then put the mixture in a refrigerator and freeze it overnight to precipitate ammonium salt. Use 95% ethanol as solvent, recrystallize isopimaric acid ammonium salt 5 times according to the double recrystallization method to obtain 25g of ammonium salt.
[0066] Dissolve the ammonium salt in 100 mL of n-hexane, add 1-20% hydrochloric acid until the crystals of isopimaric acid ammonium salt disappear. Separate the water layer, wash the n-hexane layer with water until it is neutral, evaporate the n-hexane at 65-85°C under one atmosphere, dissolve the residue in 0.5-5 times the mass of acetone, slowly drip distilled water into the solution until the precipitated crystals no longer increase, filter, dry to obtain 8.2 g of pure isopimaric acid, the yield is 4.1%, and the purity of isopimaric acid measured by gas chromatography is 87%.
[0067] Example 12
[0068] According to the method of Example 2, isobutanolamine was replaced by piperidine. Theoretical amounts of isobutanolamine and piperidine were added to equal amounts of rosin, respectively. When isobutanolamine was used, acetone was used as the recrystallization solvent, while when piperidine was used, n-heptane was used as the recrystallization solvent. The results are shown in Table 1
[0069] Table 1 Comparison of separation and purification effects between isobutanolamine method and piperidine method
[0070] project Isobutanolamine method Piperidine method Thermal isomerized rosin(g) 200 200 Amount of organic amine added (g) 14 15 Reaction time (h) 2 2 Isopimaric acid product (g) 20.1 8.2 Product yield (%) 10.1 4.1 Product purity (%) 96.7 87.0
[0071] Embodiment 13
[0072] According to the method of Example 2, the crude product of isopimaric acid ammonium salt was recrystallized by 95% ethanol in double recrystallization, and then the solvents were replaced by 95% ethanol, methyl acetate, methyl acetate-anhydrous ethanol (2:3, V / V), anhydrous ethanol, and methanol for three recrystallizations, and the purified isopimaric acid was obtained by the same treatment as in Example 1. The comparison of the recrystallization effects when using different recrystallization solvents is shown in Table 2
[0073] Table 2 Comparison of the effects of different recrystallization solvents
[0074]
[0075] Note: The yield of isopimaric acid is the mass fraction calculated relative to thermal isomerized rosin.
[0076] The above description enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for preparing isopimaric acid, characterized in that: The following steps are involved: S1: Dissolve the thermal isomerized rosin made of any one of rosin and rosin containing isopimaric acid in 1-10 times the mass of acetone, add dropwise an acetone solution of isobutanolamine equivalent to 1-40% of the mass of the thermal isomerized rosin, acetone / isobutanolamine=1:1mL / g, form a precipitate, let stand, filter, wash with 50% by volume ethanol, and dry to obtain a crude isopimaric acid ammonium salt; the crude isopimaric acid ammonium salt is prepared by a compound recrystallization method, a washing method, and a beating method, wherein each group of isopimaric acid ammonium salt is first washed once, beaten and dried once, and then recrystallized and dried four times to obtain purified isopimaric acid ammonium salt crystals; S2: dissolving the purified isopimaric acid ammonium salt crystals obtained in S1 in 1 to 20 times the mass of n-hexane, adding hydrochloric acid with a mass fraction of 1 to 20% in portions until the isopimaric acid ammonium salt crystals disappear, separating the water layer, washing the n-hexane layer with water until neutral, distilling off the n-hexane at 65 to 85° C. under one atmosphere, dissolving the residue in 0.5 to 5 times the mass of acetone, slowly dripping water into the solution until the precipitated crystals no longer increase, filtering and drying to obtain purified isopimaric acid.
2. A method for preparing isopimaric acid as claimed in claim 1, characterized in that: The solvents used in the double recrystallization method are ethanol, ethyl acetate and methanol with a volume fraction of 95%; the volume ratio of the pulping solvent is ethyl acetate: methyl tert-butyl ether: ethanol = 5:5:1, and the isopimaric acid ammonium salt is washed once with petroleum ether.
3. A method for preparing isopimaric acid as claimed in claim 1, characterized in that: The thermal isomerized rosin is prepared by distilling a small amount of water contained in rosin containing isopimaric acid under 1 atmosphere and 90-114° C., distilling turpentine under 10-50 kPa and 140-170° C., heating to 150-180° C. for isomerization reaction for 1-3 hours, filtering, and cooling to room temperature.
4. A method for preparing isopimaric acid as claimed in claim 1, characterized in that: The rosin containing isopimaric acid is any one of slash pine rosin, Caribbean pine rosin, Simiao pine rosin and Masson pine rosin.
5. A method for preparing isopimaric acid as claimed in claim 1, characterized in that: Rosin may be gum rosin, tall oil rosin or wood rosin.
6. A method for preparing isopimaric acid as claimed in claim 5, characterized in that: The gum rosin is any one of slash pine rosin, Caribbean pine rosin, Simao pine rosin and Masson pine rosin.