Method for preparing gamma, delta-unsaturated ketone by using organic acid-nitrogenous alkali composite catalytic system

Abstract

The invention discloses a method for preparing gamma, delta-unsaturated ketone by using an organic acid-nitrogenous alkali composite catalytic system. The invention provides a preparation method of a compound as shown in a formula I. The preparation method comprises the following step: reacting a compound as shown in a formula II with a compound as shown in a formula III to generate the compound as shown in the formula I under the action of organic acid and nitrogen-containing alkali. The preparation method provided by the invention can effectively inhibit the generation of conjugated diene by-products by dehydration, and significantly improve the selectivity and yield of target products.

Description

Technical Field

[0001] This invention relates to a method for preparing γ,δ-unsaturated ketones using an organic acid-nitrogen-containing base composite catalytic system. Background Technology

[0002] γ,δ-unsaturated ketones are an important class of fragrance and pharmaceutical intermediates, widely used in the synthesis of vitamins A, E, K1, carotenoids, ionones, and various fragrance compounds. Industrially, they are usually produced using the Saucy-Marbet reaction, in which tertiary allyl alcohols, such as 2-methyl-3-buten-2-ol (methylbutenol), linalool, dihydrolinalool (3,7-dimethyl-1-octen-3-ol), nerolidol, and dihydronerolidol (3,7,11-trimethyl-6-dodecyl-3-ol), undergo a C–C bond elongation reaction with alkoxyalkenyl ethers under the action of an acidic catalyst to generate the target ketone product.

[0003] However, existing technologies have significant drawbacks:

[0004] Traditional strong acid catalytic systems (such as phosphoric acid, sulfonic acid, Lewis acid, etc.) can promote the main reaction, but they also strongly catalyze the dehydration side reaction of tertiary allyl alcohols. This side reaction produces conjugated dienes, such as isoprene, ocimene, dihydroocimene (3,7-dimethyl-1,3-octadiene), farnesene, and dihydrofarnesene (3,7,11-trimethyl-1,3,6-dodecanetriene). These conjugated structures themselves have greater stability, exacerbating the acid-catalyzed dehydration tendency and severely reducing the selectivity of the target product. For low molecular weight tertiary alcohols (such as 2-methyl-3-buten-2-ol), the dehydration product is isoprene, which has a relatively low boiling point (34°C) and can be removed by venting or simple distillation, with a relatively controllable impact on the system. However, for high-carbon tertiary alcohols (such as linalool, dihydrolinalool, nerolidol, and dihydronerolidol), their dehydration products are high-boiling-point conjugated olefins (such as ocimene with a boiling point of about 178°C, and farnesene and dihydrofarnesene with boiling points >200°C), which are close to the boiling points of the target ketone products (such as dihydrogeranylacetone with a boiling point of about 120–130°C / 0.1 mmHg). They are difficult to separate effectively by conventional distillation and require complex and energy-intensive precision distillation, which significantly increases production costs and reduces yield.

[0005] CN1228757A (BASF) discloses a method for preparing γ,δ-unsaturated ketones from tertiary allyl alcohol and MOP under the catalysis of phosphorus-containing aryloxy derivatives. Although this method improves the reaction selectivity, it still does not fundamentally solve the dehydration problem of high carbon number tertiary alcohols. DE1193490 also uses a phosphoric acid catalytic system, but the reaction takes a long time, and increasing the temperature or the amount of catalyst will lead to increased side reactions and decreased yield.

[0006] CN 114907195 A (DSM) proposed using a complex of SO3 and organic amines to catalyze the reaction of tert-allyl alcohol with MOP. Although the addition of organic amines reduced the acidity, the acidity was still too strong. In examples applied to tert-allyl alcohols, the selectivity and conversion rates were only 40-50%.

[0007] CN102197014B (DSM) proposed using ammonium salts as catalysts to replace strong acids. Although this can improve selectivity to 90%, it does not involve subsequent distillation to obtain the product. The yield of pure product obtained by distillation will not be higher than 90%. In addition, the ammonium salts used are in solid form in the reaction system, which affects the convenience of feeding and is not conducive to continuous production.

[0008] In summary, tertiary allyl alcohols (such as methylbutenol, linalool, dihydrolinalool, nerolidol, and dihydronerolidol) readily undergo elimination dehydration when reacting with MOP under acidic conditions, generating conjugated diene byproducts. Since the boiling points of the corresponding dehydrated products are close to those of the target ketone products, they are difficult to separate by conventional distillation and require additional rectification operations, which significantly increases energy consumption. Therefore, there is an urgent need for reaction conditions that can improve the conversion rate and significantly inhibit the elimination of tertiary allyl alcohol structures. Summary of the Invention

[0009] The technical problem this invention aims to solve is to overcome the shortcomings of existing technologies in the preparation of γ,δ-unsaturated ketones, where the tert-allyl structure easily undergoes dehydration side reactions, leading to reduced yields and increased energy consumption in the main reaction. This invention provides a method for preparing γ,δ-unsaturated ketones using an organic acid-nitrogen-containing base composite catalytic system. The preparation method provided by this invention effectively suppresses the formation of conjugated diene byproducts during dehydration, significantly improving the selectivity and yield of the target product.

[0010] The present invention solves the above-mentioned technical problems through the following technical solutions.

[0011] The present invention provides a method for preparing a compound as shown in Formula I, comprising the following steps: under the action of an organic acid and a nitrogen-containing base, a compound as shown in Formula II reacts with a compound as shown in Formula III to generate a compound as shown in Formula I;

[0012] ;

[0013] in,

[0014] R1 is a C1-C6 alkyl group or a C6-C6 alkyl group. 12 alkenyl;

[0015] R2 is H or a C1-C4 alkyl group;

[0016] R3 is a C1-C4 alkyl group;

[0017] The pKa of the organic acid is 0.5-3.

[0018] In some embodiments of the present invention, the C1-C6 alkyl group is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, or... Preferably methyl or .

[0019] In some embodiments of the present invention, the C6-C 12 alkenyl is or .

[0020] In some embodiments of the present invention, each of the C1-C4 alkyl groups is methyl or ethyl.

[0021] In some embodiments of the present invention, the compound shown in Formula II is selected from one or more of 2-methyl-3-buten-2-ol, linalool, dihydrolinalool (3,7-dimethyl-1-octen-3-ol), nerolidol, and dihydronerolidol (3,7,11-trimethyl-6-undecene-3-ol); for example, 2-methyl-3-buten-2-ol, linalool, dihydrolinalool, or dihydronerolidol.

[0022] In some embodiments of the present invention, the compound represented by Formula III is selected from one or more of 2-methoxypropylene (MOP), 2-ethoxypropylene (EOP), 2-methoxy-2-butene (MOB), and 2-ethoxy-2-butene (EOB); for example, 2-methoxypropylene or 2-ethoxypropylene.

[0023] In some embodiments of the present invention, the compound represented by Formula I is methylheptenone, dihydrogeranylacetone (6,10-dimethyl-9-undecadien-2-one), geranylacetone (6,10-dimethyl-5,9-undecadien-2-one), or dihydrofarnesylacetone (6,10,14-trimethyl-5,9-pentadecadien-2-one).

[0024] In some embodiments of the present invention, the pKa of the organic acid is 0.5-2.

[0025] In some embodiments of the present invention, the organic acid is selected from one or more of oxalic acid, malonic acid, maleic acid, fumaric acid, butynediic acid, phthalic acid, monomethyl phosphate, dimethyl phosphate, chloroacetic acid, dichloroacetic acid, and trichloroacetic acid, preferably oxalic acid, maleic acid, dichloroacetic acid, or trichloroacetic acid.

[0026] In some embodiments of the present invention, the nitrogen-containing base is selected from ammonia, hydroxylamine, hydrazine, and C3-C. 10 Aliphatic tertiary amines, C2-C 10One or more of alkyl alcoholamines and hexamethylenetetramine, for example, 20wt%-30wt% ammonia, triethylamine, tri-n-propylamine, tri-n-butylamine, diethanolamine, triethanolamine or hexamethylenetetramine, preferably 25wt% ammonia, triethylamine, tri-n-butylamine or triethanolamine.

[0027] In some embodiments of the present invention, the molar ratio of the compound shown in Formula III to the compound shown in Formula II is (1-5):1, preferably (1.5-3.5):1, for example 2:1.

[0028] In some embodiments of the invention, the molar ratio of the organic acid to the compound as shown in Formula II is (0.001-0.1):1, preferably (0.015-0.05):1, for example 0.025:1, 0.03:1 or 0.04:1.

[0029] In some embodiments of the present invention, the molar ratio of the nitrogen-containing base to the organic acid is (0.01-0.3):1, preferably (0.02-0.05):1, for example 0.02:1 or 0.03:1.

[0030] In some embodiments of the present invention, the reaction temperature is between 90°C and 180°C, preferably between 100°C and 130°C, for example, 115°C, 125°C or 120°C.

[0031] In some embodiments of the present invention, the post-treatment of the reaction is vacuum distillation.

[0032] In some embodiments of the present invention, the pressure of the vacuum distillation is (-0.09 MPa) - (-0.1 MPa), for example -0.095 MPa or -0.099 MPa.

[0033] In some embodiments of the present invention, the temperature of the vacuum distillation is 90°C-130°C.

[0034] In some embodiments of the present invention, the preparation method includes the following steps: mixing a compound as shown in Formula II, an organic acid, and a nitrogen-containing base, heating to 90°C-180°C, and adding a compound as shown in Formula III dropwise to react and generate a compound as shown in Formula I.

[0035] In this invention, "alkyl" refers to a straight-chain or branched alkyl group having a specified number of carbon atoms (e.g., C1-C6 or C1-C4). Alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, sec-butyl, n-pentyl, n-hexyl, etc.

[0036] In this invention, "alkenyl" refers to a group having a specified number of carbon atoms (e.g., C6-C). 12A straight-chain or branched, unsaturated monovalent hydrocarbon group having one or more (e.g., 1, 2, or 3) carbon-carbon sp groups. 2 Double bonds, for example or .

[0037] Without violating common sense in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0038] Unless otherwise specified, all reagents and raw materials used in this invention are commercially available.

[0039] The positive and progressive effects of this invention are as follows: the preparation method provided by this invention can effectively suppress the formation of conjugated diene byproducts during dehydration, and significantly improve the selectivity and yield of the target product. Detailed Implementation

[0040] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0041] Example 1: Synthesis of methylheptenone

[0042] 2-Methyl-3-buten-2-ol (100 g, 1.16 mol), oxalic acid (pKa=1.23) (2.6 g, 29 mmol), and 25wt% ammonia water (60 mg) were added to a 1 L reactor. The temperature was raised to 115°C, and MOP (167 g mmol, 2.32 mol) was added dropwise. After reacting for 12 h, the reaction was stopped. GC monitoring showed a conversion rate of 99.9%, methylheptenone of 99.2%, isoprene of 0.4%, and a selectivity of 99.3%. After recovering MOP and low-boiling components at -0.07 MPa and 60-90°C, 144.2 g of the component (methylheptenone) was collected at 90-95°C and -0.095 MPa, with a purity of 99.8% and a yield of 98.3%.

[0043] 1 H NMR (400 MHz, CDCl3) δ 5.05 (t, J = 8.4 Hz, 1H), 2.44 (t, J = 7.4Hz, 2H), 2.24 (q, J = 7.3 Hz, 2H), 2.12 (s, 3H), 1.67 (s, 3H), 1.61 (s, 3H). 13C NMR (100 MHz, CDCl3) δ 208.79, 132.68, 122.66, 43.71, 29.85, 25.61, 22.52,17.59.

[0044] Example 2: Synthesis of dihydrogeranylacetone (6,10-dimethyl-9-undecen-2-one)

[0045] Step 1:

[0046] 202 g (1.58 mol) of 6-methyl-2-heptanone and 200 g of tetrahydrofuran were added to a 2 L three-necked flask. After purging with nitrogen, the mixture was cooled to 0 °C, and 1 L of 2 mol / L vinyl magnesium chloride solution was added. The mixture was then heated to 30 °C and reacted for 3 hours. After distillation to recover 500 g of tetrahydrofuran, the reaction mixture was quenched in 2 kg of saturated ammonium chloride solution. The aqueous phase was extracted with 500 g of toluene. After recovering the solvent from the toluene phase under reduced pressure, the fraction collected at -0.097 MPa and 95-105 °C yielded 230 g of dihydrolinalool (3,7-dimethyl-1-octen-3-ol), with a purity of 99.5% and a yield of 93%.

[0047] 1 H NMR (400 MHz, CDCl3) δ 5.92 (dd, J = 17.4, 10.8 Hz, 1H), 5.20 (dd,J = 17.4, 1.3 Hz, 1H), 5.04 (dd, J = 17.4, 1.3 Hz, 1H), 1.61 – 1.46 (m, 3H), 1.41 (s, 1H), 1.35 – 1.29 (m, 2H), 1.28 (s, 3H), 1.20 – 1.13 (m, 2H), 0.87 (d, J = 6.6 Hz, 6H). 13 C NMR (100 MHz, CDCl3) δ 145.30, 111.44, 73.28, 42.61, 39.35, 27.90, 27.64, 22.58, 22.57, 21.65.

[0048] Step 2:

[0049] Dihydrolinalool (3,7-dimethyl-1-octen-3-ol) (200 g, 1.28 mol), maleic acid (pKa=1.83) (4.45 g, 38 mmol), and triethylamine (116 mg) were added to a 1 L reactor. The mixture was heated to 125°C, and MOP (180 g mmol, 2.50 mol) was added dropwise. After reacting for 15 h, the reaction was stopped. GC monitoring showed a conversion rate of 99.4%, dihydrogeranylacetone of 98.6%, and dihydroocimene of 0.2%, with a selectivity of 99.2%. After recovering MOP and low-boiling components at -0.07 MPa and 60-90°C, 243.4 g of the component at 100-105°C and 200 Pa was collected, with a purity of 99.4% and a yield of 97.3%.

[0050] 1 ¹H NMR (400 MHz, CDCl₃) (E / Z structures not separated) δ 5.06 (td, J = 7.1, 1.2 Hz, 1H), 2.47 – 2.42 (m, 2H), 2.30 – 2.21 (m, 2H), 2.13 (s, 3H), 2.02 – 1.90 (m, 2H), 1.66 – 1.60 (d, J = 1.2 Hz, 3H), 1.57 – 1.47 (m, 1H), 1.42 – 1.31 (m, 2H), 1.19 – 1.08 (m, 2H), 0.87 (d, J = 6.6 Hz, 3H), 0.87 – 0.84 (d, J = 6.6 Hz, 3H). 13 C NMR (100 MHz, CDCl3) δ 208.78, 208.71, 136.97, 136.75, 122.97,122.27, 44.01, 43.79, 39.83, 38.85, 38.58, 31.90, 29.88, 27.89, 27.85, 25.71,25.64, 23.32, 22.60, 22.59, 22.47, 22.26, 15.84.

[0051] Example 3: Synthesis of Geraniolacetone (6,10-dimethyl-5,9-undecadien-2-one)

[0052] Linalool (201 g, 1.29 mol), dichloroacetic acid (pKa=1.48) (6.65 g, 51.5 mmol), and triethanolamine (230.5 mg) were added to a 1 L reaction vessel. The temperature was raised to 120°C, and MOP (180 g mmol, 2.50 mol) was added dropwise. After reacting for 16 h, the reaction was stopped. GC monitoring showed a conversion rate of 99.7%, geranylacetone of 97.2%, ocimene of 0.8%, and a selectivity of 97.5%. After recovering MOP and low-boiling components at -0.07 MPa and 60–90 °C, 238.1 g of the component at 105–110 °C and -0.099 MPa was collected, with a purity of 99.1% and a yield of 95.1%. 1 ¹H NMR (400 MHz, CDCl₃) (E / Z structures not separated) δ 5.35 (t, 1H), 5.09 (t, 1H), 4.58 (dd, 2H), 2.10–2.05 (m, 4H), 2.05 (m, 7H), 1.71 (s, 3H), 1.68 (s, 3H), 1.60 (s, 3H).

[0053] Example 4: Synthesis of dihydrofarnesyacetone (6,10,14-trimethyl-5,9-pentadecadien-2-one)

[0054] Step 1:

[0055] 200 g of geraniol (1.03 mol) and 200 g of tetrahydrofuran were added to a 2 L three-necked flask. After purging with nitrogen, the mixture was cooled to 5 °C, and 700 mL of 2 mol / L vinyl magnesium chloride solution was added. The mixture was then heated to 30 °C and reacted for 3 hours. After distilling to recover 500 g of tetrahydrofuran, the reaction mixture was quenched in 2 kg of saturated ammonium chloride solution. The aqueous phase was extracted with 500 g of toluene. After recovering the solvent from the toluene phase under reduced pressure, the fraction collected at 200 Pa and 130-140 °C yielded 213.4 g of dihydronerol (3,7,11-trimethyl-6-undecene-3-ol), with a purity of 99.6% and a yield of 93%.

[0056] 1¹H NMR (400 MHz, CDCl₃) (E / Z structures not separated) δ 5.92 (ddd, J = 17.3, 10.8, 2.9 Hz, 1H), 5.22 (dd, J = 17.3, 1.2 Hz, 1H), 5.15 – 5.09 (m, 1H), 5.08 – 5.04 (m, 1H), 2.09 – 1.90 (m, 4H), 1.67 (d, J = 1.2 Hz, 1H), 1.63 – 1.48 (m, 6H), 1.41 – 1.31 (m, 2H), 1.28 (d, J = 1.0 Hz, 3H), 1.19 – 1.09 (m, 2H), 0.87 (d, J = 6.6 Hz, 3H), 0.87 – 0.85 (d, J = 6.6 Hz, 3H). 13 C NMR (100 MHz, CDCl3)δ 145.09, 145.07, 136.11, 135.96, 124.66, 123.94, 111.68, 111.64, 73.48,73.41, 42.40, 42.12, 39.90, 38.88, 38.63, 31.94, 27.87, 27.85, 27.83, 25.70,23.38, 22.70, 22.62, 22.51, 15.92.

[0057] Step 2:

[0058] Dihydroneratol (3,7,11-trimethyl-6-undecene-3-ol) (200 g, 0.907 mol), trichloroacetic acid (pKa=0.70) (6.0 g, 36 mmol), and 25wt% ammonia water (49 mg) were added to a 1 L reaction vessel. EOP (156 g, 1.814 mol) was added dropwise at 120°C. After 16 h of reaction, the reaction was stopped. GC monitoring showed a conversion rate of 97.9%, dihydrofarnesylacetone of 95.4%, and dihydrofarnesene of 1.3%, with a selectivity of 97.4%. After recovering MOP and low-boiling components at -0.07 MPa and 60–90 °C, 226.8 g of the component at 135–145 °C and 200 Pa was collected, with a purity of 99.2% and a yield of 93.8%.

[0059] 1¹H NMR (400 MHz, CDCl₃) (E / Z structures not separated) δ 5.09 – 5.06 (m, 2H), 2.48 – 2.41 (m, 2H), 2.26 (q, J = 7.2 Hz, 2H), 2.13 (s, 3H), 2.09 – 1.90 (m, 6H), 1.69 – 1.64 (m, 2H), 1.59 (m, 4H), 1.52 (m, 1H), 1.41 – 1.31 (m, 2H), 1.19 – 1.08 (m, 2H), 0.88 (d, J = 6.6 Hz, 3H), 0.88 – 0.86 (d, J = 6.6 Hz, 3H). 13 CNMR (100 MHz, CDCl3) δ 208.74, 208.64, 208.58, 136.55, 136.44, 136.38,136.37, 135.88, 135.66, 135.65, 135.40, 124.54, 123.81, 123.71, 123.36,123.29, 122.57, 122.52, 44.01, 43.77, 43.75, 39.97, 39.94, 39.90, 39.67,38.92, 38.89, 38.66, 38.61, 32.17, 31.97, 31.89, 29.91, 29.89, 29.87, 29.85, 27.92, 27.88, 26.49, 26.41, 26.27, 25.83, 25.76, 25.74, 25.72, 23.39, 23.36, 22.63, 22.48, 22.30, 15.96, 15.87.

[0060] Comparative Example 1:

[0061] Synthesis of methylheptenone (using a strong inorganic acid)

[0062] The operation was similar to that in Example 1, except that 2.83 g of sulfuric acid (pKa = -3.00) was used instead of oxalic acid. GC monitoring showed a 100% conversion rate, 18.1% for methyl heptenone, 73.1% for isoprene, and a selectivity of 18.1%. After recovering MOP and low-boiling components at -0.07 MPa and 60-90°C, 24.6 g of the component at 90-95°C and -0.095 MPa was collected, with a purity of 99.1% and a yield of 16.7%.

[0063] Comparative Example 2

[0064] Synthesis of methylheptenone (without adding nitrogenous base)

[0065] The operation was similar to that in Example 1, except that ammonia was not used. GC monitoring showed a reaction conversion rate of 99.9%, methylheptenone of 90.1%, isoprene of 6.8%, and a selectivity of 90.1%. After recovering MOP and low-boiling components at -0.07 MPa and 60-90°C, 129.7 g of the component at 90-95°C and -0.095 MPa was collected, with a purity of 99.1% and a yield of 87.7%.

[0066] Comparative Example 3

[0067] Synthesis of methylheptenone (using a non-nitrogenous base)

[0068] The operation was similar to that in Example 1, except that 160 mg of a methanol solution containing 30% wt sodium methoxide was used instead of ammonia. GC monitoring showed a reaction conversion rate of 99.9%, methylheptenone of 92.4%, isoprene of 3.7%, and a selectivity of 92.4%. After recovering MOP and low-boiling components at -0.07 MPa and 60-90 °C, 132.3 g of the component at 90-95 °C and -0.095 MPa was collected, with a content of 99.2% and a yield of 89.6%.

[0069] Comparative Example 4

[0070] Synthesis of methylheptenone (using organic acids with pKa not in the range of 0.5-3)

[0071] The operation was similar to that in Example 1, except that acetic acid (pKa=4.74) was used in a methanol solution of 30% wt sodium methoxide at 160 mg. The final GC monitoring showed a reaction conversion rate of 1.2%.

[0072] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A method for preparing a compound as shown in Formula I, characterized in that, It includes the following steps: under the action of an organic acid and a nitrogen-containing base, the compound shown in Formula II reacts with the compound shown in Formula III to generate the compound shown in Formula I; ； in, R1 is a C1-C6 alkyl group or a C6-C6 alkyl group. 12 alkenyl; R2 is H or a C1-C4 alkyl group; R3 is a C1-C4 alkyl group; The pKa of the organic acid is 0.5-3.

2. The preparation method according to claim 1, characterized in that, The preparation method satisfies one or more of the following conditions: (1) The C1-C6 alkyl group is methyl or ; (2) The C6-C 12 alkenyl is or ; (3) Each of the C1-C4 alkyl groups is methyl or ethyl.

3. The preparation method according to claim 1, characterized in that, The preparation method satisfies one or more of the following conditions: (1) The compound shown in Formula II is selected from one or more of 2-methyl-3-buten-2-ol, linalool, dihydrolinalool, nerolidol, and dihydronerolidol; (2) The compound shown in Formula III is selected from one or more of 2-methoxypropene, 2-ethoxypropene, 2-methoxy-2-butene, and 2-ethoxy-2-butene; (3) The compound shown in Formula I is methylheptenone, 6,10-dimethyl-9-undecen-2-one, 6,10-dimethyl-5,9-undecen-2-one or 6,10,14-trimethyl-5,9-pentadecadien-2-one. (4) The pKa of the organic acid is 0.5-2; (5) The organic acid is selected from one or more of oxalic acid, malonic acid, maleic acid, fumaric acid, butynediic acid, phthalic acid, monomethyl phosphate, dimethyl phosphate, chloroacetic acid, dichloroacetic acid and trichloroacetic acid; (6) The nitrogen-containing base is selected from ammonia, hydroxylamine, hydrazine, C3-C 10 Aliphatic tertiary amines, C2-C 10 One or more of alkylolamines and hexamethylenetetramine; (7) The post-treatment of the reaction is vacuum distillation.

4. The preparation method according to claim 3, characterized in that, The preparation method satisfies one or more of the following conditions: (1) The compound shown in Formula II is 2-methyl-3-buten-2-ol, linalool, dihydrolinalool or dihydroneryl alcohol; (2) The compound shown in Formula III is 2-methoxypropene or 2-ethoxypropene; (3) The organic acid is oxalic acid, maleic acid, dichloroacetic acid or trichloroacetic acid; (4) The nitrogen-containing base is 20wt%-30wt% ammonia, triethylamine, tri-n-propylamine, tri-n-butylamine, diethanolamine, triethanolamine or hexamethylenetetramine.

5. The preparation method according to claim 1, characterized in that, The preparation method satisfies one or more of the following conditions: (1) The molar ratio of the compound shown in Formula III to the compound shown in Formula II is (1-5):1; (2) The molar ratio of the organic acid to the compound shown in Formula II is (0.001-0.1):1; (3) The molar ratio of the nitrogen-containing base to the organic acid is (0.01-0.3):1; (4) The reaction temperature is 90℃-180℃; (5) The nitrogen-containing base is 25wt% ammonia, triethylamine, tri-n-butylamine or triethanolamine.

6. The preparation method according to claim 5, characterized in that, The preparation method satisfies one or more of the following conditions: (1) The molar ratio of the compound shown in Formula III to the compound shown in Formula II is (1.5-3.5):1; (2) The molar ratio of the organic acid to the compound shown in Formula II is (0.015-0.05):1; (3) The molar ratio of the nitrogen-containing base to the organic acid is (0.02-0.05):1; (4) The reaction temperature of the reaction is 100-130℃.

7. The preparation method according to claim 5, characterized in that, The preparation method satisfies one or more of the following conditions: (1) The molar ratio of the compound shown in Formula III to the compound shown in Formula II is 2:1; (2) The molar ratio of the organic acid to the compound shown in Formula II is 0.025:1, 0.03:1 or 0.04:1; (3) The molar ratio of the nitrogen-containing base to the organic acid is 0.02:1 or 0.03:1; (4) The reaction temperature is 115°C, 125°C or 120°C.

8. The preparation method according to claim 3, characterized in that, The preparation method satisfies one or two of the following conditions: (1) The pressure of the vacuum distillation is (-0.09MPa) - (-0.1MPa); (2) The temperature of the vacuum distillation is 90℃-130℃.

9. The preparation method according to claim 3, characterized in that, The pressure of the vacuum distillation is -0.095 MPa or -0.099 MPa.

10. The preparation method according to claim 1, characterized in that, The preparation method includes the following steps: mixing the compound shown in Formula II, an organic acid, and a nitrogen-containing base, heating to 90℃-180℃, and adding the compound shown in Formula III dropwise to react and generate the compound shown in Formula I.

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