A continuous saucy-marbet ketonization reaction process for allyl alcohol compounds

Abstract

The application discloses a continuous Saucy-Marbet ketonization reaction process of allyl alcohol compounds. Specifically provided is a preparation method of compound II, which comprises the following steps: reacting compound I and 2-methoxy propylene in the presence of an acid in a tubular reactor to generate compound II; and the acid is added in the following manner: in the first stage, the molar ratio of the acid to the compound I is 0.005-0.015; in the second stage, the molar ratio of the acid to the compound I is 0.006-0.020; and in the third stage, the molar ratio of the acid to the compound I is 0.009-0.025. The preparation method disclosed by the application has one or more of the following advantages: (1) high yield, (2) high purity, (3) few side reactions, (4) simple operation and (5) low cost.

Description

Technical Field

[0001] This invention relates to a continuous Saucy–Marbet ketation process for allyl alcohol compounds. Background Technology

[0002] The Saucy–Marbet ketation of allyl alcohols was first disclosed by Roman Marbet and Gabriel Saucy in patent US3029287 in 1962, and the process is a Claisen rearrangement derivatization reaction.

[0003] DE1193490 discloses a method for preparing γ,δ-unsaturated ketones by reacting allyl alcohol with enol ethers. This method specifically employs a 0.1-0.2% phosphoric acid catalyst, a temperature of 125-140℃, a pressure of 1 MPa, and a reaction time of 13-18 hours. The drawbacks of this method are its long reaction time, poor selectivity, the dehydration of the raw material to form conjugated dienes, a relatively high amount of isomerization impurities in the product, high pressure, and large equipment investment.

[0004] CN1228757A reports a method for preparing γ,δ-unsaturated ketones using organophosphate derivatives, especially esters, as catalysts. The reaction is carried out in a high-pressure reactor at 130-160°C for 7-9 hours, with a yield of 82%-93%. The yield does not show a significant advantage, and organophosphate derivatives are expensive and difficult to prepare, making them unsuitable as industrial catalysts.

[0005] CN108299171A discloses a method for synthesizing methylheptenone from 2-methyl-3-buten-2-ol, which involves a Saucy-Marbet reaction between 2-methyl-3-buten-2-ol and 2-alkoxypropene in a near-critical state, with a conversion rate exceeding 97%. This synthesis method operates at temperatures between 260-290℃ and pressures between 6-10 MPa. Such high temperatures and pressures require significant investment in equipment, and consequently, necessitate a higher level of safety in the reaction.

[0006] CN102197014B discloses a method for preparing γ,δ-unsaturated ketones via the Saucy-Marbet reaction, using 1-2% molar equivalents of inorganic ammonium salts such as ammonium bromide, ammonium chloride, and diammonium hydrogen phosphate as catalysts. The reaction is carried out in a high-pressure reactor at 120-160°C for 12 hours. However, these catalysts undergo some decomposition during the high-temperature catalytic process. The acidity of this decomposition leads to the dehydration of allyl alcohol and the polymerization of 2-methoxypropylene. Furthermore, the halide ions released during decomposition cause significant corrosion to equipment and can easily clog pipelines, thus posing certain risks.

[0007] Existing Saucy–Marbet ketation reaction technologies all have various defects, and further development and optimization of the reaction process are needed to achieve high selectivity and develop production processes with low unit consumption and low high-boiling residue generation. Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of existing technologies by providing a continuous Saucy-Marbet ketation process for allyl alcohol compounds. This process is achieved through a three-stage tubular plug flow reactor, using phosphorous acid or a combination of phosphorous acid and phosphoric acid as a catalyst. Appropriate amounts of acid catalyst are continuously added at suitable reaction stages to precisely achieve stable control of reaction kinetics, shorten reaction time, significantly improve reaction selectivity, reduce side reactions and the generation of high-boiling residues. This is a cost-effective and green process.

[0009] The present invention solves the above-mentioned technical problems through the following technical solutions.

[0010] The present invention provides a method for preparing compound II, which includes the following steps: in a tubular reactor, in the presence of acid, compound I and 2-methoxypropylene react to generate compound II;

[0011]

[0012] Among them, R 1 and R 2 Independently selected from hydrogen, C1-C 12 Alkyl and C2-C 12 alkenyl;

[0013] The acid is added in the following manner:

[0014] In the first stage, the molar ratio of the acid to compound I is 0.005-0.015 (the acid refers to the molar amount of acid added in the first stage; the compound I refers to the total molar amount of compound I added during the overall reaction).

[0015] In the second stage, the molar ratio of the acid to compound I is 0.006-0.020 (the acid refers to the molar amount of acid added in the second stage; the compound I refers to the total molar amount of compound I added during the overall reaction process);

[0016] In the third stage, the molar ratio of the acid to compound I is 0.009-0.025 (the acid refers to the molar amount of acid added in the third stage; the compound I refers to the total molar amount of compound I added during the overall reaction).

[0017] In the preparation method, the reactor can be a three-stage tubular plug flow reactor.

[0018] In the preparation method, the C1-C 12 The alkyl group is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, or... Preferably methyl or

[0019] In the preparation method, the C2-C 12 The alkenyl group is vinyl, propenyl, butenyl or Preferred

[0020] In the preparation method, compound I can be methylbutenol, dihydrolinalool, or dihydronerol.

[0021] In the preparation method, in the first stage, the molar ratio of the acid to compound I is preferably 0.005, 0.006, 0.008, 0.010, 0.012 or 0.013.

[0022] In the preparation method, during the second stage, the molar ratio of the acid to compound I is preferably 0.006, 0.009, 0.011, 0.012, 0.015, or 0.018.

[0023] In the preparation method, in the third stage, the molar ratio of the acid to compound I is preferably 0.009, 0.012, 0.014, 0.020 or 0.025.

[0024] In the preparation method, in the first stage, the volumetric flow rate ratio of the acid to compound I is 0.02-0.06, preferably 0.06, 0.05, 0.04, 0.03 or 0.02.

[0025] In the preparation method, during the second stage, the volumetric flow rate ratio of the acid to compound I is 0.02-0.10, preferably 0.10, 0.09, 0.07, 0.06, 0.05, 0.04, 0.03 or 0.02.

[0026] In the preparation method, in the third stage, the volumetric flow rate ratio of the acid to compound I is 0.03-0.11, preferably 0.11, 0.10, 0.06, 0.05, 0.04 or 0.03.

[0027] In the preparation method, the reaction temperature can be 90–120°C.

[0028] In the preparation method, the reaction temperature in the first stage can be 90-100℃.

[0029] In the preparation method, the reaction temperature in the second stage can be 100-110°C.

[0030] In the preparation method, the reaction temperature in the third stage can be 110–120°C.

[0031] In the preparation method, the acid can be a combination of phosphorous acid and phosphoric acid.

[0032] In the preparation method, the proportion of phosphoric acid in the combined acid can be 0% to 40%.

[0033] In the preparation method, the acid can be an acid solution soluble in methanol; the molar concentration of the acid solution can be 1.0 to 2.0 mmol / mL; preferably 1.1 mmol / mL, 1.2 mmol / mL, 1.3 mmol / mL or 1.9 mmol / mL.

[0034] In the preparation method, when compound I is methylbutenol, the proportion of phosphoric acid in the combined acid is preferably 0-10%; for example, 0%, 5% or 10%.

[0035] In the preparation method, when compound I is dihydrolinalool, the proportion of phosphoric acid in the combined acid is preferably 10%-20%; for example, 10%, 15% or 20%.

[0036] In the preparation method, when compound I is dihydroneretol, the proportion of phosphoric acid in the combined acid is preferably 20-30%; for example, 20%, 25% or 30%.

[0037] In the preparation method, the molar ratio of the acid to compound I can be 0.01 to 0.1 (the acid refers to the total amount of acid added during the overall reaction); preferably 0.01-0.05; more preferably 0.02, 0.03, 0.04 or 0.05.

[0038] In the preparation method, the flow rate of compound I can be 25-100 mL / min; preferably 50 mL / min.

[0039] In the preparation method, the total flow rate of the acid can be 3 to 15 mL / min; preferably 12.5 mL / min, 12.2 mL / min, 10.1 mL / min, 7.2 mL / min, 7.1 mL / min, 5.8 mL / min, 5.2 mL / min or 4.4 mL / min.

[0040] In the preparation method, the molar ratio of 2-methoxypropylene to compound I can be 2 to 5; preferably 3.

[0041] In the preparation method, the flow rate of 2-methoxypropylene can be 50-150 mL / min; preferably 56 mL / min, 79 mL / min or 139 mL / min.

[0042] In the preparation method, the pressure of the reactor is 0.3 to 2.0 MPa.

[0043] In the preparation method, the liquid holding volume of each section of the reactor can be 50-200 mL, preferably 100 mL.

[0044] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0045] The reagents and raw materials used in this invention are all commercially available.

[0046] The positive and progressive effects of this invention are as follows:

[0047] (1) This invention achieves stable and precise process control of the Saucy–Marbet ketation reaction, greatly reducing the high-boiling residual liquid that is easily generated during the dimerization or dehydration aggregation of raw materials under high temperature, strong acid and long residence time. The product yield is high, the purity is high and the side reactions are few.

[0048] (2) The present invention uses a catalyst to realize a multi-step reaction of continuous Saucy–Marbet ketation reaction, which is simple to operate;

[0049] (3) The present invention can significantly reduce the consumption of 2-methoxypropylene and allyl alcohol, and the cost is low. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the three-stage tubular plug flow reactor in this invention. Detailed Implementation

[0051] 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.

[0052] In this invention, a three-stage tubular plug flow reactor is used to screen and optimize the reaction conditions. A schematic diagram of the reactor is shown below. Figure 1 As shown, both materials and catalysts are pumped in via high-pressure feed pumps. Each reaction section (plate-type heart-shaped channel reactor) is equipped with an independent circulating constant-temperature heat exchange system, which can precisely control the temperature of the reaction system. The liquid holding volume of each tubular reactor section is 100 mL.

[0053] Example 1

[0054]

[0055] Prepare the phosphorous acid solution: Dissolve the phosphorous acid in 5 times its volume of methanol to prepare a molar concentration of 1.9 mmol / mL. The ratio of the total flow rate of the acid solution to the flow rate of methylbutenol is 0.25. The total acid flow rate for the three stages is 12.5 ml / min, and the molar equivalent is 0.05.

[0056] Methylbutenol (flow rate: 50 ml / min, 482 mmol), 2-methoxypropylene (flow rate: 139 ml / min, 1446 mmol), and methanolic phosphorite solution (flow rate: 3.1 mL / min, methylbutenol flow rate ratio 0.06, 25% of total acid content) were pumped into a single-stage tubular plug flow reactor, and the temperature was controlled at 90-100℃.

[0057] After the flow rate stabilized, a methanol solution of phosphorous acid (flow rate: 4.4 mL / min, flow rate ratio to methylbutenol: 0.09, 35% of the total acid content) was pumped into the 2-stage tubular plug flow reactor. The temperature was controlled at 100-110℃. After the flow rate stabilized, a methanol solution of phosphorous acid (flow rate: 5 mL / min, flow rate ratio to methylbutenol: 0.10, 40% of the total acid content) was pumped into the 3-stage tubular plug flow reactor. The temperature was controlled at 110-120℃. After the flow rate stabilized, the reaction liquid flowing out of the 3-stage tubular plug flow reactor was collected and the components were analyzed by gas chromatography: methylheptenone / methylbutenol = 97.3 / 0.2.

[0058] 1 L of material was collected and distilled to obtain a yield of 96.9% and a residue of 2.0%.

[0059] Example 2

[0060] Prepare a mixed solution of phosphoric acid and phosphoric acid: Dissolve the combined acid with a phosphoric acid molar ratio of 5% in 5 times the amount of methanol to prepare a molar concentration of 1.9 mmol / mL. The ratio of the total flow rate of the acid solution to the flow rate of methylbutenol is 0.20. The total acid flow rate of the three stages is 10.1 ml / min, and the molar equivalent is 0.04.

[0061] Methylbutenol (flow rate: 50 ml / min, 482 mmol), 2-methoxypropylene (flow rate: 139 ml / min, 1446 mmol), and combined acid methanol solution (flow rate: 2.0 mL / min, methylbutenol flow rate ratio 0.04, 20% of total acid content) were pumped into a single-stage tubular plug flow reactor, and the temperature was controlled at 90-100℃.

[0062] After the flow rate stabilized, a combined acid methanol solution (flow rate: 3.0 mL / min, methylbutenol flow rate ratio 0.06, 30% of the total acid) was pumped into the 2-stage tubular plug flow reactor, with the temperature controlled at 100-110℃. After the flow rate stabilized, a combined acid methanol solution (flow rate: 5.1 mL / min, methylbutenol flow rate ratio 0.10, 50% of the total acid) was pumped into the 3-stage tubular plug flow reactor, with the temperature controlled at 110-120℃. After the flow rate stabilized, the reaction liquid flowing out of the 3-stage tubular plug flow reactor was collected, and the components were analyzed by gas chromatography: methylheptenone / methylbutenol = 97.1 / 0.3.

[0063] 1 L of material was collected and distilled to obtain a yield of 96.6% and a residue of 2.2%.

[0064] Example 3

[0065] Prepare a mixed solution of phosphoric acid and phosphoric acid: Dissolve the combined acid with a phosphoric acid molar ratio of 10% in 8 times the amount of methanol to prepare a molar concentration of 1.2 mmol / mL. The ratio of the total flow rate of the acid solution to the flow rate of methylbutenol is 0.24. The total acid flow rate of the three stages is 12.2 ml / min, and the molar equivalent is 0.03.

[0066] Methylbutenol (flow rate: 50 ml / min, 482 mmol), 2-methoxypropylene (flow rate: 139 ml / min, 1446 mmol), and a combined acid methanol solution (flow rate: 2.4 mL / min, methylbutenol flow rate ratio 0.05, 20% of total acid content) were pumped into a single-stage tubular plug flow reactor, and the temperature was controlled at 90-100℃.

[0067] After the flow rate stabilized, a combined acid-methanol solution (flow rate: 4.3 mL / min, methylbutenol flow rate ratio 0.09, 35% of total acid) was pumped into the 2-stage tubular plug flow reactor, with the temperature controlled at 100-110℃. After the flow rate stabilized, a combined acid-methanol solution (flow rate: 5.5 mL / min, methylbutenol flow rate ratio 0.11, 45% of total acid) was pumped into the 3-stage tubular plug flow reactor, with the temperature controlled at 110-120℃. After the flow rate stabilized, the reaction liquid flowing out of the 3-stage tubular plug flow reactor was collected, and the components were analyzed by gas chromatography: methylheptenone / methylbutenol = 96.9 / 0.2.

[0068] 1 L of material was collected and distilled to obtain a yield of 96.3% and a residue of 2.5%.

[0069] The data from Examples 1-5 are summarized in Table 1 below: (Methylbutenol flow rate: 2-methoxypropylene flow rate = 50 mL / min: 139 mL / min) Preparation of methylheptenone;

[0070] Table 1(a)

[0071]

[0072] Table 1(b)

[0073]

[0074]

[0075] Comparative Example 1

[0076] Prepare phosphorous acid solution: Dissolve phosphorous acid in 5 times its volume of methanol to prepare a molar concentration of 1.9 mmol / mL. The ratio of the total flow rate of the acid solution to the flow rate of methylbutenol is 0.25, the total acid flow rate is 12.5 ml / min, and the molar equivalent is 0.05.

[0077] Methylbutenol (flow rate: 50 ml / min, 482 mmol), 2-methoxypropylene (flow rate: 139 ml / min, 1446 mmol), and methanolic phosphorous acid solution (flow rate: 12.5 mL / min, methylbutenol flow rate ratio 0.25, 100% of total acid content) were pumped into a single-stage tubular plug flow reactor, and the temperature was controlled at 90-100℃.

[0078] The temperature control for the 2-stage tubular plug flow reactor is 100-110℃, and the temperature control for the 3-stage tubular plug flow reactor is 110-120℃. The reaction liquid flowing out of the 3-stage tubular plug flow reactor is collected and the components are analyzed by gas chromatography: methyl heptenone / methyl butenol = 87.0 / 9.7.

[0079] 1 L of material was collected and distilled to obtain a yield of 85.3% and a residue of 5.9%.

[0080] Example 6

[0081]

[0082] Prepare a mixed solution of phosphoric acid and phosphoric acid: Dissolve the combined acid with a phosphoric acid molar ratio of 5% in 5 times the amount of methanol to prepare a molar concentration of 1.9 mmol / mL. The ratio of the total flow rate of the acid solution to the flow rate of dihydrolinalool is 0.14. The total acid flow rate of the three stages is 7.1 ml / min, and the molar equivalent is 0.05.

[0083] Dihydrolinalool (flow rate: 50 ml / min, 272 mmol), 2-methoxypropylene (flow rate: 79 ml / min, 816 mmol), and a combined acid methanol solution (flow rate: 1.8 mL / min, dihydrolinalool flow rate ratio 0.04, 25% of total acid content) were pumped into a single-stage tubular plug flow reactor, and the temperature was controlled at 90-100℃.

[0084] After the flow rate stabilized, a combined acid methanol solution (flow rate: 2.5 mL / min, flow rate ratio to dihydrolinalool 0.05, 35% of the total acid) was pumped into the 2-stage tubular plug flow reactor, with the temperature controlled at 100-110℃. After the flow rate stabilized, a combined acid methanol solution (flow rate: 2.9 mL / min, flow rate ratio to dihydrolinalool 0.06, 40% of the total acid) was pumped into the 3-stage tubular plug flow reactor, with the temperature controlled at 110-120℃. After the flow rate stabilized, the reaction liquid flowing out of the 3-stage tubular plug flow reactor was collected and the components were analyzed by gas chromatography: dihydrogeranylacetone / dihydrolinalool = 95.2 / 1.9.

[0085] 1 L of material was collected and distilled to obtain a yield of 93.3% and a residue of 2.6%.

[0086] Example 7

[0087] Prepare a mixed solution of phosphoric acid and phosphoric acid: Dissolve the combined acid with a phosphoric acid molar ratio of 10% in 5 times the amount of methanol to prepare a molar concentration of 1.9 mmol / mL. The ratio of the total flow rate of the acid solution to the flow rate of dihydrolinalool is 0.14. The total acid flow rate of the three stages is 7.2 ml / min, and the molar equivalent is 0.05.

[0088] Dihydrolinalool (flow rate: 50 ml / min, 272 mmol), 2-methoxypropylene (flow rate: 79 ml / min, 816 mmol), and a combined acid methanol solution (flow rate: 1.8 mL / min, dihydrolinalool flow rate ratio 0.04, 25% of total acid content) were pumped into a single-stage tubular plug flow reactor, and the temperature was controlled at 90-100℃.

[0089] After the flow rate stabilized, a combined acid methanol solution (flow rate: 2.5 mL / min, flow rate ratio to dihydrolinalool 0.05, 35% of the total acid) was pumped into the 2-stage tubular plug flow reactor, with the temperature controlled at 100-110℃. After the flow rate stabilized, a combined acid methanol solution (flow rate: 2.9 mL / min, flow rate ratio to dihydrolinalool 0.06, 40% of the total acid) was pumped into the 3-stage tubular plug flow reactor, with the temperature controlled at 110-120℃. After the flow rate stabilized, the reaction liquid flowing out of the 3-stage tubular plug flow reactor was collected, and the components were analyzed by gas chromatography: dihydrogeranylacetone / dihydrolinalool = 97.0 / 0.4.

[0090] 1 L of material was collected and distilled to obtain a yield of 96.6% and a residue of 2.5%.

[0091] Example 8

[0092] Prepare a mixed solution of phosphoric acid and phosphoric acid: Dissolve the combined acid with a phosphoric acid molar ratio of 15% in 5 times the amount of methanol to prepare a molar concentration of 1.9 mmol / mL. The ratio of the total flow rate of the acid solution to the flow rate of dihydrolinalool is 0.12. The total acid flow rate of the three stages is 5.8 ml / min, and the molar equivalent is 0.04.

[0093] Dihydrolinalool (flow rate: 50 ml / min, 272 mmol), 2-methoxypropylene (flow rate: 79 ml / min, 816 mmol), and a combined acid methanol solution (flow rate: 1.2 mL / min, dihydrolinalool flow rate ratio 0.02, 20% of total acid content) were pumped into a single-stage tubular plug flow reactor, and the temperature was controlled at 90-100℃.

[0094] After the flow rate stabilized, a combined acid methanol solution (flow rate: 1.7 mL / min, dihydrolinalool flow rate ratio 0.03, 30% of the total acid) was pumped into the 2-stage tubular plug flow reactor, with the temperature controlled at 100-110℃. After the flow rate stabilized, a combined acid methanol solution (flow rate: 2.9 mL / min, dihydrolinalool flow rate ratio 0.06, 50% of the total acid) was pumped into the 3-stage tubular plug flow reactor, with the temperature controlled at 110-120℃. After the flow rate stabilized, the reaction liquid flowing out of the 3-stage tubular plug flow reactor was collected, and the components were analyzed by gas chromatography: dihydrogeranylacetone / dihydrolinalool = 97.3 / 0.3.

[0095] 1 L of material was collected and distilled to obtain a yield of 96.5% and a residue of 2.7%.

[0096] The data from Examples 6-10 are summarized in Table 2 below: (Dihydrolinalool flow rate: 2-methoxypropylene flow rate = 50 mL / min: 79 mL / min) Preparation of dihydrogeranylacetone;

[0097] Table 2(a)

[0098]

[0099] Table 2(b)

[0100]

[0101] Comparative Example 2

[0102] Prepare a mixed solution of phosphoric acid and phosphoric acid: Dissolve the combined acid (phosphoric acid molar ratio of 5%) in 5 times the amount of methanol to prepare a molar concentration of 1.9 mmol / mL. The ratio of the total flow rate of the acid solution to the flow rate of dihydrolinalool is 0.14, the total acid flow rate is 7.1 ml / min, and the molar equivalent is 0.05.

[0103] Dihydrolinalool (flow rate: 50 ml / min, 272 mmol), 2-methoxypropylene (flow rate: 79 ml / min, 816 mmol), and a combined acid methanol solution (flow rate: 7.1 mL / min, dihydrolinalool flow rate ratio 0.14, 100% of total acid content) were pumped into a single-stage tubular plug flow reactor, and the temperature was controlled at 90-100℃.

[0104] The temperature of the two-stage tubular plug flow reactor was controlled at 100-110℃, and the temperature of the three-stage tubular plug flow reactor was controlled at 110-120℃. After the flow rate stabilized, the reaction liquid flowing out of the three-stage tubular plug flow reactor was collected and the components were analyzed by gas chromatography: dihydrogeranylacetone / dihydrolinalool = 90.0 / 8.9.

[0105] 1 L of material was collected and distilled to obtain a yield of 86.8% and a residue of 4.7%.

[0106] Example 11

[0107]

[0108] Prepare a mixed solution of phosphoric acid and phosphoric acid: Dissolve the combined acid with a phosphoric acid molar ratio of 15% in 5 times the amount of methanol to prepare a molar concentration of 1.9 mmol / mL. The ratio of the total flow rate of the acid solution to the flow rate of dihydroneretol is 0.10. The total acid flow rate of the three stages is 5.2 ml / min, and the molar equivalent is 0.05.

[0109] Dihydronerol (flow rate: 50 ml / min, 194 mmol), 2-methoxypropylene (flow rate: 56 ml / min, 582 mmol), and a combined acid methanol solution (flow rate: 1.3 mL / min, dihydronerol flow rate ratio 0.03, 25% of total acid content) were pumped into a single-stage tubular plug flow reactor, and the temperature was controlled at 90-100℃.

[0110] After the flow rate stabilized, a combined acid methanol solution (flow rate: 1.8 mL / min, flow rate ratio to dihydroneryl alcohol 0.04, 35% of the total acid) was pumped into the 2-stage tubular plug flow reactor, with the temperature controlled at 100-110℃. After the flow rate stabilized, a combined acid methanol solution (flow rate: 2.1 mL / min, flow rate ratio to dihydroneryl alcohol 0.04, 40% of the total acid) was pumped into the 3-stage tubular plug flow reactor, with the temperature controlled at 110-120℃. After the flow rate stabilized, the reaction liquid flowing out of the 3-stage tubular plug flow reactor was collected, and the components were analyzed by gas chromatography: dihydrofarnesylacetone / dihydroneryl alcohol = 96.1 / 1.7.

[0111] 1 L of material was collected and distilled to obtain a yield of 95.0% and a residue of 2.3%.

[0112] Example 12

[0113] Prepare a mixed solution of phosphoric acid and phosphoric acid: Dissolve the combined acid with a phosphoric acid molar ratio of 20% in 5 times the amount of methanol to prepare a molar concentration of 1.9 mmol / mL. The ratio of the total flow rate of the acid solution to the flow rate of dihydroneretol is 0.10. The total acid flow rate of the three stages is 5.2 ml / min, and the molar equivalent is 0.05.

[0114] Dihydronerol (flow rate: 50 ml / min, 194 mmol), 2-methoxypropylene (flow rate: 56 ml / min, 582 mmol), and a combined acid methanol solution (flow rate: 1.0 mL / min, dihydronerol flow rate ratio 0.02, 20% of total acid content) were pumped into a single-stage tubular plug flow reactor, and the temperature was controlled at 90-100℃.

[0115] After the flow rate stabilized, a combined acid methanol solution (flow rate: 1.6 mL / min, flow rate ratio to dihydroneryl alcohol 0.03, 30% of the total acid) was pumped into the 2-stage tubular plug flow reactor, with the temperature controlled at 100-110℃. After the flow rate stabilized, a combined acid methanol solution (flow rate: 2.6 mL / min, flow rate ratio to dihydroneryl alcohol 0.05, 50% of the total acid) was pumped into the 3-stage tubular plug flow reactor, with the temperature controlled at 110-120℃. After the flow rate stabilized, the reaction liquid flowing out of the 3-stage tubular plug flow reactor was collected, and the components were analyzed by gas chromatography: dihydrofarnesylacetone / dihydroneryl alcohol = 97.0 / 0.5.

[0116] 1 L of material was collected and distilled to obtain a yield of 96.0% and a residue of 2.7%.

[0117] Example 13

[0118] Prepare a mixed solution of phosphoric acid and phosphoric acid: Dissolve the combined acid with a phosphoric acid molar ratio of 25% in 7 times the amount of methanol to prepare a molar concentration of 1.3 mmol / mL. The ratio of the total flow rate of the acid solution to the flow rate of dihydroneretol is 0.09. The total acid flow rate of the three stages is 4.4 ml / min, and the molar equivalent is 0.03.

[0119] Dihydronerol (flow rate: 50 ml / min, 194 mmol), 2-methoxypropylene (flow rate: 56 ml / min, 582 mmol), and a combined acid methanol solution (flow rate: 0.9 mL / min, dihydronerol flow rate ratio 0.02, 20% of total acid content) were pumped into a single-stage tubular plug flow reactor, and the temperature was controlled at 90-100℃.

[0120] After the flow rate stabilized, a combined acid methanol solution (flow rate: 1.8 mL / min, flow rate ratio to dihydroneryl alcohol 0.04, 40% of the total acid) was pumped into the 2-stage tubular plug flow reactor, with the temperature controlled at 100-110℃. After the flow rate stabilized, a combined acid methanol solution (flow rate: 1.8 mL / min, flow rate ratio to dihydroneryl alcohol 0.04, 40% of the total acid) was pumped into the 3-stage tubular plug flow reactor, with the temperature controlled at 110-120℃. After the flow rate stabilized, the reaction liquid flowing out of the 3-stage tubular plug flow reactor was collected, and the components were analyzed by gas chromatography: dihydrofarnesylacetone / dihydroneryl alcohol = 97.1 / 0.3.

[0121] 1 L of material was collected and distilled to obtain a yield of 96.1% and a residue of 2.9%.

[0122] The data from Examples 11-15 are summarized in Table 3 below: (Dihydronerol flow rate: 2-methoxypropene flow rate = 50 mL / min: 56 mL / min) Preparation of dihydrofarnesyacetone;

[0123] Table 3(a)

[0124]

[0125] Table 3(b)

[0126]

[0127] Comparative Example 3

[0128] Prepare a mixed solution of phosphoric acid and phosphoric acid: Dissolve the combined acid with a phosphoric acid molar ratio of 15% in 5 times the amount of methanol to prepare a molar concentration of 1.9 mmol / mL. The ratio of the total flow rate of the acid solution to the flow rate of dihydroneretol is 0.10, the total acid flow rate is 5.2 ml / min, and the molar equivalent is 0.05.

[0129] Dihydronerol (flow rate: 50 ml / min, 194 mmol), 2-methoxypropylene (flow rate: 56 ml / min, 582 mmol), and a combined acid methanol solution (flow rate: 5.2 mL / min, dihydronerol flow rate ratio 0.10, 100% of total acid content) were pumped into a single-stage tubular plug flow reactor, and the temperature was controlled at 90-100℃.

[0130] The temperature control for the 2-stage tubular plug flow reactor is 100-110℃, and the temperature control for the 3-stage tubular plug flow reactor is 110-120℃. After the flow rate stabilizes, the reaction liquid flowing out of the 3-stage tubular plug flow reactor is collected and the components are analyzed by gas chromatography: dihydrofarnesylacetone / dihydronerol = 89.6 / 8.1.

[0131] 1 L of material was collected and distilled to obtain a yield of 86.3% and a residue of 5.1%.

Claims

1. A method for preparing compound II, characterized in that, It includes the following steps: in a tubular reactor, in the presence of acid, compound I and 2-methoxypropylene react to produce compound II; ； Among them, R1 and R2 are independently selected from hydrogen, C1-C 12 Alkyl and C2-C 12 alkenyl; The acid is phosphorous acid or a combination of phosphorous acid and phosphoric acid; The acid is added in the following manner: In the first stage, the molar ratio of the acid to compound I is 0.005-0.015; In the second stage, the molar ratio of the acid to compound I is 0.006-0.020; In the third stage, the molar ratio of the acid to compound I is 0.009-0.025; The tubular reactor is a three-stage tubular plug flow reactor.

2. The preparation method according to claim 1, characterized in that, It satisfies one or more of the following conditions: (1) The C1-C 12 The alkyl group is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, or... ; (2) The C2-C 12 The alkenyl group is vinyl, propenyl, butenyl or ; (3) The flow rate of compound I is 25-100 mL / min; (4) The acid is a combination of phosphorous acid and phosphoric acid; (5) The acid is an acid solution soluble in methanol; (6) The molar ratio of the acid to compound I is 0.01 to 0.1; (7) The total flow rate of the acid is 3~15 mL / min; (8) The molar ratio of 2-methoxypropylene to compound I is 2 to 5; (9) The flow rate of the 2-methoxypropylene is 50~150 mL / min; (10) The reaction temperature is 90~120℃.

3. The preparation method according to claim 2, characterized in that, It satisfies one or more of the following conditions: (1) The C1-C 12 The alkyl group is methyl or ; (2) The C2-C 12 The alkenyl group is ; (3) In the combined acid, the proportion of phosphoric acid is 0%~40%; (4) The flow rate of compound I is 50 mL / min; (5) The molar ratio of the acid to compound I is 0.01-0.05; (6) The total flow rate of the acid is 12.5 mL / min, 12.2 mL / min, 10.1 mL / min, 7.2 mL / min, 7.1 mL / min, 5.8 mL / min, 5.2 mL / min or 4.4 mL / min; (7) The molar ratio of 2-methoxypropylene to compound I is 3; (8) The flow rate of the 2-methoxypropylene is 56 mL / min, 79 mL / min or 139 mL / min; (8) In the tubular reactor, the liquid holding volume of each section of the tubular reactor is 50~200 mL; (10) The pressure of the tubular reactor is 0.3~2.0MPa.

4. The preparation method according to claim 2, characterized in that, In the first stage, one or more of the following conditions are met: (1) The molar ratio of the acid to compound I is 0.005, 0.006, 0.008, 0.010, 0.012 or 0.013; (2) The volumetric flow rate ratio of the acid to compound I is 0.02-0.06; (3) The reaction temperature is 90~100℃.

5. The preparation method according to claim 2, characterized in that, In the second stage, one or more of the following conditions are met: (1) The molar ratio of the acid to compound I is 0.006, 0.009, 0.011, 0.012, 0.015 or 0.018; (2) The volumetric flow rate ratio of the acid to compound I is 0.02-0.10; (3) The reaction temperature is 100~110℃.

6. The preparation method according to claim 2, characterized in that, In the third stage, one or more of the following conditions must be met: (1) The molar ratio of the acid to compound I is 0.009, 0.012, 0.014, 0.020 or 0.025; (2) The volumetric flow rate ratio of the acid to compound I is 0.03-0.11; (3) The reaction temperature is 110~120℃.

7. The preparation method according to claim 2, characterized in that, It satisfies one or more of the following conditions: (1) Compound I is methylbutenol, dihydrolinalool or dihydroneryl alcohol; (2) In the first stage, the volumetric flow rate ratio of the acid to the compound I is 0.06, 0.05, 0.04, 0.03 or 0.02; (3) In the second stage, the volumetric flow rate ratio of the acid to the compound I is 0.10, 0.09, 0.07, 0.06, 0.05, 0.04, 0.03 or 0.02; (4) In the third stage, the volumetric flow rate ratio of the acid to compound I is 0.11, 0.10, 0.06, 0.05, 0.04 or 0.03; (5) The molar ratio of the acid to compound I is 0.02, 0.03, 0.04 or 0.05; (6) The liquid holding volume of the tubular reactor is 100 mL.

8. The preparation method according to claim 2, characterized in that, It satisfies one or more of the following conditions: (1) When compound I is methylbutenol, the proportion of phosphoric acid in the combined acid is 0-10%; (2) When compound I is dihydrolinalool, the proportion of phosphoric acid in the combined acid is 10%-20%; (3) When compound I is dihydronerol, the proportion of phosphoric acid in the combined acid is 20-30%.

9. The preparation method according to claim 2, characterized in that, It satisfies one or more of the following conditions: (1) The molar concentration of the acid solution is 1.0~2.0 mmol / mL; (2) When compound I is methylbutenol, the proportion of phosphoric acid in the combined acid is 0%, 5% or 10%; (3) When compound I is dihydrolinalool, the proportion of phosphoric acid in the combined acid is 10%, 15% or 20%; (4) When compound I is dihydronerol, the proportion of phosphoric acid in the combined acid is 20%, 25% or 30%.

10. The preparation method according to claim 9, characterized in that, The molar concentration of the acid solution is 1.1 mmol / mL, 1.2 mmol / mL, 1.3 mmol / mL or 1.9 mmol / mL.

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