Continuous rectification process for high-quality dimethylbenzyl original butyrate

Abstract

The application discloses a continuous rectification process of high-quality dimethyl benzyl original butyrate, which comprises the following steps: S1, a separation inner wall is arranged in a rectification tower, the separation inner wall divides the rectification tower into a common rectification section, a feeding section, a feeding stripping section, a side line discharge section and a side line discharge stripping section, the lower part of the separation inner wall is vertical, the upper part is curved, and a connecting hole is arranged on the vertical part; S2, a reaction crude solution is fed into the feeding section from a feeding port, pre-separation is carried out in the feeding section, light components, main products and heavy components are preliminarily separated, the intermediate product containing the main products is taken out from the side line discharge section due to condensation, and the light components are returned to the common rectification section through a condenser and are separated again; and S3, part of the intermediate product is stripped through the side line discharge stripping section and then enters the feeding stripping section through the connecting hole. The yield of the purified dimethyl benzyl original butyrate is 98%, the proportion of the product with a purity of greater than or equal to 99% is 55%, and the aroma score of the product with a purity of 99.85% is 9.0.

Description

Technical Field

[0001] This invention relates to the chemical industry, and more particularly to a continuous distillation process for high-quality dimethyl benzyl butyrate. Background Technology

[0002] Dimethyl benzyl butyrate is a colorless to pale yellow liquid with a strong fruity and floral aroma. It has a molecular weight of 230.32, a boiling point of 265℃, and a density of 0.982 g / cm³. Dimethyl benzyl butyrate is insoluble in water but soluble in organic solvents such as ethanol and ether. It is chemically stable, but may undergo oxidation at high temperatures or after prolonged exposure to air. Dimethyl benzyl butyrate is a commonly used fragrance ingredient, widely used in perfumes, aromatherapy products, soaps, shampoos, conditioners, shower gels, and cosmetics to provide a warm, sweet aroma.

[0003] Conventional distillation has significant limitations in separating dimethyl benzyl butyrate. Not only is the separation effect poor, but the product's easy decomposition leads to reduced purity. Furthermore, the strong pungent odor of butyric acid and butyric anhydride severely affects the aroma quality of the final product, orthobutyrate. Additionally, the high boiling point of orthobutyrate necessitates a large amount of steam for distillation, resulting in higher costs. Currently, no publicly available distillation process for dimethyl benzyl butyrate is available in the industry. Therefore, this paper proposes a feasible approach to optimize the distillation method for dimethyl benzyl butyrate, aiming to obtain a high-quality product while reducing costs. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a continuous distillation process for high-quality dimethyl benzyl butyrate. Using this invention for the purification of dimethyl benzyl butyrate results in high-purity dimethyl benzyl butyrate with excellent aroma quality. Specifically, the process includes the following steps:

[0005] S1. The distillation column is provided with a partitioned inner wall, which divides the distillation column into five parts: a common rectification section, a feed section, a feed stripping section, a side stream discharge section, and a side stream discharge stripping section. The lower part of the partitioned inner wall is vertical and the upper part is curved, and the vertical part has connecting holes. The theoretical number of plates in the feed stripping section is 2-5, the theoretical number of plates in the feed section is 5-15, the theoretical number of plates in the common rectification section is 5-10, the theoretical number of plates in the side stream discharge section is 3-10, and the theoretical number of plates in the side stream discharge stripping section is 2-8.

[0006] S2. The reaction stock solution enters the feed section from the feed inlet. Pre-separation is carried out in the feed section to initially separate the light components, main products and heavy components. The light components and main products enter the common rectification section for further separation. The intermediate product containing the main product enters the side stream discharge section due to condensation. The main product is collected. The light components are refluxed to the common rectification section through the condenser for further separation.

[0007] S3. After being distilled by the side-stream distillation section, some intermediate products enter the feed distillation section through the connecting hole, and the residue is discharged through the residue port at the bottom of the vessel.

[0008] Preferably, the distillation column has 5 trays in the feed stripping section, 10 trays in the feed section, 12 trays in the common rectification section, 7 trays in the side stream discharge section, and 6 trays in the side stream discharge stripping section.

[0009] Preferably, the feed inlet is located at the 2nd to 9th trays of the feed section, and the discharge outlet is located at the 2nd to 4th trays of the side discharge section.

[0010] Preferably, the feed inlet is located at the fifth tray of the feed section, and the discharge outlet is located at the second tray of the side discharge section.

[0011] Preferably, the connection hole is a flange control switch.

[0012] Preferably, the upper part of the inner wall of the partition is bent to the side but does not contact the tower wall, and the lower vertical part is movably connected to the upper bent part, wherein the upper bent part is detachable and replaceable.

[0013] Preferably, the vertical distance between the upper feed inlet and the bottom of the tower is less than the vertical distance between the highest point of the inner wall of the partition and the bottom of the tower.

[0014] Preferably, the process parameters are set as follows: vacuum degree of 100-250 Pa, bottom temperature of distillation column of 130-170℃, top temperature of column of 40-60℃, and side stream outlet temperature of 75-95℃.

[0015] Preferably, the specific components of the reaction stock solution are: toluene 0-2%, dimethyl benzyl orthoester butyrate 85-95%, dimethyl benzyl orthoester (orthoester) 0-2% or more, other impurities about 5-10%, the remainder being water, and the total mass fraction is 100%.

[0016] Preferably, the light components are mainly toluene, butyric acid, (2-methylallyl)benzene, 2-methyl-1-phenylpropene, etc., the side stream discharge is more than 99% dimethyl benzyl butyrate, and the bottom of the reactor contains polymeric heavy components.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 1. The yield of dimethyl benzyl butyrate purified by this invention is greater than 96%, of which the proportion of purity ≥98% is greater than 66%, with a maximum of 80%; and the proportion of purity ≥99% is greater than 45%, with a maximum of 55%.

[0019] 2. The aroma scores of the products were all above 7.5, with the highest being 9.0, indicating a significant improvement in aroma quality.

[0020] 3. The curved structure of the inner wall of the separator expands the space of the feed section, improving the efficiency and effect of pre-separation. On the other hand, it reduces the amount of intermediate products entering the side discharge section inlet, improving product accuracy. At the same time, it allows the main gaseous products in the side discharge section to contact the inner wall of the separator and condense when they move upward, reducing the escape of the main products and improving the reaction yield. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a simplified process flow diagram of a continuous distillation process for high-quality dimethyl benzyl butyrate according to an embodiment of the present invention.

[0023] Figure 2 This is a GC map of an embodiment of the present invention.

[0024] In the diagram: 1. Distillation column, 2. Inner wall of partition, 3. Common distillation section, 4. Feed section, 5. Side stream discharge section, 6. Feed stripping section, 7. Side stream discharge stripping section, 8. Feed inlet, 9. Top outlet, 10. Condenser, 11. Upper feed inlet, 12. Side stream outlet, 13. Bottom residue outlet, 14. Flange switch. Detailed Implementation

[0025] Example 1

[0026] refer to Figure 1 A continuous distillation process for high-quality dimethyl benzyl butyrate includes the following steps:

[0027] 1. The distillation column has a partitioned inner wall that divides the distillation column into five parts: a common distillation section, a feed section, a feed stripping section, a side stream discharge section, and a side stream discharge stripping section. The upper part of the partitioned inner wall bends towards the side stream but is not connected to the column wall, while the lower part is vertical and has a flange control switch.

[0028] 2. The composition is 1.95% toluene, 86.85% dimethyl benzyl butyrate, 1.05% methyl alcohol, approximately 8.15% impurities, and the remainder is water. The total mass fraction of the reaction stock solution is 100%. It enters from the feed inlet located at the third tray of the feed section. The feed section has 6 trays. The set temperature of the column bottom is 145℃, the temperature of the column top is 55℃, and the vacuum degree is 200 Pa. Pre-separation is carried out in the feed section to initially separate the light components, the main product, and the heavy components. After the light components and the main product enter the common distillation process. The common rectification section has 7 trays. The intermediate product containing the main product enters the side stream discharge section due to condensation. The side stream discharge section has 3 trays, and the discharge port is located at the second tray of the side stream discharge section. The side stream discharge temperature is 82℃. The light component discharge port is monitored in real time. The light component is refluxed to the common rectification section through the condenser for further separation. The light component components removed from the top of the column are toluene, butyric acid, (2-methylallyl)benzene, 2-methyl-1-phenylpropene, trace amounts of dimethyl benzyl butyrate, and other impurities.

[0029] 3. A portion of the intermediate product, after being refined in the side-stream stripping section, enters the feed stripping section through a flange to achieve internal circulation within the column. Unrefined dimethyl benzyl butyrate continues to be refined. The side-stream stripping section has 5 trays, and the feed stripping section has 3 trays. The bottom residue mainly consists of polymer and a very small amount of dimethyl benzyl butyrate, approximately 1% of the total composition, which is discharged through the flange and the bottom residue port.

[0030] Example 2

[0031] The difference between this embodiment and Embodiment 1 is that the number of trays in the feed stripping section is 5, the number of trays in the feed section is 10, the number of trays in the common rectification section is 12, the number of trays in the side stream stripping section is 7, the number of trays in the side stream stripping section is 6, the feed inlet is located at the 5th tray in the feed section, and the discharge outlet is located at the 2nd tray in the side stream stripping section.

[0032] The process parameters are: vacuum degree of 210 Pa, bottom temperature of 146°C, top temperature of 56°C, and side stream discharge temperature of 84°C.

[0033] The composition of the reaction stock solution is as follows: 1.50% toluene, 89.13% dimethyl benzyl butyrate, 0.8% ethanol, approximately 6.37% other impurities, and the remainder is water, with a total mass fraction of 100%.

[0034] The rest is exactly the same as in Example 1.

[0035] Example 3

[0036] The difference between this embodiment and Embodiment 1 is that the number of trays in the feed stripping section is 4, the number of trays in the feed section is 11, the number of trays in the common rectification section is 10, the number of trays in the side stream stripping section is 8, the number of trays in the side stream stripping section is 5, the feed inlet is located at the 6th tray in the feed section, and the outlet is located at the 3rd tray in the side stream stripping section.

[0037] The process parameters are: vacuum degree of 195 Pa, bottom temperature of 144°C, top temperature of 55°C, and side outlet temperature of 82°C.

[0038] The composition of the reaction stock solution is as follows: 1.75% toluene, 87.56% dimethyl benzyl butyrate, 1.10% ethanol, approximately 7.07% impurities, and the remainder is water, with a total mass fraction of 100%.

[0039] The rest is exactly the same as in Example 1.

[0040] Comparative Example 1

[0041] The reaction stock solution was distilled using a conventional distillation column. The specific components of the reaction stock solution were: 1.35% toluene, 88.47% dimethyl benzyl butyrate, 1.31% ethanol, approximately 7.65% other impurities, and the remainder being water, with a total mass fraction of 100%.

[0042] The process parameters are: vacuum degree of 150 Pa, bottom temperature of 130-260℃, and top temperature of 40-88℃.

[0043] The conventional distillation column has 14 trays.

[0044] Comparative Example 2

[0045] The reaction stock solution was distilled using a conventional distillation column. The specific components of the reaction stock solution were: 1.96% toluene, 87.39% dimethyl benzyl butyrate, 1.54% ethanol, approximately 6.65% other impurities, and the remainder being water, with a total mass fraction of 100%.

[0046] The process parameters are: vacuum degree of 150 Pa, bottom temperature of 130-260℃, and top temperature of 40-88℃.

[0047] The conventional distillation column has 14 trays.

[0048] Detection and Results

[0049] The product was tested, and the results are shown in Table 1.

[0050] Table 1

[0051]

[0052] As shown in Table 1, the purity of the dimethyl benzyl butyrate purified by this invention is ≥99% in more than 45% of the products, with the highest being 55%. The effect is significantly better than that of the comparative example. The aroma scores of the products are all above 7.5, while the aroma scores of the comparative products are all below 6.5, indicating a significant improvement in aroma quality. With 5 trays in the feed stripping section, 10 trays in the feed section, 12 trays in the common rectification section, 7 trays in the side stream stripping section, and 6 trays in the side stream stripping section, the feed inlet is located at the 5th tray in the feed section, and the outlet is located at the 2nd tray in the side stream stripping section; and the process parameters are set as follows: vacuum degree of 210 Pa, bottom temperature of 146℃, top temperature of 56℃, and side stream stripping temperature of 84℃, the purified dimethyl benzyl butyrate distillation yield is 98%, the percentage of products with a purity ≥99% is 55%, and the aroma score of products with a purity of 99.85% is 9.0.

[0053] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0054] In this invention, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," "link," and "fix" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0055] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A continuous distillation process for high-quality dimethyl benzyl butyrate, characterized in that, Includes the following steps: S1. The distillation column (1) is provided with a partition wall (2), which divides the distillation column into five parts: a common distillation section (3), a feed section (4), a feed stripping section (6), a side stream discharge section (5), and a side stream discharge stripping section (7). The partition wall (2) includes a vertical lower part and a curved upper part, and a connection hole (14) is provided on the vertical lower part of the partition wall (2). The theoretical number of plates in the feed stripping section (6) is 2-5, the theoretical number of plates in the feed section (4) is 5-15, the theoretical number of plates in the common distillation section (3) is 5-10, the theoretical number of plates in the side stream discharge section (5) is 3-10, and the theoretical number of plates in the side stream discharge stripping section (7) is 2-8. S2. The reaction stock solution enters the feed section (4) from the feed inlet (8). Pre-separation is carried out in the feed section to initially separate the light components, main products and heavy components. The light components and main products enter the common rectification section (3) for further separation. The intermediate product containing the main product enters the side discharge section (5) due to condensation. The main product is collected from the side discharge port (12). The light components are returned to the common rectification section (3) for further separation through the condenser (10) and the upper feed port (11) set on the distillation column (1). The specific components of the reaction stock solution are: toluene 0-2%, dimethyl benzyl butyrate 85-95%, dimethyl benzyl alcohol 0-2%, impurities 5-10%, and the remainder is water, with a total mass fraction of 100%. S3. After being distilled by the side-stream distillation section (7), some intermediate products enter the feed distillation section (6) through the connecting hole, and the residue is discharged through the bottom residue port (13).

2. The continuous distillation process for high-quality dimethyl benzyl butyrate as described in claim 1, characterized in that, A flange control switch is installed at the connection hole.

3. The continuous distillation process for high-quality dimethyl benzyl butyrate as described in claim 1, characterized in that, The upper part of the partition inner wall (2) bends toward the side of the side outlet (12), and the lower vertical part of the partition inner wall (2) is movably connected to the upper part of the bend, wherein the upper part of the bend is detachable and replaceable.

4. The continuous distillation process for high-quality dimethyl benzyl butyrate as described in claim 1, characterized in that, The vertical distance between the upper feed inlet (11) and the bottom of the tower is less than the vertical distance between the highest point of the inner wall of the partition and the bottom of the tower.

5. The continuous distillation process for high-quality dimethyl benzyl butyrate as described in claim 1, characterized in that, The process parameters are set as follows: vacuum degree of 100-250 Pa, bottom temperature of distillation column of 130-170℃, top temperature of column of 40-60℃, and side stream outlet temperature of 75-95℃.

6. The continuous distillation process for high-quality dimethyl benzyl butyrate as described in claim 1, characterized in that, The light components are mainly toluene, butyric acid, (2-methylallyl)benzene, and 2-methyl-1-phenylpropene. The side stream output is dimethyl benzyl butyrate with a purity of over 99%, and the bottom of the reactor contains polymeric heavy components.

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