Improved 1,3-butylene glycol process

Abstract

An improved process for producing low-impurity 1,3-butylene glycol includes: (a) aldolizing acetaldehyde in a reactor to produce acetaldol; (b) hydrogenating the acetaldol in a hydrogenation reactor in the presence of a hydrogenation / dehydrogenation catalyst to produce a crude 1,3-butylene glycol stream containing an active hydrogenation / dehydrogenation catalyst; (c) removing or deactivating catalyst in the crude 1,3-butylene glycol stream; and (d) distilling the treated crude 1,3-butylene glycol stream in a distillation train to provide a purified 1,3-butylene glycol product.

Description

[Technical Field]

[0001] Priority claim This international patent application is based on and claims priority from co-pending U.S. Provisional Patent Application No. 63 / 416,815 (Attorney Docket No. OQ-21 2), filed October 17, 2022, of the same title, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present invention relates to the production of 1,3-butylene glycol, and in particular to a high purity product suitable for cosmetic applications or applications where a low odor material is desired. [Background technology]

[0003] 1,3-Butylene glycol is used in the manufacture of plasticizers, polyol esters, and cosmetics. The products are traditionally produced by the aldolization of acetaldehyde, hydrogenation of the aldol in the presence of a hydrogenation / dehydrogenation catalyst, and subsequent purification of the crude product. A low-odor, high-purity product is required for cosmetic applications and is desirable in many other end uses.

[0004] US2003 / 0018224 (Tsuji et al.) (Patent Document 1) discloses various methods for producing high-purity 1,3-butylene glycol by hydrogenating acetaldol in the presence of a Raney nickel catalyst and distilling the crude mixture. It is stated that a relatively high activity Raney nickel catalyst achieves the desired results. See paragraphs

[0086] and

[0087] .

[0005] U.S. Patent No. 6,376,725 to Tsuji et al. discloses a method for producing high-purity 1,3-butylene glycol with low amounts of by-products and low odor. The method includes adding a base to crude 1,3-butylene glycol free of high-boiling substances, heat-treating the mixture, and then distilling off the 1,3-butylene glycol; and distilling off the low-boiling substances from the 1,3-butylene glycol. See column 2, lines 1-9.

[0006] GB1205689 (Celanese) (Patent Document 3) discloses a method for producing low-odor 1,3-butylene glycol, which includes distilling the product in a stainless steel vessel to avoid catalytic decomposition of the product by iron oxide, etc. See page 1, column 2, lines 62-77.

[0007] US2005 / 0154239 (Windhorst et al.) (Patent Document 4) discloses a method for producing 1,3-butylene glycol with low impurities by using an acetaldehyde feedstock with a low acid content. This method is reported to achieve a relatively high yield by minimizing by-products. See paragraph

[0018] .

[0008] Windhorst et al., US Pat. No. 8,445,733, discloses a method for reducing the odor of 1,3-butylene glycol by treating the product with activated carbon.

[0009] U.S. Patent No. 5,345,004 to Nishiguchi discloses a method for producing cosmetic-grade 1,3-butylene glycol with low by-products and low odor. The method removes crotonaldehyde from recycled acetaldehyde. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] US2003 / 0018224 [Patent Document 2] U.S. Patent No. 6,376,725 [Patent Document 3] GB1205689 [Patent Document 4] US2005 / 0154239 [Patent Document 5] U.S. Patent No. 8,445,733 [Patent Document 6] U.S. Patent No. 5,345,004 Summary of the Invention

[0011] The present invention provides an improved process for producing 1,3-butylene glycol (sometimes referred to herein as 1,3BG) by eliminating sources of impurities to produce cosmetic-grade, low-odor 1,3BG.

[0012] [ka] In connection with the present invention, it has been discovered that very low levels of hydrogenation / dehydrogenation catalyst residues in the crude product stream, e.g., greater than 100 ppm Raney nickel, catalyze the Guerbet reaction during the purification of 1,3BG, adversely affecting product quality. Conventional catalyst removal procedures, such as settling and filtration using conventionally used filtration systems, do not achieve the necessary reduction of previously used catalyst in the crude product. Without intending to be bound by theory, it is believed that the Guerbet reaction results in the catalytic generation of a major by-product, as shown in Scheme 1 below, Scheme 2 below, and the subsequent examples.

[0013] In Scheme 1, Scheme 2, and the following examples, it can be seen that 1,3BG decomposes in the presence of water and nickel at elevated temperatures with the release of hydrogen. Large amounts of 2-propanol, 2-butanol, and 1-butanol are detected, as well as significant amounts of 4-hydroxy-2-butanone and methyl vinyl ketone. These molecules are key intermediates in the various by-product formation pathways identified by the inventors herein (including pyran and other ethers). While not limited to the structures shown, some representative impurities observed include:

[0014] [ka] The conditions applied in the examples herein are equivalent and comparable to those applied in the purification section of a typical commercial unit.

[0015] Low levels of active hydrogenation / dehydrogenation catalyst in the crude product are the reason for this decomposition (there is no reaction in the absence of a catalyst). The Guerbet reaction was first recognized in 1899 and was linked to diols in the 1960s. See M. Guerbet: Action de l'alcohol amylique de fermentation sur son derive sode (Comptes rendus de l'Academie des sciences. Band 128, 1899, s. 511-513). Examples show the reaction initiated and catalyzed by Ni. For general information on the Guerbet reaction, see GB 761296 (Esso Research and Engineering Co.), page 2, column 2, line 92 to page 3, column 1, line 32.

[0016] In one aspect of the present invention, there is provided a method for producing 1,3-butylene glycol, comprising: (a) aldolizing acetaldehyde in a reactor to produce acetaldol; (b) hydrogenating the acetaldol in a hydrogenation reactor in the presence of a hydrogenation / dehydrogenation catalyst to produce a crude 1,3-butylene glycol stream having an active hydrogenation / dehydrogenation catalyst content of greater than 100 ppm; (c) removing or deactivating catalyst in said crude 1,3-butylene glycol stream to provide a treated crude 1,3-butylene glycol stream having less than 100 ppm of active hydrogenation / dehydrogenation catalyst; and (d) distilling the treated crude 1,3-butylene glycol stream in a distillation train to provide a purified 1,3-butylene glycol product.

[0017] In another aspect of the invention, an improvement is provided to the class of continuous processes for producing 1,3-butylene glycol that includes hydrogenating acetaldol in the presence of a hydrogenation / dehydrogenation catalyst in a hydrogenation reactor to produce a crude 1,3-butylene glycol stream containing an active hydrogenation / dehydrogenation catalyst, and distilling the crude 1,3-butylene glycol stream in a distillation train to provide a purified 1,3-butylene glycol product, the improvement including removing or deactivating active catalyst in the crude 1,3-butylene glycol stream to provide a treated crude 1,3-butylene glycol stream that has a lower activity than the crude 1,3-butylene glycol stream before treatment and that contains hydrogenation / dehydrogenation catalyst in the range of 0 to 750 ppm before distillation, and distilling the treated crude 1,3-butylene glycol stream in a distillation train to provide the purified 1,3-butylene glycol product.

[0018] Further aspects and details are provided in the discussion below. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 shows a schematic flow diagram of a typical continuous process for producing 1,3-butylene glycol according to the present invention.

[0020] Detailed Description The present invention will now be described in detail, by way of example only, with reference to the accompanying drawings. The invention is defined in the appended claims. Unless otherwise specified, the terms and symbols used herein shall be given their ordinary meaning; for example, terms such as %, ppm, etc. shall mean % by weight, parts by weight per million, etc., unless otherwise specified.

[0021] "Consisting essentially of" and similar terms refer to the listed ingredients and exclude other ingredients that would materially change the basic and novel characteristics of the composition, article, or process. Unless otherwise stated or readily apparent, a composition or article consists essentially of the listed or recited ingredients when the composition or article contains 90% or more by weight of the listed or recited ingredients. That is, the term excludes more than 10% of unlisted ingredients. Any of the products disclosed and claimed herein can consist essentially of the listed ingredients.

[0022] The "effective pore size" of a filtration system refers to the ability of that filtration system to filter out particles of a particular size. For example, a 0.20 micron (μm) rated filtration system will remove particles having a diameter of 0.2 microns or greater from the filtrate stream.

[0023] Filtration, filtration system, and similar terms refer to a single filtration element or multiple filtration elements, including filtration elements arranged in series or parallel, characterized by an effective pore size. Such filtration includes, but is not limited to, leaf-type systems, cartridge-type systems, bag-type systems, centrifugal systems, sedimentation systems, candle-type systems, and / or magnetic-type systems. It is preferred to use a filtration system having a primary filtration system followed by a secondary or polishing filtration system with a smaller effective pore size. The primary filtration may consist of a sedimentation device with or without one or more of the above-mentioned types of filters. Polishing filtration systems may include, but are not limited to, those mentioned above. Additionally, a precoat material can be added to improve both the primary and secondary system filtration capacity. Precoat-type materials can be of various types, including diatomaceous earth, perlite, and / or cellulose. The polishing filtration system preferably has an effective pore size of 1 micron or less.

[0024] "Guerbet impurities" or "Guerbet by-products" include 2-propanol, 2-butanol, 1-butanol, 4-hydroxy-2-butanone, methyl vinyl ketone, and by-products formed with these molecules, such as pyran and other ethers, representative by-products include:

[0025] [ka] As used herein, the term "hydrogenation / dehydrogenation catalyst" and similar terms refer to metal catalysts used to hydrogenate and dehydrogenate organic compounds, including transition metal catalysts selected from the list of metals Ti, Zr, V, Nb, Cr, Mo, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, and Hg. The catalyst may be in the form of a fixed bed, i.e., catalytic metal optionally supported on a carrier, or in the form of a slurry of supported or unsupported catalytic metal. Raney catalysts in slurry form selected from Raney-Co, Raney-Ni, Raney-Cu, and Raney-Fe are particularly preferred, which contain metals that may be included in the Raney catalyst as promoters without being bound during the catalyst production process, particularly Al, Zn, and Cr.

[0026] A typical 1,3BG process can be separated and simplified into three distinct steps: first, aldolization of acetaldehyde to 3-hydroxybutanal, second, hydrogenation of the latter to the corresponding crude diol, and third, purification of the crude 1,3-butylene glycol. The process can be run in either a batch or semi-continuous mode, or, more preferably, in a 100% continuous manner from the acetaldehyde feed to final purification of the product. A simplified overall process flow for the continuous process of the present invention is shown in Figure 1, which is a schematic representation of an apparatus for producing 1,3-butylene glycol, including the reactors, purification columns, and removal units described below.

[0027] Aldolization of acetaldehyde: The process description refers to the simplified process flow in Figure 1. A unit feeds acetaldehyde to aldolization reactor A. 2-20%, more preferably 2-10%, caustic is added to the reactor. Aldolization reactor A is operated at a conversion of 10-90%, more preferably 20-80%, and even more preferably 22-62%. The conversion is controlled by typical process parameters known to those skilled in the art. The reaction pressure is in the range of 20-70 psig, more preferably 30-60 psig, and even more preferably 25-50 psig, and the temperature is controlled between 30-130°F, more preferably 50-100°F, and even more preferably 60-90°F, for example, 70-85°F.

[0028] The reactor product is removed and sent to a stripper column to remove light ends from the product stream. Stripper Column B bottoms contains intermediates that are sent to the hydrogenation section of the unit.

[0029] Hydrogenation of acetaldol: Hydrogenation is accomplished using a metal-based catalyst, preferably from the list of Ti, Zr, V, Nb, Cr, Mo, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, and Hg metals, and even more preferably from the list of Raney-Co, Raney-Ni, Raney-Cu, Raney-Fe, or similar catalysts. Hydrogenation reactor C typically operates at 150-250°F, more suitably 180-230°F, even more suitably 190-220°F, and 500-800 psig, more suitably 600-750 psig, and even more suitably 650-720 psig. Hydrogen is supplied to the reactor and may be conducted through the reactor, for example, as a two-phase flow with the intermediate and the active hydrogenation catalyst. The hydrogenation product and some active hydrogenation catalyst emerge from the reactor. Unreacted hydrogen is separated from the crude reaction mixture, while the liquid phase is sent to a catalyst separation system D. The active catalyst is removed, conventionally by decanting and optionally filtration. The crude reaction product proceeds to purification E.

[0030] Purification (E): The pretreated crude 1,3-butylene glycol (1,3BG) emerging from hydrogenation contains both light and heavy impurities. The crude typically already contains a high amount of 1,3-butylene glycol in water, along with some light ends such as ethanol and / or butanol and / or crotonaldehyde and corresponding impurities. Heavy-end impurities include 2,6-dimethyl-1,3-dioxan-4-ol (aldoxane), 2-ethyl-1,3-butylene glycol and / or 2,4-dimethyl-1,3-dioxane (BG acetal) and / or 3-hydroxybutyl acetate (BG monoacetate). Water can comprise 50-90%, preferably 60-80%, and even more preferably 65-75% of the crude product stream, with the remainder consisting essentially of 1,3-butylene glycol.

[0031] Impurities can be removed in purification through a series of columns. In one variation of the invention, a first purification step can include removal of any light-end impurities, including water. In another variation of the invention, a second purification step can include removal of any heavy-ends, followed by a third and / or polishing step to provide odor-free, high-quality 1,3-butylene glycol. According to this invention, the corresponding purification step can include the use of a vacuum flusher.

[0032] Catalyst separation unit according to the invention (X, FIG. 1): However, in accordance with the present invention, in addition to or as an alternative to the catalyst separation train catalyst removal / deactivation described above, unit (X) is provided to reduce the active hydrogenation / dehydrogenation catalyst level to less than 1000 ppm, more preferably less than 500 ppm, even more preferably less than 150 ppm, 100 ppm or less, before the treated crude 1,3-butylene glycol stream is sent for further purification.

[0033] It is recommended that primary and secondary catalyst deactivation and / or removal systems be utilized as part of this invention to pre-treat the crude reaction product to reduce the level of active hydrogenation / dehydrogenation catalyst.

[0034] Primary catalyst deactivation and / or removal systems can include, but are not limited to, leaf-type systems, cartridge-type systems, bag-type systems, centrifugal systems, sedimentation systems, candle-type systems, and / or magnetic-type systems with or without sedimentation devices. Secondary catalyst deactivation or polishing filtration systems can include, but are not limited to, the foregoing. Additionally, precoat materials can be added to improve both the primary and polishing filtration system filtration capacity. Precoat-type materials can be of various types, including diatomaceous earth, perlite, and / or cellulose.

[0035] Deactivating transition metal-based hydrogenation / dehydrogenation catalysts is another viable route to prevent the decomposition of desired 1,3-butylene glycol and the formation of undesired by-products via the Guerbet reaction. Without being bound by theory, it is believed that the catalytic activity of the hydrogenation / dehydrogenation catalyst is determined by the active surface sites of the heterogeneous and / or homogeneous material that act as a catalyst. Therefore, deactivating the active sites can result in the suppression of undesired side reactions, which is a central part of the present invention.

[0036] Deactivation can be achieved by contacting the catalyst with hypochlorite, nitrate or nitrite-based solutions, solubilized carbon monoxide, phosphines, and / or any other components that potentially block the active surface from chemisorption and / or physisorption mechanisms. Contacting the crude process stream with deactivating ions prevents the formation of additional by-products. Crude process streams and / or process equipment can be treated continuously or discontinuously to deactivate transition metal catalysts present in unintended and / or intended locations.

[0037] The present invention reduces odor-causing impurities and allows for the elimination of finishing steps. [Example]

[0038] Experimental Example 1. Formation of by-products: A series of tests were conducted to determine the effect of residual active hydrogenation / dehydrogenation catalyst on impurity formation from crude 1,3-butylene glycol during downstream processing of the crude 1,3-butylene glycol.

[0039] General Procedure Under an inert gas atmosphere (Ar), 1,3-butylene glycol was dissolved in water (30 wt%) to represent a typical crude 1,3-butylene glycol stream and fed to a laboratory distillation apparatus equipped with a cold trap, a condensate collector, and a gas collector. The distillation temperature was maintained at 103°C.

[0040] The unit was operated with varying amounts of hydrogenation / dehydrogenation catalyst in aqueous 1,3-butylene glycol solution (including a benchmark with no catalyst) to investigate the effect of the latter.

[0041] Gases and condensates were collected and analyzed.

[0042] [Table 1.1]

[0043] [Table 1.2]

[0044] Impurity production correlates with hydrogen production according to Scheme 2 below:

[0045] [ka] In the absence of an active hydrogenation / dehydrogenation catalyst, there is no impurity formation, but already at 1 wt. % or 0.1 wt. %, the by-product formation is high enough to be detected by simple GC analysis (especially the lesser amounts of 4-hydroxy-2-butanone (4H2B), 1-butanol, and 2-butanol). As can be seen from the above scheme, 2-butanol is likely derived from 4H2B. Impurity formation decreases at about 100 ppm of catalyst in the mixture and is virtually absent at 10 ppm in the mixture.

[0046] Therefore, impurity production in commercial units is substantially improved when the active catalyst is removed or deactivated to a level equivalent to less than 100 ppm active catalyst prior to further processing of the crude product stream, which involves distilling the crude processed product at elevated temperatures.

[0047] 2. Filtration to prevent by-product formation: Filtration Procedure: Representative mixtures of 1,3-BG and water in the presence of 1% (w / w) transition metal catalyst were filtered using filter discs with various effective pore sizes. The material was passed through a single filter disc and subjected to the general procedural conditions for by-product formation described above. The distillate was collected and analyzed.

[0048] [Table 2.1]

[0049] In the above examples, filter paper discs were used, but those skilled in the art will appreciate that filtration systems including polyester discs or tubes, polypropylene discs or tubes, or sintered metal discs or tubes may also be used.

[0050] 3. Inactivation to prevent the formation of by-products Representative mixtures of 1,3-BG and water were exposed to deactivated and activated forms of the transition metal catalyst. Deactivation in the presence of excess deactivating ions relative to the transition metal catalyst showed differences in by-product formation.

[0051] Deactivation of Raney nickel using NaOCl solution (8-10% aqueous solution). Add Raney nickel (5 g) to a 250 mL round-bottom flask containing water (35 g) and add 8-10% aqueous NaClO (150 g, approximately 100% excess based on Raney nickel) within 10 min. During the addition, the temperature of the mixture rises from room temperature (approximately 20 °C) to 41 °C. After complete addition, the mixture is then stirred at 60 °C for 1 h.

[0052] The mixture is then cooled to room temperature, the catalyst is filtered and washed with water, and the deactivated catalyst is stored moist until use.

[0053] Deactivation of Raney nickel using NaNO3 solution (10% aqueous solution) Raney nickel (20 g) is added to a 500 mL round-bottom flask containing water (80 g) and NaNO (approximately 6% excess based on Raney nickel, 300 g) is added within 25 min. During the addition, the temperature rises from room temperature (approximately 20 °C) to 33 °C. After complete addition, the mixture is subsequently stirred at 60 °C for 1 h.

[0054] The mixture is then cooled to room temperature, the catalyst is filtered and washed with water, and the deactivated catalyst is stored moist until use.

[0055] [Table 3.1]

[0056] Although the present invention has been described in detail, modifications within the spirit and scope of the present invention will be apparent to those skilled in the art. Such modifications are also considered part of the present invention. In view of the foregoing discussion, the relevant knowledge in the art in conjunction with the above description (including the Summary of the Invention and Background), and the references discussed above (all of which are incorporated herein by reference), further explanation is not believed to be necessary. Furthermore, it will be understood from the above discussion that aspects and various embodiments of the present invention can be combined or interchanged, in whole or in part. Furthermore, it will be understood by those skilled in the art that the above description is by way of example only and is not intended to limit the present invention.

Claims

1. below: (a) aldolizing acetaldehyde in a reactor to form acetaldol; (b) hydrogenating the acetaldol in a hydrogenation reactor in the presence of a hydrogenation / dehydrogenation catalyst to produce a crude 1,3-butylene glycol stream having an active hydrogenation / dehydrogenation catalyst content of greater than 100 ppm; (c) removing or deactivating catalyst in said crude 1,3-butylene glycol stream to provide a treated crude 1,3-butylene glycol stream having less than 100 ppm of active hydrogenation / dehydrogenation catalyst; and (d) distilling the treated crude 1,3-butylene glycol stream in a distillation train to provide a purified 1,3-butylene glycol product; A method for producing 1,3-butylene glycol, comprising:

2. 10. The method of claim 1, wherein the hydrogenation / dehydrogenation catalyst comprises a transition metal hydrogenation / dehydrogenation catalyst.

3. 3. The method of claim 2, wherein the hydrogenation / dehydrogenation catalyst comprises a transition metal hydrogenation / dehydrogenation catalyst selected from Ti, Zr, V, Nb, Cr, Mo, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd and Hg metals.

4. 4. The process of claim 3, wherein the hydrogenation / dehydrogenation catalyst is a Raney catalyst selected from Raney-Co, Raney-Ni, Raney-Cu, Raney-Fe, optionally containing one or more of Al, Zn, and Cr.

5. 10. The process of claim 1, wherein the hydrogenation / dehydrogenation catalyst is a Raney nickel catalyst.

6. The process of any one of claims 1 to 5, wherein the hydrogenation / dehydrogenation catalyst is a slurry catalyst.

7. 7. The process of any one of claims 1 to 6, wherein the treated crude 1,3-butylene glycol stream contains less than 75 ppm of active hydrogenation / dehydrogenation catalyst.

8. 8. The process of claim 7, wherein the treated crude 1,3-butylene glycol stream contains less than 50 ppm of active hydrogenation / dehydrogenation catalyst.

9. 9. The process of claim 8, wherein the treated crude 1,3-butylene glycol stream contains less than 25 ppm of active hydrogenation / dehydrogenation catalyst.

10. 10. The process of claim 9, wherein the treated crude 1,3-butylene glycol stream contains less than 12.5 ppm of active hydrogenation / dehydrogenation catalyst.

11. 11. The process of any one of claims 1 to 10, further comprising removing and / or deactivating residual catalyst from the surfaces of the distillation train.

12. 12. The process of any one of claims 1 to 11, wherein the active hydrogenation / dehydrogenation catalyst in the crude 1,3-butylene glycol stream is deactivated with a deactivating agent effective to block active catalytic sites on the hydrogenation / dehydrogenation catalyst.

13. 13. The method of claim 12, wherein the active hydrogenation / dehydrogenation catalyst in the crude 1,3-butylene glycol stream is deactivated with a molar excess of the deactivating agent relative to the catalyst present.

14. 14. The method of claim 12 or 13, wherein deactivating the catalyst in the crude 1,3-butylene glycol stream is carried out by contacting the catalyst with a deactivating agent selected from hypochlorite, nitrate or nitrite based solutions, solubilized carbon monoxide and phosphines.

15. 15. The process of any one of claims 1 to 14, wherein the crude 1,3-butylene glycol stream containing residual active hydrogenation / dehydrogenation catalyst is filtered through a filtration system having an effective pore size of 0.01 to 1 micron.

16. 16. The method of claim 15, wherein the filtration system is a leaf system, a cartridge system, a bag system, a centrifugal system, a sedimentation system, a candle system, a magnetic system, or a combination thereof.

17. 17. The method of claim 15 or 16, wherein the filtration system has an effective pore size of 0.01 to 0.5 microns.

18. 17. The method of claim 15 or 16, wherein the filtration system has an effective pore size of 0.01 to 0.25 microns.

19. 17. The method of claim 15 or 16, wherein the filtration system has an effective pore size of 0.01 to 0.1 microns.

20. 20. The method of any one of claims 1 to 19, wherein the purified 1,3-butylene glycol product has less than 1% Guerbet impurities.

21. 21. The method of any one of claims 1 to 20, wherein the purified 1,3-butylene glycol product has less than 0.5% Guerbet impurities.

22. 22. The method of any one of claims 1 to 21, wherein the purified 1,3-butylene glycol product has less than 0.25% Guerbet impurities.

23. 23. The method of any one of claims 1 to 22, wherein the purified 1,3-butylene glycol product has 0% to 0.5% Guerbet impurities.

24. In a class of continuous processes for producing 1,3-butylene glycol comprising hydrogenating acetaldol in the presence of a hydrogenation / dehydrogenation catalyst in a hydrogenation reactor to produce a crude 1,3-butylene glycol stream comprising an active hydrogenation / dehydrogenation catalyst, and distilling the crude 1,3-butylene glycol stream in a distillation train to provide a purified 1,3-butylene glycol product, the improvement comprises removing or deactivating the active catalyst in the crude 1,3-butylene glycol stream to provide a treated crude 1,3-butylene glycol stream having a lower activity than the crude 1,3-butylene glycol stream before treatment and comprising hydrogenation / dehydrogenation catalyst in the range of 0 to 750 ppm before distillation, and distilling the treated crude 1,3-butylene glycol stream in a distillation train to provide a purified 1,3-butylene glycol product.

25. 25. The improvement of claim 24, wherein the content of active hydrogenation / dehydrogenation catalyst in the treated crude 1,3-butylene glycol stream is in the range of 0 to 500 ppm before distillation.

26. 25. The improvement of claim 24, wherein the content of active hydrogenation / dehydrogenation catalyst in the treated crude 1,3-butylene glycol stream is in the range of 0 to 250 ppm before distillation.

27. 25. The improvement of claim 24, wherein the content of active hydrogenation / dehydrogenation catalyst in the treated crude 1,3-butylene glycol stream is in the range of 0 to 100 ppm before distillation.

28. 25. The improvement of claim 24, wherein the content of active hydrogenation / dehydrogenation catalyst in the treated crude 1,3-butylene glycol stream is in the range of 0 to 50 ppm before distillation.

29. 25. The improvement of claim 24, wherein the content of active hydrogenation / dehydrogenation catalyst in the treated crude 1,3-butylene glycol stream is in the range of 0 to 25 ppm before distillation.

30. 25. The improvement of claim 24, wherein the content of active hydrogenation / dehydrogenation catalyst in the treated crude 1,3-butylene glycol stream is in the range of 0 to 12.5 ppm before distillation.

31. An improvement according to claim 24, incorporating one or more features selected from claims 1 to 23.

32. below: (a) an aldolization reactor for aldolizing acetaldehyde to acetaldol; (b) a hydrogenation reactor connected to the aldolization reactor, the hydrogenation reactor containing a slurry hydrogenation / dehydrogenation catalyst for hydrogenating the acetaldol from the aldolization reactor, the hydrogenation reactor operating to provide a crude 1,3-butylene glycol stream containing an active hydrogenation / dehydrogenation catalyst; (c) a catalyst removal / deactivation unit connected to the hydrogenation reactor, adapted to remove or deactivate active hydrogenation / dehydrogenation catalyst in the crude 1,3-butylene glycol stream, the catalyst removal / deactivation unit effective to remove or deactivate active catalyst in the crude 1,3-butylene glycol stream to provide a treated crude 1,3-butylene glycol stream having a lower activity than the crude 1,3-butylene glycol stream prior to treatment in the catalyst removal / deactivation unit and comprising hydrogenation / dehydrogenation catalyst in the range of 0 to 750 ppm; and (d) a distillation train connected to said catalyst removal / deactivation unit for producing said treated crude 1,3-butylene glycol product stream; An apparatus for producing 1,3-butylene glycol, comprising:

33. 33. The apparatus of claim 32, wherein the catalyst removal / deactivation unit operates to reduce the content of active hydrogenation / dehydrogenation catalyst in the crude 1,3-butylene glycol stream so that the treated crude 1,3-butylene glycol stream has an active hydrogenation / dehydrogenation catalyst content in the range of 0 to 500 ppm.

34. 33. The apparatus of claim 32, wherein the catalyst removal / deactivation unit operates to reduce the content of active hydrogenation / dehydrogenation catalyst in the crude 1,3-butylene glycol stream so that the treated crude 1,3-butylene glycol stream has an active hydrogenation / dehydrogenation catalyst content in the range of 0 to 250 ppm.

35. 33. The apparatus of claim 32, wherein the catalyst removal / deactivation unit operates to reduce the content of active hydrogenation / dehydrogenation catalyst in the crude 1,3-butylene glycol stream so that the treated crude 1,3-butylene glycol stream has an active hydrogenation / dehydrogenation catalyst content in the range of 0 to 100 ppm.

36. 33. The apparatus of claim 32, wherein the catalyst removal / deactivation unit operates to reduce the content of active hydrogenation / dehydrogenation catalyst in the crude 1,3-butylene glycol stream so that the treated crude 1,3-butylene glycol stream has an active hydrogenation / dehydrogenation catalyst content in the range of 0 to 50 ppm.

37. 33. The apparatus of claim 32, wherein the catalyst removal / deactivation unit operates to reduce the content of active hydrogenation / dehydrogenation catalyst in the crude 1,3-butylene glycol stream so that the treated crude 1,3-butylene glycol stream has an active hydrogenation / dehydrogenation catalyst content in the range of 0 to 25 ppm.

38. 33. The apparatus of claim 32, wherein the catalyst removal / deactivation unit operates to reduce the content of active hydrogenation / dehydrogenation catalyst in the crude 1,3-butylene glycol stream so that the treated crude 1,3-butylene glycol stream has an active hydrogenation / dehydrogenation catalyst content in the range of 0 to 12.5 ppm.

39. 39. The apparatus of any one of claims 32 to 38, wherein the crude 1,3-butylene glycol stream containing residual active hydrogenation / dehydrogenation catalyst is filtered in the catalyst removal / deactivation unit in a primary filtration system and subsequently in a polishing filtration system.

40. 40. The apparatus of any one of claims 32 to 39, wherein the crude 1,3-butylene glycol stream containing residual active hydrogenation / dehydrogenation catalyst is filtered in a polishing filtration system in the catalyst removal / deactivation unit having an effective pore size of 0.01 to 1 micron.

41. 41. The apparatus of claim 39 or 40, wherein the polishing filtration system is a leaf system, a cartridge system, a bag system, a centrifugal system, a sedimentation system, a candle system, a magnetic system, or a combination thereof.

42. 41. The apparatus of claim 39 or 40, wherein the polishing filtration system has an effective pore size of 0.01 to 0.5 microns.

43. 41. The apparatus of claim 39 or 40, wherein the polishing filtration system has an effective pore size of 0.01 to 0.25 microns.

44. 41. The apparatus of claim 39 or 40, wherein the polishing filtration system has an effective pore size of 0.01 to 0.1 microns.

45. 45. The apparatus of any one of claims 32 to 44, wherein the active hydrogenation / dehydrogenation catalyst in the crude 1,3-butylene glycol stream is deactivated in the catalyst removal / deactivation unit with a deactivating agent effective to block active catalytic sites on the hydrogenation / dehydrogenation catalyst.

46. 46. ​​The apparatus of claim 45, wherein the active hydrogenation / dehydrogenation catalyst in the crude 1,3-butylene glycol stream is deactivated with a molar excess of the deactivating agent relative to the catalyst present in the crude 1,3-butylene glycol stream.

47. 47. The apparatus of claim 45 or 46, wherein the deactivation of the catalyst in the crude 1,3-butylene glycol stream is carried out by contact with a deactivating agent selected from hypochlorite, nitrate or nitrite based solutions, solubilized carbon monoxide and phosphines and combinations.

Images