Process for the production of acetone with low aldehyde content

Abstract

Methods and systems for the production of acetone from cumene hydroperoxide (CHP) are disclosed. The methods and systems involve an acetone purification column configured to separate acetone from other components of the product / reactant stream. The acetone purification column is equipped with a side draw configured to transport a portion of the column contents to a caustic treatment vessel where the contents react with a dilute alkaline aqueous solution to remove aldehydes from the acetone product. The contents of the caustic treatment vessel are then transported back to the acetone purification column. The use of a separate caustic treatment vessel for aldehyde removal provides increased contact time between the acetone product and the alkaline solution, providing higher aldehyde removal.

Description

Field of the invention

[0001] The present application relates to methods and systems for the manufacture of acetone from cumene. More specifically, embodiments relate to improving the purity of acetone manufactured.

[0002] INTRODUCTION

[0003] Phenol and acetone are manufactured in various processes, with the most common process variously known as the Hock process, the Hock and Lang process, or the cumene to phenol process, among others. This process begins with the oxidation of cumene (isopropylbenzene) to form cumene hydroperoxide (CHP). The CHP is then cleaved in the presence of an acid catalyst to form a mixture of phenol, acetone, and / or alpha-methylstyrene ("AMS"). The mixture is subsequently neutralized and fractionated to recover the end products phenol, acetone, and / or AMS.

[0004] While this process has been used for decades, there remains a need to optimize the purity of the aldehyde manufactured.

[0005] SUMMARY

[0006] Disclosed herein are methods of purifying acetone in an acetone manufacturing process, the method comprising: feeding a crude acetone fraction to a first feed point in an acetone purification column (APC), removing a portion of the crude acetone fraction from the APC via a first side draw of the APC located above the first feed point, feeding the removed portion of the crude acetone fraction to a caustic treatment vessel, feeding an aqueous base solution to the caustic treatment vessel, returning a bottoms stream from the caustic treatment vessel to the APC via a second feed point, wherein the second feed point is located between the first feed point and the first side draw, and obtaining purified acetone from a second side draw located above the first side draw. According to some embodiments, the crude acetone fraction is obtained as an overhead stream from a crude acetone column (CAC) upstream from the APC. According to some embodiments, the crude acetone fraction comprises acetone, water, cumene, alpha-methylstyrene (AMS), phenol, methanol, and aldehydes. According to some embodiments, the crude acetone fraction comprises 60 to 1000 ppm (volume) of aldehydes, and wherein the aldehydes comprise acetaldehyde and / or propionaldehyde. According to some embodiments, the crude acetone fraction comprises 50 to 500 ppm (volume) of methanol. According to some embodiments, the aqueous base solution comprises an alkali metal oxide, hydroxide, or phenate, or an alkaline earth metal oxide, hydroxide, or phenate. According to some embodiments, the aqueous base solution comprises sodium hydroxide. According to some embodiments, the sodium hydroxide has a concentration of about 0.1 to about 15%. According to some embodiments, the caustic treatment vessel has a temperature of about 45 to about 75 °C. According to some embodiments, the caustic treatment vessel does not include internal components. According to some embodiments, the caustic treatment vessel includes static mixing internal components. According to some embodiments, the caustic treatment vessel includes an agitator. According to some embodiments, the caustic treatment vessel includes a circulation pump. According to some embodiments, the caustic treatment vessel provides a residence time of about 3 to about 60 minutes. According to some embodiments, the method further comprises contacting the removed portion of the crude acetone fraction with a zeolite adsorbent to remove methanol from the removed portion of the crude acetone fraction prior to feeding the removed portion of the crude acetone fraction to the caustic treatment vessel. According to some embodiments, the purified acetone comprises less than about 20 ppm wt of total aldehydes. According to some embodiments, the purified acetone has a permanganate time of greater than 12 hours. According to some embodiments, the purified acetone has a methanol content of less than 100 ppm (weight).

[0007] Also disclosed herein is a system for recovering purified acetone, the system comprising: a crude acetone column (CAC) configured to separate the product of a cumene hydroperoxide cleavage reaction into a top fraction comprising crude acetone and a bottom fraction comprising phenol, an acetone purification column (APC) configured to: receive crude acetone at a first feed point in the APC, separate the crude acetone into purified acetone and residual heavy compounds, and provide the purified acetone at a first side draw located above the first feed point, and a caustic treatment vessel configured to: receive a portion of the crude acetone drawn from a second side draw of the APC located above the first feed point of the APC and below the first side draw, receive a feed of an aqueous alkaline solution, mix the portion of the crude acetone and the aqueous alkaline solution, and return the contents of the caustic treatment vessel to a second feed point of the APC, wherein the second feed point is located between the first feed point and the second side draw. According to some embodiments, the crude acetone fraction comprises acetone, water, cumene, alpha-methylstyrene (AMS), phenol, methanol, and aldehydes. According to some embodiments, the aqueous alkaline solution comprises sodium hydroxide. According to some embodiments, the caustic treatment vessel provides a residence time of about 3 to about 60 minutes. According to some embodiments, the caustic treatment vessel is free of any internal components. According to some embodiments, the caustic treatment vessel comprises one or more of a static mixing internal component, an agitator, or a circulation pump. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 Embodiments of a system for manufacturing acetone and phenol from cumene hydroperoxide (CHP) are shown.

[0010] Figure 2 Embodiments of an improved system for purifying acetone are shown, wherein a portion of the manufactured acetone is reacted with a caustic substance within a caustic reaction vessel.

[0011] Figure 3 Embodiments of an improved system for purifying acetone are shown, wherein a portion of the manufactured acetone is transported through an adsorbent vessel to remove alkyl alcohols from the manufactured acetone.

[0012] Figure 4 Further embodiments of an improved system for purifying acetone are shown, wherein a portion of the manufactured acetone is transported through an adsorbent vessel to remove alkyl alcohols from the manufactured acetone.

[0013] DETAILED DESCRIPTION

[0014] Figure 1A system 100 for manufacturing acetone and phenol from cumene hydroperoxide (CHP) is shown. It will be understood that aspects and equipment of the system 100 (and other systems described in this disclosure) that are not specifically relevant to the present disclosure are not mentioned here but are implemented in the practical operation of such systems. Such aspects and equipment are known in the art and can be described in the references incorporated above.

[0015] Concentrated CHP enters the system via line 102. The concentration of CHP in line 102 can be about 65 to 90 wt.%, and more generally about 80 to 85 wt.%, for example to about 82 wt.%. The CHP can be manufactured by oxidation of cumene, for example, as described in U.S. Patent No. 8,697,917, the entire contents of which are incorporated herein by reference. Oxidation products (not shown) from the oxidation of cumene include CHP and can also include one or more of alpha-methylstyrene (AMS), dimethylbenzyl alcohol (DMBA), and / or acetophenone (ACP).

[0016] The concentrated CHP is provided to one or two cracking reactors in series, for example, as described in U.S. Patent No. 5,371,305. In the illustrated system 100, two cracking reactors in series are shown. The CHP is provided to a first cracking reactor 104, where it undergoes acid catalyzed cracking. For example, the acid catalyst can be sulfuric acid (H2SO4). In the illustrated embodiment, the first cracking reactor can be, for example, a back-mixed reactor and operates at 50°C to 80°C. In the first cracking reactor, the CHP reacts in two reaction portions, i) the CHP cracks to form phenol and acetone, and ii) the CHP partially reacts with DMBA in an equilibrium reaction to give the intermediate product dicumyl peroxide (DCP) and water. The DMBA partially dehydrates to AMS, which reacts with phenol in a consecutive reaction to high-boiling cumyl phenol, and AMS can also form high-boiling dimers. Additional byproducts such as hydroxyacetone (HA), 2-methylbenzofuran (2-MBF), and isopropylidene acetone (MO) can also be produced. The cracking reaction is highly exothermic, so recycled acetone can be provided to the cracking reactor(s) to maintain proper dilution, thereby minimizing the formation of undesirable byproducts. In the illustrated embodiment, recycled product acetone is provided to the first cracking reactor via line 106. Water can also be added for optimal cracking yield.

[0017] In the illustrated embodiment, the product of the first cleavage reactor 104 is fed to a second cleavage reactor 108, in which three main reactions occur: i) residual CHP from the first cleavage reactor cleaves to phenol and acetone, ii) residual DMBA from the first cleavage reactor dehydrates to AMS, and iii) DCP converts to AMS, phenol, and acetone. The second stage cleavage reactor can be, for example, a plug flow reactor at a temperature of about 105°C to 145°C and can be steam heated.

[0018] In the illustrated system 100, a cooler 110 is used to cool the cleavage product from the second cleavage reactor 108 and direct it to one or more neutralization and scrubbing units 112. The cleavage effluent contains sulfuric acid, which is used as a catalyst for the cleavage reactions. To avoid corrosion problems in downstream equipment, one or more bases such as sodium hydroxide and / or one or more salt solutions must be used to extract and neutralize the acid. For example, the salt solution can be or include sodium phenoxide. The salt solution can reduce or stop any ongoing cleavage reactions in the cleavage product. Thus, the neutralization and scrubbing unit(s) 112 can produce a neutralized cleavage product.

[0019] The steps following cleavage and neutralization, namely the acetone fractionation, are primarily directed at purification of the products (acetone and phenol) and recovery of the by-products and recyclable cumene. The acetone fractionation system serves the purposes of (1) a crude separation of light and heavy materials in the feed and (2) purification of the acetone product. The organic effluent from the neutralization unit(s) 112 flows via line 113 into a first distillation column. The first distillation column is referred to herein as the crude acetone column (CAC) 114. The function of the CAC is to separate the neutralization product into a phenol fraction and an acetone fraction. Various aspects of the CAC are described in U.S. Patent No. 8,889,915, the entirety of which is incorporated herein by reference. The vapor distillate (line 120) contains acetone, water, cumene, AMS, a small amount of phenol, and other light materials in the feed. The CAC can be equipped with a CAC reboiler 116 and a CAC condenser 118. The CAC reboiler 116 can be, for example, a forced circulation type exchanger heated by high pressure steam. The phenol-rich bottoms (line 122) can be directed to a phenol fractionation unit (not shown). The overhead vapor (line 120) is partially condensed in the CAC condenser 118. The condensed liquid is returned to the CAC 114, while the vapor distillate is sent via line 126 to a second distillation column, referred to herein as the acetone product column or acetone purification column (APC) 124. According to some embodiments, the vapor distillate provided to the APC 124 via line 126 can include about 7 to about 12 volume percent cumene, about 0.1 to about 0.2 volume percent phenol, about 40 to about 50 volume percent acetone, about 1 to about 2 volume percent AMS, about 200 to about 500 ppm (volume) methanol, and about 100 to about 1000 ppm (volume) total aldehydes.

[0020] The purpose of the APC 124 is to remove light ends (primarily acetaldehyde) from the acetone product via line 128, and to separate the acetone from water, cumene, AMS, and other heavy organics. Various aspects of the APC are described in U.S. Patent No. 4,340,447 (the ‘447 patent), the contents of which are incorporated by reference. The APC is equipped with an APC reboiler 130 and an APC condenser 131. The APC reboiler 130 can be fed from a liquid trap outside the bottom tray of the APC 124 and a recycle stream from the column bottom, and can be heated by low pressure steam.

[0021] The internal volume 140 of the APC 124 can be empty, partially filled with one or more packing materials, or completely filled with one or more packing materials (not shown). Exemplary packing materials can include, but are not limited to, trays, packings, or combinations thereof. As used herein, the term "tray" can include, but is not limited to, one or more types of trays that can improve contact between the gas and liquid phases within the APC 124. Exemplary trays can include, but are not limited to, perforated trays, sieve trays, bubble cap trays, float valve trays, fixed valve trays, cylinder trays, dual flow trays, baffle trays, spray tray, chimney trays, slit trays, or any combination thereof. As used herein, the term "packing material" or "packing" can include, but is not limited to, one or more types of structured and / or random shaped materials disposed within the APC 124. The packing material can increase the effective surface area in the APC 124, which can improve mass transfer between the liquid and gas phases in the APC 124. The packing material can be made of any suitable material, such as metals, non-metals, polymers, ceramics, glasses, or any combination thereof. Exemplary examples of random packing materials can include, but are not limited to, Raschig rings, NeXRing TM , Nutter Rings TM , I-Rings TM , C-Rings TM , P-Rings TM , R-Rings TM , and ULTRA, CASCADE MINI AHPP Saddle-Rings, Pall rings, SuperBlend TM 2-Pac, or any combination thereof. Exemplary examples of commercially available structured packings can include, but are not limited to, structured packings, corrugated sheets, crimped sheets, mesh, lattices, wire mesh, or any combination thereof. The packing material can improve mass transfer and / or separation of the multi-component fluid. The packing material and / or packing pattern in the internal volume 140 can include one or more structured and / or random packing materials. Two or more types of packing materials can be disposed within the internal volume 126. The APC 124 can be made of one or more metallic materials that are physically and chemically compatible with the temperature, pressure, and contents of the APC 124. Suitable metallic materials can include, but are not limited to, ferrous alloys including carbon steel and stainless steel such as cladded carbon steel and 304 and 316 stainless steel, as well as duplex stainless steels, and combinations of these metallic materials. Further, the APC 124 can operate at pressure temperatures ranging from a low value of about 40 kPa, about 50 kPa, or about 60 kPa, to a high value of about 80 kPa, about 90 kPa, or about 100 kPa.

[0022] The net bottoms stream 132 from the APC 124 can be fed to a crude AMS section (not shown). Product acetone can be obtained from a side draw 134. A portion of the APC 124 reflux can be recycled to the cracking reactor section via line 106, for example, to the first cracking reactor 104 as mentioned above. The amount of recycled acetone can be determined as a ratio based on the CHP to cracking reactor feed. For example, the amount of acetone recycled to the cracking reactor(s) can be about 0.1 to about 0.5 wt% based on the CHP to cracking reactor feed.

[0023] The APC 124 is provided with a caustic addition point 136 for the addition of a caustic material. The caustic material can be, for example, an alkali metal oxide, hydroxide, or phenate or an alkaline earth metal oxide, hydroxide, or phenate. One example of a suitable caustic material is sodium hydroxide. The caustic addition point 136 is provided between the feed stream 126 and the product side draw 134. The caustic is added to the APC 124 to reduce the amount of aldehydes in the acetone product. The aldehydes form heavier ketones via a hydroxy aldehyde condensation reaction in the presence of the caustic, thereby purifying the acetone product. The use of caustic in the APC 124 to reduce the amount of aldehydes in the acetone product is described in the incorporated '447 patent.

[0024] As is known in the art, one test for determining the purity of an acetone product is the permanganate time (PMT) test, which involves adding a small amount of potassium permanganate to a sample of acetone and determining the time required for the color to dissipate. The longer the color dissipates, the lower the content of reducing species such as aldehydes in the sample and the higher the quality of the acetone. The process described in the '477 patent can produce acetone having a PMT of about 4 hours, which corresponds to about 60 to about 120 ppm (volume) of total aldehyde impurities.

[0025] As shown in Figure 1 In the embodiment shown in

[0026] The inventors have recognized that the use of a system 200 as shown in Figure 2 may improve the contact time of the aldehydes with the caustic. In Figure 2 like reference numbers designate the same components as in the system 100 shown in Figure 1 . Figure 2The CAC 114 and the APC 124 are shown, which are similar to the respective devices of system 100 Figure 1 . System 200 also includes the upstream equipment shown in system 100 Figure 1 , i.e., the cleavage reactor (104, 108), the cooler (110), and the neutralization and washing unit (112), but for clarity, the upstream equipment is omitted from system 200 Figure 2 . As in system 100 Figure 1 , in system 200 Figure 2 , the organic effluent from the neutralization unit(s) flows via line 113 into the CAC 114. The vapor distillate from the CAC, referred to herein as the "crude acetone fraction," is provided via line 126 to the APC 124 and the phenol-rich bottoms from the CAC exit via line 122. According to some embodiments, the crude acetone fraction provided to the APC 124 via line 126 can include about 12 vol% cumene, about 0.1 to about 0.2 vol% phenol, about 40 to about 50 vol% acetone, about 1 to about 2 vol% AMS, about 50 to about 500 ppm (by volume) of methanol, and about 60 to about 1000 ppm (by volume) of total aldehydes. More particularly, the crude acetone fraction can include about 60 to 1000 ppm (by volume) of aldehydes, where the aldehydes include acetaldehyde and / or propionaldehyde.

[0027] The internal volume 140 of the APC 124 of system 200 is as described above. The APC 124 of system 200 is equipped with a side draw 202 from which a portion of the material within the column can be obtained and provided to a caustic treatment vessel 204. The side draw can be configured at any point on the APC 124, but according to most embodiments, it is configured between the inlet line 126 from the CAC and the acetone product line 134, as shown in Figure 2 . A caustic material is provided to the caustic treatment vessel 204 via line 206. As in system 100 Figure 1 , the caustic material can be, for example, an alkali metal oxide, hydroxide, or phenate or an alkaline earth metal oxide, hydroxide, or phenate. One example of a suitable caustic material is sodium hydroxide. The bottoms stream from the caustic treatment vessel 204 is returned to the APC 124 via line 208, which is generally configured to feed into the APC at a location between line 126 and line 134.

[0028] By removing a portion of the material from the APC and reacting it with the caustic material in the caustic treatment vessel 204 before returning the contents of the caustic treatment vessel to the APC, the contact time with the caustic material is increased. As in system 100 Figure 1) compared to the prior art. This results in more efficient removal of aldehydes from the acetone product. The system 200 is also capable of handling higher aldehyde levels in the crude vapor acetone feed (i.e., the feed to the APC via line 126). High levels of aldehydes can be due to: 1) high impurities in the cumene feedstock entering the unit, and / or 2) the presence of a recycle acetone stream from other process units downstream of the phenol unit that use acetone. In the system 200, the caustic treated stream (i.e., stream 202) is free of phenol and has low levels of other organic impurities such as cumene and AMS.

[0029] The caustic treatment vessel 204 can be, for example, a vessel without internal components. According to some embodiments, mixing can be provided in the caustic treatment vessel 204 as the combined stream is in two liquid phases. That is, stream 202 is an organic phase comprising primarily acetone, cumene, and AMS, and stream 206 is an aqueous phase. Mixing can be accomplished, for example, using static mixing type internal components installed inside the vessel, agitators installed with the vessel, and / or circulating pumps that promote mixing and contact of the two phases. According to some embodiments, the residence time of the contents in the caustic treatment vessel can be from about 3 to about 60 minutes, for example, from about 5 to 30 minutes.

[0030] According to some embodiments, the caustic concentration in the caustic treatment vessel 204 can be from about 0.1 to about 15% caustic. According to some embodiments, the temperature within the caustic treatment vessel is from about 45 to about 75 °C, for example, from 50 to 65 °C. According to some embodiments, the temperature within the caustic treatment vessel is maintained by heat from the material being passed from the APC, and no additional heating is required. Alternatively, additional heat can be provided to the caustic treatment vessel, for example, by steam heating.

[0031] As mentioned above, the caustic treated stream is returned to the APC via line 208, which can enter the APC just above, for example, the vapor feed line 126. Due to the presence of free caustic in the caustic feed from the caustic treatment vessel, phenol in the APC is converted to sodium phenoxide. Residual aldehydes are also converted to heavier ketones on the trays of the APC along with the phenol / sodium phenoxide reaction. Other heavier organic impurities such as cumene and AMS are removed from the acetone as the vapor travels up the column.

[0032] The inventors have discovered that the disclosed methods and systems, such as system 200, can produce acetone having a total aldehyde content of about 5 to about 40 ppm (wt). According to some embodiments, the aldehyde content is less than 40 ppm (wt), less than 20 ppm (wt), or less than 10 ppm (wt). The resulting acetone can achieve a permanganate time of about 12 to about 24 hours, which is a significant improvement over prior art systems. For example, according to some embodiments, the permanganate time is greater than 12 hours, greater than 18 hours, or greater than 24 hours.

[0033] Figure 3 and 4 Further embodiments are shown for purifying acetone in APC. In Figure 3 and 4 , only the APC and associated equipment are shown. It should be understood that systems 300 Figure 3 ) and 400 Figure 4 ) each include the upstream equipment shown in Figure 1 and 2 , but for clarity, the equipment is omitted from Figure 3 and 4 . In Figure 3 and 4 , like numerals refer to the same components as the systems 100 and 299 shown in Figure 1 and 2 , respectively.

[0034] As shown in Figure 3 and 4 , the inventors have realized that the acetone purified in the APC 140 can be further purified to remove alkyl alcohols, such as methanol, by passing a portion of the APC contents through an adsorbent, such as a zeolite, for example a molecular sieve material. With reference to Figure 3 , the APC 140 is equipped with a first side draw 202 that passes a portion of the APC contents to a caustic treatment vessel 204, as in system 200 Figure 2 . The APC 140 is also equipped with a further side draw 302 that passes a portion of the APC contents to an adsorbent vessel 304 configured to contain an adsorbent, such as a zeolite molecular sieve material. Examples of suitable zeolite molecular sieve materials include molecular sieves having a pore size of about 4 to about 5 Angstroms. The contents from the adsorbent vessel 304 are then provided to the caustic treatment vessel 204 via line 306. As described above, aldehydes are removed in the caustic treatment vessel 204. The effluent stream from the caustic treatment vessel is returned to the APC 140 via line 208, as described above for system 200 Figure 2 .

[0035] Figure 4An alternative embodiment of system 400 is shown having an APC 140 equipped with an adsorbent vessel 304 containing an adsorbent such as a molecular sieve material for removing alkyl alcohol from acetone. System 400 differs from system 300 ( Figure 3 ) in that all of the APC contents delivered from APC 140 to caustic treatment vessel 204 are passed through adsorbent vessel 304. In other words, a portion of the APC contents is directed via line 302 to adsorbent vessel 304. The contents of adsorbent vessel 304 are then directed via line 306 to caustic treatment vessel 204. There is no other side draw, such as side draw 202 ( Figure 3 ) for providing the contents of the APC directly to caustic treatment vessel 204. In other respects, systems 300 ( Figure 3 ) and 400 are identical. The inventors have discovered that systems such as system 300 ( Figure 3 ) and system 400 ( Figure 4 ) can produce acetone having an aldehyde content of less than 20 ppm by weight or less than 10 ppm by weight; a permanganate time of greater than 12 hours, greater than 18 hours or greater than 24 hours, and a methanol content of less than 100 ppm by weight or less than 50 ppm by weight.

[0036] While particular embodiments of the present application have been shown and described, it will be understood that the above discussion is not intended to limit the present application to these embodiments. It will be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present application. It is therefore intended that the present application cover all alternatives, modifications and equivalents that can fall within the spirit and scope of the present application as defined by the claims.

Claims

1. A method of purifying acetone in an acetone manufacturing process, the method comprising: feeding a crude acetone fraction to a first feed point in an acetone purification column APC, removing a portion of the crude acetone fraction from the APC via a first side draw of the APC located above the first feed point, feeding the removed portion of the crude acetone fraction to a caustic treatment vessel, feeding a basic aqueous solution to the caustic treatment vessel, returning a bottoms stream from the caustic treatment vessel to the APC via a second feed point, wherein the second feed point is located between the first feed point and the first side draw, and obtaining purified acetone from a second side draw located above the first side draw.

2. The method of claim 1, wherein the crude acetone fraction is obtained as an overhead stream from a crude acetone column CAC upstream of the APC.

3. The method of claim 1, wherein the crude acetone fraction comprises acetone, water, cumene, alpha-methylstyrene, phenol, methanol, and aldehydes.

4. The method of claim 1, wherein the crude acetone fraction comprises 60 to 1000 ppm (volume) of aldehydes, and wherein the aldehydes comprise acetaldehyde and / or propionaldehyde.

5. The method of claim 1, wherein the crude acetone fraction comprises 50 to 500 ppm (volume) of methanol.

6. The method of claim 1, wherein the basic aqueous solution comprises an alkali metal oxide, hydroxide, or phenate or an alkaline earth metal oxide, hydroxide, or phenate.

7. The method of claim 4, wherein the basic aqueous solution comprises sodium hydroxide.

8. The method of claim 7, wherein the sodium hydroxide has a concentration of 0.1 to 15%.

9. The method of claim 1, wherein the caustic treatment vessel has a temperature of 45 to 75 °C.

10. The method of claim 1, wherein the caustic treatment vessel does not include internal components.

11. The method of claim 1, wherein the caustic treatment vessel includes static mixing internal components.

12. The method of claim 1, wherein the caustic treatment vessel includes an agitator.

13. The method of claim 1, wherein the caustic treatment vessel includes a recirculation pump.

14. The method of claim 1, wherein the caustic treatment vessel provides a residence time of 3 to 60 minutes.

15. The method of claim 1, further comprising contacting the removed portion of the crude acetone fraction with a zeolite adsorbent to remove methanol from the removed portion of the crude acetone fraction prior to feeding the removed portion of the crude acetone fraction to the caustic treatment vessel.

16. The method of claim 1, wherein the purified acetone comprises less than 20 ppmwt of total aldehydes.

17. The method of claim 1, wherein the purified acetone has a permanganate time of greater than 12 hours.

18. The method of claim 1, wherein the purified acetone has a methanol content of less than 100 ppm (weight).

19. A system for recovering purified acetone, the system comprising: a crude acetone column CAC configured to separate the product of the cumene hydroperoxide cleavage reaction into a top fraction comprising crude acetone and a bottom fraction comprising phenol, an acetone purification column APC configured to: receive crude acetone at a first feed point in the APC, separate the crude acetone into purified acetone and residual heavy compounds, and provide purified acetone at a first side draw located above the first feed point, and a caustic treatment vessel configured to: receive a portion of the crude acetone drawn from a second side draw of the APC located above the first feed point of the APC and below the first side draw, receive a feed of an aqueous alkaline solution, mix the portion of the crude acetone and the aqueous alkaline solution, and return the contents of the caustic treatment vessel to a second feed point of the APC, wherein the second feed point is located between the first feed point and the second side draw.

20. The system of claim 19, wherein the crude acetone fraction comprises acetone, water, cumene, a-methylstyrene, phenol, methanol, and aldehydes.

21. The system of claim 19, wherein the aqueous alkaline solution comprises sodium hydroxide.

22. The system of claim 19, wherein the caustic treatment vessel provides a residence time of 3 to 60 minutes.

23. The system of claim 19, wherein the caustic treatment vessel is free of any internal components.

24. The system of claim 19, wherein the caustic treatment vessel includes one or more of static mixing internal components, an agitator, or a circulation pump.

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