Title of Invention	"A PROCESS FOR THE PRODUCTION OF PHENEL HAVING A REDUCED LEVEL OF METHYL BENZOFORAN"
Abstract	A process for the reduction of methylbenzofuran (MBF) impurities in phenol obtained from the decomposition product of cumene hydroperoxide requires treating the phenol to reduce the level of acetol, contacting the phenol containing a low levelof acetol with an acid resin at sufficient temperature and residence time to reduce the level of MBF by conversion to higher boiling compounds, then distilling the phenol to separate phenol from higher boiling compounds. The phenol may be treated in known ways, such as by treatment with an amine, to reduce the level of acetol. The phenol containing a low level of acetol is contacted with a strong acid resin to reduce the level of MBF.

Title of Invention

"A PROCESS FOR THE PRODUCTION OF PHENEL HAVING A REDUCED LEVEL OF METHYL BENZOFORAN"

Abstract

A process for the reduction of methylbenzofuran (MBF) impurities in phenol obtained from the decomposition product of cumene hydroperoxide requires treating the phenol to reduce the level of acetol, contacting the phenol containing a low levelof acetol with an acid resin at sufficient temperature and residence time to reduce the level of MBF by conversion to higher boiling compounds, then distilling the phenol to separate phenol from higher boiling compounds. The phenol may be treated in known ways, such as by treatment with an amine, to reduce the level of acetol. The phenol containing a low level of acetol is contacted with a strong acid resin to reduce the level of MBF.

Full Text	BACKGROUND OF THE INVENTION 1. Field of the invention. This invention relates to the production of high purity phenol, particularly to a process for reduction of levels of methylbenzofuran in phenol to obtain desired high purity. 2. Description of related art. Phenol may be produced from cumene by the oxidation of cumene to cumene hydroperoxide, followed by cleavage or decomposition of the hydroperoxide to phenol and acetone. The reaction product is introduced into a separation and recovery system wherein acetone is separated from remaining product by distillation. The remaining product is then further distilled to separate cumene. The cumene recovery column can be operated if desired to recover alpha-methylstyrene (AMS) with the cumene, or the product remaining from the cumene recovery column may be introduced into a crude AMS column to separate AMS from the remaining product. The remaining product is introduced into a phenol recovery column to separate phenol from remaining higher boiling constituents. The phenol product obtained by fractional distillation includes many impurities including AMS, acetol (hydroxyacetone), acetophenone, cumylphenols and 2- and 3-methylbenzofuran (collectively or individually MBF). For certain purposes it is important to reduce such impurities to avoid problems with discoloration on aging or on sulfonation or on chlorination. Since MBF and phenol have similar volatility, MBF cannot be separated effectively by fractional distillation. Distillation in the presence of water, or steam stripping, has been disclosed in U. S. Patents 5,064,507 and 4,857,151 to reduce the amount of MBF. Such steam stripping requires substantial expenditure of energy to produce the necessary amount of steam and the use of large distillation columns to accommodate the flow of the organic vapors and the added steam. Thus removal of MBF by steam stripping is expensive in terms of operating cost and capital investment. U. S. Patent 3,810,946 discloses reduction of MBF impurities by heating phenol with hydrobromic or hydroiodic acid. Treatment with halogenated compounds, however, leads to problems with corrosion which adds substantially to the cost of materials of construction. The need exists for an effective and economical process to reduce the level of MBF in phenol to obtain desired high purity phenol. SUMMARY OF THE INVENTION A process for the reduction of methylbenzofuran (MBF) impurities in phenol obtained from the decomposition product of cumene hydroperoxide requires treating the phenol to reduce the level of acetol, contacting the phenol containing a low level of acetol with an acid resin at sufficient temperature and residence time to reduce the level of MBF by conversion to higher boiling compounds, then distilling the phenol to separate phenol from higher boiling compounds. The phenol may be treated in known ways, such as by treatment with an amine, to reduce the level of acetol. The phenol containing a low level of acetol is contacted with a strong acid resin to reduce the level of MBF. Thus according to the present invention there is provided a process for the production of phenol having a reduced level of methylbenzofuran, the process comprising the steps of: treating the phenol of the kind such as herein described in a conventional manner to reduce the level of acetol to an amount not exceeding 260 ppm; contacting the phenol so produced with an aromatic sulfonic acid resin or a solid super acid catalyst compound at a temperature in the range of from 70°C to 120°C at a rate of from 1 to 10 bed volumes per hour to reduce the level of methylbenzofuran by conversion to higher boiling compounds; then distilling the phenol so produced to separate the phenol from the higher boiling compounds. BEST MODE FOR CARRYING OUT THE INVENTION The phenol product which can be purified in accordance with the method of the present invention has been obtained by decomposition of cumene hydroperoxide to form phenol and acetone as principal products, followed by distillation to remove the acetone which has a lower boiling point than phenol. We have now found that 2- and 3-methylbenzofuran (collectively or individually MBF) can be effectively and economically removed from phenol by treatment with an aromatic sulfonic acid resin or a solid superacid catalyst compound at moderate temperatures provided that acetol (hydroxyacetone), another phenol impurity, is absent or present in the phenol at low levels, for example in an amount not to exceed 260 ppm, preferably not to exceed 200 ppm, more preferably not to exceed 100 ppm, most preferably not to exceed 5 ppm. At higher concentrations of acetol, the effect of resin treatment decreases and becomes progressively less economically attractive. Strong acid resins useful for this invention contain aromatic sulfonic acid groups and typically consist of granules of sulfonated crosslinked polystyrene. Such aromatic sulfonic acid resins are available commercially, for example Amberlyst® 15 resin, a bead form sulfonic acid cation exchange resin available from Rohm and Haas. Additionally, solid superacid catalyst systems may be used. These systems have been developed as alternatives to liquid acid systems such as hydrofluoric acid used for petroleum acylation operations. Some are obtained from existing systems (AICI3, SbF5, SO42- on a supporting substrate of Zr02 or Ti02) by attaching existing strong acid constituents to oxide or salt substrates to immobilize the acid activity. Others are more novel heteropolyacids made from metal oxide clusters (tungsten and molybdenum). Representative catalysts are discussed in "Solid Superacid Catalysts," Makoto Misuno and Toshio Okuhara, Chemtech. November 1993. Solid-superacid catalyst compounds are defined herein as those acid compounds wifli acid strength greater than that of 100% H2SO4. The effectiveness of the treatment with resin increases with increasing temperature within the range of stability of the resin itself, for example within the range of 70 to 120° C, more preferably 80 to 110° C. Higher contact times are also more effective but increase the cost of the treatment. The contact of the phenol with the acid resin can be accomplished in known ways, such as by stirring the resin beads with the phenol, or by passing the phenol through a bed of acid resin, which may be the preferred commercial alternative. The effectiveness of temperature and contact time are demonstrated in the following examples. See example 1 for a definition of the unit of bed volume/hour, which for this invention is preferred to be 1 to 10, more preferably 2 to 6 bed volume/hour. In these examples analysis of 2-MBF was by conventional gas chromatography when present in concentrations of 1 ppm or greater. Below that concentration, liquid chromatography was performed using a non-polar, octadecylsilane column and a UV detector set at a wave length of 254 nm. Methanol/water was used as the eluent at ambient temperature at the constant composition of 90/10 by volume. Calculations of 2-MBF concentrations were based on comparisons of peak areas to calibration standards. Example 1 Phenol containing less than 1 ppm acetol and amounts of MBF as indicated in Table 1 under "inlet" was passed through a bed of acid resin (Amberlyst 15) at the rates and temperature indicated. Bed volume is a volume of phenol corresponding to the volume of the resin bed used. The unit bed volume/hour is inversely proportional to contact time. The results of analyses on outlet samples show that the treatment is more effective at higher temperature and lower bed volume/hr values (higher contact times). The results also show that MBF levels can be reduced to less than 0.1 ppm. Example 2 Phenol containing amounts of acetol and MBF as indicated under "inlet" in Table II was passed through a bed of acid resin (Amberlyst 15) at 4.0 bed volumes/hr. Samples were taken after the resin bed and analyzed. The results show that although acetol was removed by the treatment, to levels of less than 1 ppm, MBF could not be lowered to less than 4 ppm. Example 3 Phenol containing 20 ppm MBF and amounts of acetol of less than 1,200, and 500 ppm, respectively was passed through a bed of acid resin (Amberlyst 15) at 4 bed volumes/hour at different temperatures as shown on Table III. Samples were taken after the resin bed and analyzed. The results show that acetol hampers removal of MBF by the treatment and does so to a greater extent at higher temperatures. At 500 ppm acetol level and 110°C there was no removal of MBF TABLE 1 Effect of temperature and contact time on removal of MBF from phenol containing less than 1 ppm acetol. 2 Bed Volumes/hr. 4 Bed Volumes/hr. 6 Bed Volumes/hr. T (°C) Inlet/Outlet Inlet/Outlet Inlet/Outlet 65 20ppm/ 80 16/ 95 17/ 110 17/ TABLE II Effect of acetol concentration on removal of MBF from phenol by acid resin at 4 bed volumes/hr. MBF Acetol T (°C) Bed Inlet/Outlet Inlet/Outlet 80 20/4 ppm 250/ 95 18/5 260/ 95 18/5 250/ 110 22/8 250/ 116 25/11 260/ 95 20/10 500/ 110 25/25 500/ TABLE III Effect of temperature and acetol level on MBF removal from phenol by acid resin at 4 bed volumes/hr. Acetol at Bed Inlet MBF at Outlet Temperature 80°C 90°C 110°C 200 45 8 500 Not run 10 25 We Claims: 1. A process for the production of phenol having a reduced level of methylbenzofuran, the process comprising the steps of: treating the phenol of the kind such as herein described in a conventional manner to reduce the level of acetol to an amount not exceeding 260 ppm; contacting the phenol so produced with an aromatic sulfonic acid resin or a solid super acid catalyst compound at a temperature in the range of from 70°C to 120°C at a rate of from 1 to 10 bed volumes per hour to reduce the level of methylbenzofuran by conversion to higher boiling compounds; then distilling the phenol so produced to separate the phenol from the higher boiling compounds. 2.. The process as claimed in claim 1, wherein the step of treating the phenol to reduce the level of acetol comprises treating the phenol with an amine. 3- The process as claimed in claim 1, wherein the step of treating the phenol to reduce the level of acetol comprises treating the phenol with an amine to reduce the level of acetol to an amount not to exceed 5 ppm, and the phenol so produced is contacted with an aromatic sulfonic acid resin in a resin bed at a temperature in the range of from 90° C to 110° C at a rate of from 2 to 6 bed volumes per hour. 4. A process for the production of phenol having a reduced level of methylbenzofuran substantially as hereinbefore described with reference to the foregoing examples.

Full Text

BACKGROUND OF THE INVENTION
1. Field of the invention. This invention relates to the production of high purity phenol, particularly to a process for reduction of levels of methylbenzofuran in phenol to obtain desired high purity.
2. Description of related art. Phenol may be produced from cumene by the oxidation of cumene to cumene hydroperoxide, followed by cleavage or decomposition of the hydroperoxide to phenol and acetone. The reaction product is introduced into a separation and recovery system wherein acetone is separated from remaining product by distillation. The remaining product is then further distilled to separate cumene. The cumene recovery column can be operated if desired to recover alpha-methylstyrene (AMS) with the cumene, or the product remaining from the cumene recovery column may be introduced into a crude AMS column to separate AMS from the remaining product. The remaining product is introduced into a phenol recovery column to separate phenol from remaining higher boiling constituents.
The phenol product obtained by fractional distillation includes many impurities including AMS, acetol (hydroxyacetone), acetophenone, cumylphenols and 2- and 3-methylbenzofuran (collectively or individually MBF). For certain purposes it is important to reduce such impurities to avoid problems with discoloration on aging or on sulfonation or on chlorination. Since MBF and phenol have similar volatility, MBF cannot be separated effectively by fractional distillation. Distillation in the presence of water, or steam stripping, has been disclosed in U. S. Patents 5,064,507 and 4,857,151 to reduce the amount of MBF. Such steam stripping requires substantial expenditure of energy to produce the necessary amount of steam and the use of large distillation columns to accommodate the flow of the organic vapors and the added steam. Thus removal of MBF by steam stripping is expensive in terms of operating cost and capital investment. U. S. Patent 3,810,946 discloses reduction of MBF impurities by heating phenol with hydrobromic or hydroiodic acid. Treatment with halogenated compounds, however, leads to problems with corrosion which adds substantially to the cost of materials of construction.
The need exists for an effective and economical process to reduce the level of MBF in phenol to obtain desired high purity phenol.
SUMMARY OF THE INVENTION
A process for the reduction of methylbenzofuran (MBF) impurities in phenol obtained from the decomposition product of cumene hydroperoxide requires treating the phenol to reduce the level of acetol, contacting the phenol containing a low level of acetol with an acid resin at sufficient temperature and residence time to reduce the level of MBF by conversion to higher boiling compounds, then distilling the phenol to separate phenol from higher boiling compounds. The phenol may be treated in known ways, such as by treatment with an amine, to reduce the level of acetol. The phenol containing a low level of acetol is contacted with a strong acid resin to reduce the level of MBF.
Thus according to the present invention there is provided a process for the production of phenol having a reduced level of methylbenzofuran, the process comprising the steps of:
treating the phenol of the kind such as herein described in a conventional manner to reduce the level of acetol to an amount not exceeding 260 ppm;
contacting the phenol so produced with an aromatic sulfonic acid resin or a solid super acid catalyst compound at a temperature in the range of from 70°C to 120°C at a rate of from 1 to 10 bed volumes per hour to reduce the level of methylbenzofuran by conversion to higher boiling compounds; then
distilling the phenol so produced to separate the phenol from the higher boiling compounds.
BEST MODE FOR CARRYING OUT THE INVENTION
The phenol product which can be purified in accordance with the method of the present invention has been obtained by decomposition of cumene hydroperoxide to form phenol and acetone as principal products, followed by distillation to remove the acetone which has a lower boiling point than phenol. We have now found that 2- and 3-methylbenzofuran (collectively or individually MBF) can be effectively and economically removed from phenol by treatment with an aromatic sulfonic acid resin or a solid superacid catalyst compound at moderate temperatures provided that acetol (hydroxyacetone), another phenol impurity, is absent or present in the phenol at low levels, for example in an amount not to exceed 260 ppm, preferably not to exceed 200 ppm, more preferably not to exceed 100 ppm, most preferably not to exceed 5 ppm. At higher concentrations of acetol, the effect of resin treatment decreases and becomes progressively less economically attractive.
Strong acid resins useful for this invention contain aromatic sulfonic acid groups and typically consist of granules of sulfonated crosslinked polystyrene. Such aromatic sulfonic acid resins are available commercially, for example Amberlyst® 15 resin, a bead form sulfonic acid cation exchange resin available from Rohm and Haas. Additionally, solid superacid catalyst systems may be used. These systems have been developed as alternatives to liquid acid systems such as hydrofluoric acid used for petroleum acylation operations. Some are obtained from existing systems (AICI3, SbF5, SO42- on a supporting substrate of Zr02 or Ti02) by attaching existing strong acid constituents to oxide or salt substrates to immobilize the acid activity. Others are more novel heteropolyacids made from metal oxide clusters (tungsten and molybdenum). Representative catalysts are
discussed in "Solid Superacid Catalysts," Makoto Misuno and Toshio Okuhara, Chemtech. November 1993. Solid-superacid catalyst compounds are defined herein as those acid compounds wifli acid strength greater than that of 100% H2SO4.
The effectiveness of the treatment with resin increases with increasing temperature within the range of stability of the resin itself, for example within the range of 70 to 120° C, more preferably 80 to 110° C. Higher contact times are also more effective but increase the cost of the treatment. The contact of the phenol with the acid resin can be accomplished in known ways, such as by stirring the resin beads with the phenol, or by passing the phenol through a bed of acid resin, which may be the preferred commercial alternative. The effectiveness of temperature and contact time are demonstrated in the following examples. See example 1 for a definition of the unit of bed volume/hour, which for this invention is preferred to be 1 to 10, more preferably 2 to 6 bed volume/hour. In these examples analysis of 2-MBF was by conventional gas chromatography when present in concentrations of 1 ppm or greater. Below that concentration, liquid chromatography was performed using a non-polar, octadecylsilane column and a UV detector set at a wave length of 254 nm. Methanol/water was used as the eluent at ambient temperature at the constant composition of 90/10 by volume. Calculations of 2-MBF concentrations were based on comparisons of peak areas to calibration standards.
Example 1
Phenol containing less than 1 ppm acetol and amounts of MBF as indicated in Table 1 under "inlet" was passed through a bed of acid resin (Amberlyst 15) at the rates and temperature indicated. Bed volume is a volume of phenol corresponding to the volume of the resin bed used. The unit bed volume/hour is inversely proportional to contact time. The results of analyses on outlet samples show that the treatment is more effective at higher temperature and lower bed volume/hr values (higher contact times). The results also show that MBF levels can be reduced to less than 0.1 ppm.
Example 2
Phenol containing amounts of acetol and MBF as indicated under "inlet" in Table II was passed through a bed of acid resin (Amberlyst 15) at 4.0 bed volumes/hr. Samples were taken after the resin bed and analyzed. The results show that
although acetol was removed by the treatment, to levels of less than 1 ppm, MBF could not be lowered to less than 4 ppm.
Example 3
Phenol containing 20 ppm MBF and amounts of acetol of less than 1,200, and 500 ppm, respectively was passed through a bed of acid resin (Amberlyst 15) at 4 bed volumes/hour at different temperatures as shown on Table III. Samples were taken after the resin bed and analyzed. The results show that acetol hampers removal of MBF by the treatment and does so to a greater extent at higher temperatures. At 500 ppm acetol level and 110°C there was no removal of MBF
TABLE 1 Effect of temperature and contact time on removal of MBF from phenol containing less than 1 ppm acetol.
2 Bed Volumes/hr. 4 Bed Volumes/hr. 6 Bed Volumes/hr.
T (°C) Inlet/Outlet Inlet/Outlet Inlet/Outlet
65 20ppm/ 80 16/ 95 17/ 110 17/ TABLE II Effect of acetol concentration on removal of MBF from phenol by acid resin at 4 bed volumes/hr.
MBF Acetol
T (°C) Bed Inlet/Outlet Inlet/Outlet
80 20/4 ppm 250/ 95 18/5 260/ 95 18/5 250/ 110 22/8 250/ 116 25/11 260/ 95 20/10 500/ 110 25/25 500/
TABLE III Effect of temperature and acetol level on MBF removal from phenol by acid resin at 4 bed volumes/hr.
Acetol at Bed Inlet MBF at Outlet
Temperature 80°C 90°C 110°C
200 45 8
500 Not run 10 25

We Claims:
1. A process for the production of phenol having a reduced level of methylbenzofuran, the
process comprising the steps of:
treating the phenol of the kind such as herein described in a conventional manner to reduce the level of acetol to an amount not exceeding 260 ppm;
contacting the phenol so produced with an aromatic sulfonic acid resin or a solid super acid catalyst compound at a temperature in the range of from 70°C to 120°C at a rate of from 1 to 10 bed volumes per hour to reduce the level of methylbenzofuran by conversion to higher boiling compounds; then
distilling the phenol so produced to separate the phenol from the higher boiling compounds.
2.. The process as claimed in claim 1, wherein the step of treating the phenol to reduce the
level of acetol comprises treating the phenol with an amine.
3- The process as claimed in claim 1, wherein the step of treating the phenol to reduce the
level of acetol comprises treating the phenol with an amine to reduce the level of acetol to an amount not to exceed 5 ppm, and the phenol so produced is contacted with an aromatic sulfonic acid resin in a resin bed at a temperature in the range of from 90° C to 110° C at a rate of from 2 to 6 bed volumes per hour.
4. A process for the production of phenol having a reduced level of methylbenzofuran substantially as hereinbefore described with reference to the foregoing examples.

Documents:

792-del-1995-abstract.pdf

792-DEL-1995-Assignment-(12-12-2011).pdf

792-del-1995-assignment.pdf

792-del-1995-claims.pdf

792-DEL-1995-Correspondence Others-(12-12-2011).pdf

792-del-1995-correspondence-others.pdf

792-del-1995-correspondence-po.pdf

792-del-1995-description (complete).pdf

792-del-1995-form-1.pdf

792-del-1995-form-10.pdf

792-del-1995-form-13.pdf

792-DEL-1995-Form-16-(12-12-2011).pdf

792-del-1995-form-2.pdf

792-del-1995-form-3.pdf

792-del-1995-form-4.pdf

792-del-1995-form-6.pdf

792-del-1995-form-9.pdf

792-DEL-1995-GPA-(12-12-2011).pdf

792-del-1995-gpa.pdf

792-del-1995-Petition Others-(23-04-2012).pdf

792-del-1995-petition-others.pdf

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Patent Number

191201

Indian Patent Application Number

792/DEL/1995

PG Journal Number

40/2003

Publication Date

04-Oct-2003

Grant Date

06-May-2004

Date of Filing

28-Apr-1995

Name of Patentee

SUNOCO, INC.

Applicant Address

1801 MARKET STREET, PHILADELPHIAL, PENNSYLVANIA 19103, UNITED STATE OF AMERICA.

Inventors:

#	Inventor's Name	Inventor's Address
1	THEODORE JOHN JENCZEWSKI	2431 VIBURG COURT, MIDLOTHIAM, VIRGINIA 23113, USA.
2	LAMBERTO CRESCENTINI,	4211 DANIEL STREET, CHESTER, VIRGINIA 23831, USA.
3	JAMES ALPHONSE KWEEDER	2835 PINE MEADOW CIRCLE, CHESTER, VIRGINIA 23831, USA.

PCT International Classification Number

C07C 39/04

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	08/254,729	1994-06-06	U.S.A.