DESCRIPTION
PHENOL PURIFICATION PROCESS
5 TECIENICAL FIELD
[ O O O l ]
The present invention r e l a t e s t o a phenol p u r i f i c a t i o n
process, and p a r t i c u l a r l y a process for purifying a phenol
r e s u l t a n t by cumene method.
10
m C K G R O m ART
[0002]
Phenolisproducedthrougha step of oxidizingalkylbenzene
t o alkylarylhydroperoxide, a step of concentrating an oxidation
15 reaction product of alkylbenzene, a step of subjecting the
concentrated solution t o cleavage i n t o phenol and a ketone with
a n a c i d c a t a l y s t , astepofneutralizingtheacidcleavageproduct,
andastepofseparatingtheacidcleavageproductbydistillation.
[0003]
20 As a process for producing phenol, for example, a process
for acid decomposition of cumene hydroperoxide obtained by
oxidationofcumeneiswellknown. Theaciddecompositionproduct
in t h i s process contains, i n addition t o phenol and acetone as
main components, various by-products such as a-methylstyrene,
acetophenone, cumylphenol, 2-phenyl-2-propanol (also called
a-dimethylphenyl carbinol) and unreacted cumene, and various
carbonyl compounds such as a trace amount of hydroxyacetone (HA)
and a-phenylpropionaldehyde (a-PPA). In the application of
5 phenol, an example of which is polycarbonate manufactured from
diphenylolpropane (also called bisphenol A) as a raw material,
high-purity phenol is required.
[0004]
For such a high purity phenol, it is necessary that the
10 content of hydroxyacetone (HA) as an impurity is reduced to 30
ppm or less, preferably 10 ppm or less. In addition, it is
necessary that the total amount of other aliphatic and aromatic
carbonyl compounds contained, i.e., total amount of carbonyl
compounds other than HA, is reducedto100 ppmor less, preferably
15 50 ppm or less. In order to obtain such a high-purity phenol,
purification is carried out, wherein most of the low-boiling
substances such as acetone, cumene, water and a-methylstyrene,
andmost of the high-boiling substances such as acetophenone and
2-phenyl-2-propanolare removed froma neutralization product of
20 the acid decomposition product by means of fractional
distillation to give a phenol fraction, and further the aliphatic
carbonyl compounds such as hydroxyacetone, and the aromatic
carbonyl compounds such as a-phenylpropionaldehyde are removed
fromthe phenol fraction. However, it is particularly difficult
to remove those carbonyl compounds from phenol, which thus
deteriorates the quality of phenol as a product.
[0005]
Fora conventional process forproducinghigh-purityphenol,
5 for example, JP-B No. 37-11664 (Patent Document 1) proposes a
process inwhich hydroxyacetone andphenol are subjectedto react
bybringing crude phenol (contentofhydroxyacetone: 200ppm) into
contact with an activated aluminacatalyst at 360°C to give
2-methylbenzofuran (2-MBF), and phenol and 2-methylbenzofuran
10 are then separated by means of steam distillation. In addition,
JP-B No. 54-1289 (Patent Document 2) discloses a process in which
activated alumina is used for the purification of cresol. In
addition, JP-BNo. 42-12250 (PatentDocument3) proposes aprocess
which comprises bringing crude phenol into contact with a
15 silica/alumina catalyst at 150 to 250°C to convert carbonyl
compound as an impurity to another compound, and separating the
compound and phenol by distillation. Moreover, GB Patent No.
1231991 (Patent Document 4) proposes a process which comprises
bringing crude phenol containing no water into contact with an
20 acidic ion exchange resin catalyst at 80 to 150°C to convert
carbonyl compound as an impurity to another compound, and then
separating the compound and phenol by distillation.
[0006]
However, the above methods cause a problem such that the
25 efficiency of the removal of impurities is insufficient, or that
phenol and a-methylstyrene, which are useful components in the
crude phenol, react with impurities, or each of them undergoes
addition reaction with the other or independently to produce
cumylphenol or olefin dimers, and thus the useful components are
lost.
CITATION LIST
PATENT DOCmNT
[0007]
[Patent Document 11 JP-B No. 37-11664
[Patent Document 21 JP-B No. 54-1289
[Patent Document 31 JP-B No. 42-12250
[Patent Document 41 GB Patent No. 1231991
S Y OF THE INVENTION
TECrnIW PROBLEM
It is an object ofthe present invention to provide aphenol
purification process capable of producing high-purity phenol,
comprising selectively hydrogenating target carbonyl compounds
to convert the carbonyl compounds to the corresponding alcohol
compounds without causing the loss of the useful componen-ts
mentioned above, and separating the alcohol compounds and phenol
by distillation.
T E C m P C m SOLUTION
The present inventors have made their earnest studies to
overcome the above problem and have found that by using a
copper-based catalyst to selectively hydrogenate carbonyl
compounds contained as impurities in phenol to convert the
5 carbonyl compounds to the corresponding alcohol compounds, the
above problem can be overcome, thereby completing the present
invention.
[OOlO]
That is, the present invention is summarized as a phenol
10 purificationprocess comprisingbringingphenolinto contact with
a copper-based catalyst in the presence of hydrogen to convert
aliphatic carbonyl compounds and aromatic carbonyl compounds
i contained in the phenol to corresponding alcohol compounds, and ~ separating the alcohol compounds and phenol by distillation.
I 15 Hereinafter, phenol containing impurities such as carbonyl
compounds is also referred to as "crude phenol", and phenol from
which impurities such as carbonyl compounds have been removed is
also referred to as "high-purity phenol".
[OOll]
20 The copper-based catalyst comprises at least one of copper
and copper oxide (A) and oxide (s) of at least one element selected
from silicon, aluminum, zinc, chromium, bariumandmanganese (B).
[0012]
The weight ratio of at least one of copper and copper oxide
(A) to oxide(s) of at least one element selected from silicon,
aluminum, zinc, chromium, bariumandmanganese (B), both of which
constitute the copper-based catalyst, (A)/(B), is in the range
5 of from 9/1 to 1/9. The catalytic hydrogenation is performed
desirably at a reaction temperature of 50 to 300'C at a hydrogen
pressure of 0.5 to 30 MPa.
ADVANTAGEOUS EFFECTS OF THE INVENTION
10 [0013]
Accordingtothepresent invention, byusingacopper-based
catalyst such as a catalyst comprising at least one of copper and
copper oxide (A) and oxide(s) of at least one element selected
from silicori, aluminum, zinc, chromium, barium and manganese (B)
15 to hydrogenate carbonyl compounds contained in crude phenol to
convert the carbonyl compounds to the corresponding alcohol
compounds, it is possible to easily separate phenol by
distillation to produce high-purity phenol, while inhibiting the
loss of phenol and a-methylstyrene, which are useful components
20 in the crude phenol. Thus, the purification process of the
present invention is indus.trially of significant value.
BRIEF DESCRIPTION OF B19AWPNG
Fig. 1 is a figure showing the test result of distillation
ofhydroxyacetone (HA), ahydrogenatedproductofhydroxyacetone,
i.e., propylene glycol (PG), a hydrogenated product of
a-phenylpropionaldehyde (a-PPA), i.e., 2-phenyl-1-propanol
(PPnol), and phenol (See Reference Example 1).
DESCRIPTION OF EbaBODIMENTS
[0015]
The phenol to be purified in the present invention is a
residue obtained by removing light fractions (for example, most
part of acetone, cumene and a-methylstyrene) by fractional
distillation of a neutralizedproduct of acid-decomposedproduct
obtained by acid-decomposing cumene hydroperoxide obtained from
theoxidationreactionofcumene, anditscomposition is as follows.
This compositional range is set forth just in order to give an
example, and not to limit the technical scope of the present
invention.
Phenol 87.0 to 95.6 wt%
Cumene 1.0 to 0.1 wt%
a-methylstyrene 2.0 to 0.1 wt%
Hydroxyacetone 0.5 to 0.1 wt%
a-phenylpropionaldehyde 0.5 to 0.1 wt%
Acetophenone 4.0 to 2.0 wt%
2-phenyl-2-propanol 1.0 to 0.5 wt%
Other high-boiling components 4.0 to 1.5wt%
[0016]
In the above phenol fraction, separating cumene and
a-methylstyrene as light fractions, and acetophenone,
5 2-phenyl-2-propanol and other high-boiling components as heavy
fractions from phenol is relatively easy by distillation.
However, separatingcarbonylcompounds suchas hydroxyacetone and
a-phenylpropionaldehyde fromphenolbydistillation is difficult.
In the present invention, such carbonyl compounds are converted,
10 by hydrogenation reaction using a specific catalyst, to the
corresponding alcohols, and the corresponding alcohols are
removed by distillation. This characterizes the phenol
purification process of the present invention. A phenol
preferred in the purification process of the present invention
15 is phenol containing carbonylcompound as animpuritywhereinthe
carbonylcompound is at least one compound selected fromaromatic
carbonyl compounds and aliphatic carbonyl compounds, and more
specifically, phenol containing, as an impurity, hydroxyacetone
(HA) as an aliphatic carbonyl compound, and/or
20 a-phenylpropionaldehyde (a-PPA) as an aromatic carbonylcompound.
The particularly preferred phenol is phenol containing not more
thanlwt% of hydroxyacetone (HA). In the hydrogenation reaction
according to the present invention, HA is converted to propylene
glycol (PG), and a-PPA is converted to 2-phenyl-1-propanol
( PPnol) .
[0017]
The copper-based catalyst used as the catalytic
5 hydrogenation catalyst in the present invention is usually a
catalyst comprising at least one of copper and copper oxide (A),
preferablya catalystcomprisingat least one of copper andcopper
oxide (A) and oxide(s) of at least one element selected from
silicon, aluminum, zinc, chromium, bariumandmanganese (B). The
10 copper-based catalyst is more preferably a catalyst consisting
of at least one of copper and copper oxide (A) and oxide(s) of
at least one element selected from silicon, aluminum, zinc,
chromium, barium and manganese (B); and is particularly
preferably a catalyst consisting of at least one of copper and
15 copper oxide (A) and oxide(s) of at least one element selected
from silicon, zinc, chromium, barium and manganese.
The method for preparing the copper-based catalyst is not
particularly limited, and an exemplary method thereof is as
20 follows. That is, the catalyst used in the present invention can
be prepared by using, as raw materials, at least one kind selected
from a nitrate, a sulfate, a carbonate, an acetate, a chloride,
an oxide, a hydroxide and the like of copper, aluminum, zinc,
chromium, barium and manganese, and further at least one kind
selectedfroma silicate (for example, sodiumsilicate, potassium
silicate), an alkoxide compound of silicon (for example,
tetramethoxysilane, tetraethoxysilane), a halogen compound of
silicon (tetrachlorosilane, tetrabromosilane) and the like, by
5 known method such as co-precipitation method, immersion method
and kneading method.
[0019]
Here, in the catalyst used in the present invention, the
weight ratio of at least one of copper and copper oxide (A) to
10 oxide (s) of at least one element selected from silicon, aluminum,
zinc, chromium, barium and manganese (B) , [ (A) / (B) 1, is not
particularly limited, but is desirably in the range of from 9/1
to 1/9, particularly desirably in the range of from 4/1 to 1/4.
[0020]
15 A catalyst included in the catalyst used in the present
invention, i.e., the catalyst comprising at least one of copper
and copper oxide (A) and oxide (s) of at least one element selected
from silicon, aluminum, zinc, chromium, barium and manganese (B)
may be a catalyst prepared by the known methods described above,
20 such as co-precipitation method, immersion method and kneading
method, or a commercially available catalyst (for example, E35S
manufactured by JGC Catalysts and Chemicals Ltd., and G-22 and
G-99 manufactured by Sud Chemie Catalyst).
[0021]
The shape of the catalyst used in the present invention
is not particularly limited, but the catalyst is desirably a
tablet-shaped or a noodle-shaped. These shapes are easily
available industrially. The size of the catalyst used in the
5 present invention is determined according to the inner diameter
of a reactor column employed, but the catalyst having a diameter
of 2 to 6 mm and a height of 2 to 6 mm is preferable.
[0022]
Examples of a reactor for performing the purification
10 process of the present invention are a batch-type reactor, a
fixed-bed continuous reactor, a fluidized-bed continuous reactor
and a moving-bed continuous reactor. The use of a fixed-bed
continuous reactor, which equipment is simple, is desirable.
15 In order to control rapid heat generation when
hydrogenation reaction 1s initiated and to allow the catalyst to
effectively exhibit its activity, it 1s effective that the
copper-based catalyst usedinthe present invention is subjected
to preliminary reduction treatment in accordancewith anordinary
20 method. In general, this reduction treatment is performed by
bringing the catalyst into contact with a hydrogen gas at 100 to
300°C.
100241
The hydrogenation reaction temperature is usually 50 to
300aC, preferably 80 to 200°C.
[0025]
The reaction pressure is generally a hydrogen pressure of
5 0.5 to 30 MPa, preferably 1 to 10 MPa. The reaction time, in the
case of batch reaction, is usually 1 to 20 hours. In the case
of continuous-type reaction, the feeding rate (LHSV) ofthe crude
phenol per unit volume of the solid catalyst in the reaction is
desirably 0.5 hr-I to 20 hr-l, more desirably 1 hrF1 to 10 hr-I.
10 [0026]
When a continuous reactor is usedinthe present invention,
the reactor employed may be composed of a single reactor, or a
plurality of reactors. Particularly, when the reactor is
composed of a plurality of reactors, reaction conditions can be
15 controlled with greater precision by serially arranging the
reactors.
[0027]
In the present invention, carrying outa knownpurification
method, such as a purification procedure using an acidic ion
20 exchange resin, after or before performing the reaction of
converting carbonyl compound to alcohol in the presence of
hydrogen, does not limit the present invention in any way, and
is determined as needed by person conducting purification
procedure.
I
!
I E LES
[0028]
Hereinafter, with reference to Examples, the present
5 invention is described more specifically, but the present
invention is in no way limited by these Examples. The conversion
percentage of carbonyl compounds and the selectivity of
corresponding alcohol compounds were calculated from values
obtained in analysis by gas chromatography. The concentration
10 unit ppm is all based on weight.
[0029]
[Example 11
5 g of E35S catalyst (CuO/Si02 = 67/27 in weight ratio)
manufactured by JGC Catalysts and Chemicals Ltd., and 250 g of
15 phenol containing 1800 ppm of hydroxyacetone (HA), 1300 ppm of
a-phenylpropionaldehyde (a-PPA), 500 ppm of a-methylstyrene
(a-MS), 6000 ppm of 2-phenyl-2-propanol (Cnol), 2.41 wt% of
acetophenone (Anone) and other impurities were weighed, and
introduced to a SUS 316 500-ml autoclave equipped with an
20 electromagnetic induction rotating stirring device. The inside
of the autoclave was purged with nitrogen (three times each at
0.9 MPa) , and was purged with hydrogen (three times each at 0.9
MPa). The autoclave was filled finally with hydrogen at room
temperature until the internal pressure reached 0.8 MPa, and was
sealed. The autoclave was heated to 160°C with stirring at a
stirring rate of 450 rpm. Thereby, catalytic hydrogenation
reactionwasperformed. Twelve hour sthereafter, theheatingwas
stopped. The autoclave was sufficiently cooled, and the inside
5 of the autoclave was purged with nitrogen, and then the autoclave
was opened. The content was filtered to remove the catalyst.
Analysis of the resultant reaction liquid by gas chromatography
found that HA conversion was 89.2%, a-PPA conversion was 99.3%
and Anone conversion was 25.7%, and the corresponding alcohol
10 compounds were obtained. Within the scope of analysis precision
of gas chromatography, difference was notobservedbetweenbefore
and after the reaction in terms of the concentration of dimers
of a-methylstyrene (MSD), the concentration of the reaction
product between phenol and a-MS, i. e., cumylphenol (CP) , and the
15 concentration of phenol. Results are shown in Table 1.
[0030]
[Examples 2 and 31
The reaction was performed in the same manner as Example
1, except that the catalyst used in Example 2 was G-22 catalyst
20 (CuO/Cr2O3/BaCrO4/Si0=2 50/35/10/5 in weight ratio) manufactured
by Sud Chemie Catalyst, and the catalyst used in Example 3 was
G-99 catalyst (CuO/Cr203/BaCr04/Mn0 = 45/45/5/5 in weight ratio)
manufactured by Sud Chemie Catalyst. Results are shown in Table
1.
[0031]
[Catalyst Preparation Example 11
(Preparation of Catalyst composed of zinc oxide and at least one
of copper and copper oxide)
5 Asolutionpreparedbydissolving 45.55 gof copper nitrate
trihydrate and 54.90 g of zinc nitrate hexahydrate in 375 ml of
distilled water was added to a solution prepared by dissolving
41.50 g of sodium carbonate in 375 ml of distilled water at room
temperature with stirring, and the mixture solution was allowed
10 to react for 2 hours. After the reaction, aprecipitatedreaction
I product was filtered and washed with distilled water. The
i
I resultant solid after the filtering and washing was collected,
i I
and dried at llO'C for 5 hours, and then calcined in air at 400°C
for 5 hours. The obtained solid was a catalyst substantially
15 composed of copper oxide and zinc oxide at a weight ratio of 1/1.
The obtained catalyst was molded into a tablet-shape with 29R
manufactured by Kikusui Seisakusho Ltd., to prepare a catalyst.
This catalyst was used in a reaction.
[0032]
20 [Example 41
A fixed-bed reaction tube was filled with 100 ml of the
molded catalyst obtained in Catalyst Preparation Example 1, and
was chargedwithphenolcontain~ngl800ppmofhydroxyacetone( HA),
1300 ppm of a-phenylpropionaldehyde (a-??A), 6000 ppm of
2-phenyl-2-propanol (Cnol), 2.41wt% of acetophenone (Anone) and
other impurities, and hydrogen under upflow conditions. Then,
hydrogenation reaction was performedinthe fixed-bed continuous
reactor at a temperature of 16OSC, at a pressure of 1.6 MPa, at
5 a liquid hourly space velocity (LHSV) of 2 hr-l, at a molar ratio
of hydrogen/carbonyl compound of 20. The specimen for analysis
was collected every hour, andwas analyzedby gas chromatography.
Results are shown in Table 1
10 [Example 51
The reaction was performed in the same manner as Example
4, except that the fixed-bed reaction tube was filled with 100
mlofE35S catalyst (CuO/SiO2= 67/27 inweight ratio) manufactured
by JGC Catalysts andchemicals Ltd., andthe reaction temperature
15 was 140'C. The specimen for analysis was collected every hour,
and was analyzed by gas chromatography. liesuits are shown in
Table 1.
[Table 11
5 * Concentration of MSD, CP and PI-I: concentrations indicated in
the upper side arc values before hydrogenation, and
concentrations indicated in the lower side are values after
hydrogenation.
[Comparative Example 11
5 g of a cation exchange resin (Amberlyst-15E), and 250
g of phenol containing 1800 ppm of hydroxyacetone (HA), 1300 ppm
of a-phenylpropionaldehyde (a-PPA), 500 ppm of a-methylstyrene
15 (a-MS), 6000 ppm of 2-phenyl-2-propanol (Cnol), 2.41 wt% of
acetophenone (Anoire) and other impurities were weighed, and
introduced to a SUS 316 500-ml autoclave equipped with an
electromagnetic induction rotating stirring device. The inside
of the autoclave was purged with nitrogen (three times each at
20 0.5 MPa), and then the autoclave was sealed. The autoclave was
heated to llO'C with stirring at a stirring rate of 450 rpm.
Thereby, the reaction was performed. Two hours thereafter, the
heating was stopped, and the autoclave was sufficiently cooled
andthenopened. The content was filteredto remove the catalyst.
Analysis of the resultant reaction liquid by gas chromatography
found that HA conversion was loo%, a-PPA conversion was 100% and
Anone conversion was 1%, but a-MS contained in the raw material
5 and a-MS generated by dehydration reaction of Cnol, which are a
useful component, reacted in their whole amount with phenol, to
I
be converted to cumylphenol.
[Comparative Example 21
10 The reactionwas performedinthe samemanner ascomparative
Example 1, except that in the Comparative Example 1, the ca.tion
exchange resin was replaced with a hydrogen exchange
mordenite-type zeolite having an acidity function of Ho < -8.2
andthe reaction temperature was 160'C. As a result, it was found
15 that HA conversion was 95%, a-PPA conversion was 92% and Anone
conversionwas 0%, buta-MS containedinthe rawmaterialanda-MS
generated by dehydration reaction of Cnol, which are a useful
component, reacted in their whole amount with phenol, to be
converted to cumylphenol.
20 [0037]
[Example 61
7.5 g of a ShiftMax 210 catalyst (CuO/ZnO = 42/47 in weight
ratlo) manufactured by Sud Chemie Catalyst, and 125 g of cumene
wereweighed, andintroducedto a glass 300-ml flask equippedwith
a s t i r r i n g device and a condenser. The f l a s k was purged with
nitrogen by feeding 500 ml/min of nitrogen gas thereto for 10
minutes. Thereafter, with s t i r r i n g , the f l a s k was heated i n an
o i l b a t h t o 1 4 0 e C , and100ml/minofhydrogengaswasblownthereto
5 a t atmospheric pressure. Thereby, c a t a l y s t reduction treatment
wasperformedfor5hours. Thereafter, the flaskwas s u f f i c i e n t l y
cooled t o c o l l e c t cumene. Then, a 125 g of phenol containing 1 . 0
wt%ofhydroxyacetone (HA) wasweighed, a n d i n t r o d u c e d t o t h e f l a s k
having t h e c a t a l y s t . With s t i r r i n g , t h e f l a s k was heated in an
10 o i l bath t o 80°C, and 100 ml/min of hydrogen gas was blown thereto
a t atmospheric pressure. Thereby, c a t a l y t i c hydrogenation
reaction was performed. Five hours t h e r e a f t e r , t h e heating was
stopped. The flaskwas s u f f i c i e n t l y c o o l e d t o c o l l e c t a reaction
l i q u i d . Analysis of the reaction l i q u i d by gas chromatography
15 found t h a t HA conversion was 14.3%, and cyclohexanol, which was
a nuclear hydrogenation product of phenol, was given a t not more
than 10 ppm.
[Comparative Example 31
20 7.5 g of a 2% palladium carbon beads c a t a l y s t manufactured
by N.E. CHEMCAT CORPOWTION, and 125 g of phenol containing 1 . 0
w t % ofhydroxyacetone (HA) wereweighed, andintroducedto a glass
300-ml f l a s k equipped with a s t i r r i n g device and a condenser.
With s t i r r i n g , t h e f l a s k was heated i n an o i l bath t o 80'C, and
100 ml/min of hydrogen gas was blown thereto at atmospheric
pressure. Thereby, catalytic hydrogenation reaction was
performed. Five hours thereafter, the heating was stopped. The
flask was sufficiently cooled to collect a reaction liquid.
5 Analysis of the reaction liquid by gas chromatography found that
HA conversion was 0.0%, which showed that no hydrogenation
reaction of hydroxyacetone proceeded, and that cyclohexanol,
which was a nuclear hydrogenation product of phenol, was given
at 3000 ppm, which confirmed the loss of phenol, a useful
10 component.
[0039]
[Comparative Example 41
The reactionwasperformedinthe samemannerascomparative
Example 3, exceptthat2.5 gof R-200L catalyst (bulkRaneynicke1)
15 manufactured by NIKKO RICA CORPORATION. Analysis by gas
chromatography found that HA conversion was 10.0%, and that
cyclohexanol, whichwas anuclearhydrogenationproductofphenol,
was given at 1000 ppm, which confirmed the loss of phenol, a useful
component
[Reference Example 11
The separability in distillation of hydroxyacetone (HA),
a hydrogenatedproduct of hydroxyacetone, i.e., propylene glycol
(PG), and a hydrogenated product of a-phenylpropionaldehyde
(a-PPA), i.e., 2-phenyl-1-propanol (PPnol), and phenol was
studied in the following manner. A raw material prepared by
adding HA, PG and PPnol each in an amount of 1000 ppm to phenol
was subjectedto fractional distillation using an Oldershawglass
distillation column with 30 trays. The distillation was
performed at a raw material-feeding amount of 800 g, at a reflux
ratio of 2, at a pressure of 200 Torr. The distillates were
analyzed by gas chromatography, and analysis found that HA was
detected in all the distillates, but PG and PPnol were detected
in none of the distillates. Results are shown in Fig. 1.
'I
:I
,i 1. A phenol purification process comprising bringing
5 phenol into contact with a copper-based catalyst in the presence
of hydrogen to convert carbonyl compound containedinthe phenol
to corresponding alcohol compound, and separating the alcohol
compound and phenol by distillation.
10 2. The phenol purification process according to Claim
1, whereln the carbonyl compound contained in the phenol is at
least one compound selected from aromatic carbonyl compounds and
aliphatic carbonyl compounds.
15 3. The phenol purification process according to Claim
1 or 2, wherein the copper-based catalyst comprises at least one
of copper andcopper oxide (A) andoxide(s) of at least one element
selected from silicon, aluminum, zinc, chromium, barium and
manganese (B) .
4. The phenol purification process according to Claim
3, wherein the weight ratlo (A)/(B) In the copper-based catalyst
is in the range of from 9/1 to 1/9.
5. The phenol purification process according to any one
of Claims 1 to 4, whereinthe catalytichydrogenation is performed
a t a reaction temperature of 50 to 300'C at a hydrogen pressure
of 0.5 t o 30 MPa.