High selective method of phenol and acetone production

Disclosed is a process for the cleavage of technical cumene hydroperoxide (CHP) into phenol, acetone and .alpha.-methylstyrene. In a first stage, the CHP cleavage process is conducted in such a way to maintain the heat generation rate and the heat removal rate balanced in each of the CHP cleavage reactors. The cleavage of the CHP is conducted under substantially isothermal conditions at a temperature in the range of 47-50.degree. C. In the second stage of the process dicumylperoxide (DCP) and dimethylbenzene alcohol (DMBA) cleavage is carried out in a multi-section plug-flow reactor under non-isothermal conditions at a controlled temperature increase. The temperature is controlled with the use of thermocouples installed in each section of the reactor. The obtained temperature profile is compared with the temperature profile required by the kinetic model based on .DELTA.T in each section of the reactor. Based on any obtained fluctuations at least one of the amount of water additionally fed to the reactor, the temperature and the degree of sulfuric acid conversion into NH.sub.4 HSO.sub.4 are adjusted.

BACKGROUND OF THE INVENTION 
This invention relates to the field of petrochemical synthesis, and in 
particular, to a method of production of phenol, acetone and 
alpha-methystryrene (AMS) by the cumene method. 
There are a number of methods known to produce phenol and acetone by using 
acidic cleavage of technical cumene hydroperoxide (CHP). The main 
difference between the known methods is in using different reaction 
mediums and alternate techniques for removing the heat (380 Kkal/kg) 
generated during the process of CHP cleavage. 
In these prior art processes the best selectivity is obtained by using an 
equimolar mixture of phenol and acetone as a reaction medium. On a 
relative basis, 15-30% of acetone, based on technical CHP, is added to 
this mixture. This is illustrated in Russian Application No. 
9400736/04/007229 dated Mar. 1, 1994 and U.S. Pat. No. 4,358,618. This 
allows one to obtain a good process selectivity as determined by the yield 
of the desired by-product, AMS, formed from dimethylbenzene alcohol (DMBA) 
present in technical cumene hydroperoxide. The obtained AMS yield in is 
about 80%. 
During the CHP cleavage, the heat generated is removed. In the process 
according to U.S. Pat. No. 2,663,735 the heat is removed by acetone 
evaporation and acetone recycle to the reactor. The generated heat can 
also be removed by the use of a cooling medium such as cooling water. 
During the adiabatic cleavage of 100% CHP the temperature is increased to 
about 700.degree. C. under the influence of an acidic catalyst. The heat 
is generated spontaneously. Because of the rapid heat release, the CHP 
cleavage process is considered very dangerous. Consequently, the 
combination of heat generation and heat removal is of high priority for 
improving process safety. 
In the process of U.S. Pat. No. 2,663,735, the reaction heat is removed by 
acetone evaporation and the heat generation and the heat removal are fully 
combined. The heat generated in the process of cleaving 1 ton of CHP 
requires feeding approximately 2.2-3 tons of acetone to the reactor. The 
evaporated acetone is to exhausted from the reactor, condensed and 
continuously recycled to the reactor. As a result, the reactor is operated 
in a heat stable manner as is required for process safety. 
However, the heat stable condition is obtained only by the use of a 
comparatively high sulfuric acid concentration of 1200-1300 ppm. However, 
the high H.sub.2 SO.sub.4 concentration, which is needed due to the large 
amount of acetone fed into cleavage products, decreases the activity of 
sulfuric acid which is the CHP cleavage catalyst. Thus, high acid 
concentration results in a low yield of desired products and a high 
content of microimpurities (about 1500 ppm) such as mesithyl oxide, 
hydroxyacetone, and 2-methylbenzofurane which substantially adulterate the 
phenol quality. While the process chemistry requires a low sulfuric acid 
concentration of about 100-300 ppm, this can not be achieved in practice 
since CHP accumulates in the reactor bottoms because of the sharp decrease 
of the CHP cleavage rate that results in a large heat release. i.e. when 
decreasing the sulfuric acid concentration the reactor is operated under 
unstable heat conditions. Actually the process achieves thermal stability 
only at a high sulfuric acid concentration but this results in a low 
process selectivity. Therefore, in the process employing acetone 
evaporation, the objectives of heat stability and obtaining a high process 
selectivity are in irreconcilable conflict. 
In the processes of the above referenced Russian application, U.S. Pat. 
Nos. 4,358,618 and 5,254,751, reaction heat is removed with the reaction 
products or reaction cleavage mass (RCM) by multiple circulations through 
water cooled heat exchangers. The heat exchangers, which may number from 2 
to 6, are in fact the reactors wherein the CHP cleavage occurs. The heat 
stability of the process (i.e. the process safety) depends on the 
composition of the reaction products, the range of the acid concentration, 
the temperature profile and, hence, CHP conversion distribution in the 
reactors. The process stability deteriorates at higher CHP conversion in 
the first reactor and as the temperature difference between the first and 
the subsequent reactors increases. In practice, the more the conditions of 
the process are non-isothermal, the more precarious is the process state. 
In the process according to the Russian application, the CHP and DCP 
cleavages are performed in two stages. CHP cleavage reactors (mixing 
reactors) and the DCP conversion reactor (plug-flow reactor) are operated 
at the same pressure. 
The CHP and DCP cleavage are performed in an equimolar mixture of phenol 
and acetone containing up to 12 wt % of cumene. To reduce the acidic 
properties of the sulfuric acid and, therefore, to increase the yield of 
such desired products as phenol, acetone and AMS, additional acetone is 
added into the reaction products according to the following algorithm: 
EQU G.sub.ac. =G.sub.CHP .times.0.125 [CHP]+35/(G.sub.CHP .times.[CHP]), 
where: 
G.sub.ac., G.sub.CHP represent the flow rate of additional acetone and 
technical CHP, respectively, in kg/hr and 
[CHP] is CHP concentration of technical grade CHP (wt %) 
that is equal to 12-14% rel. of acetone based on technical CHP feed rate. 
CHP conversion, depending on the feed rate, is maintained in the first 
reactor at 62-75%, in the second reactor at 87-94% and in the third 
reactor at 94-98%. The corresponding temperatures in these reactors are 
67-79.degree. C., 78-67.degree. C. and 69-60.degree. C., respectively. The 
above algorithm for the feeding of additional acetone, the temperature, 
and CHP conversion distribution in the reactors allow the process to 
operate within a wide range of feed rates. 
The CHP concentration at the outlet of the reactors of the first stage is 
0.14-0.43 wt.-% that corresponds to a .DELTA.T of 1-3.degree. C. in the 
calorimeter which controls the first stage of the process 
Water is fed to the DCP cleavage reactor in an amount so as to provide a 
water concentration in the reaction products of 1.3-2.0 wt.-%. The 
operation of the reactor of the second stage is controlled by .DELTA.T 
equal to 1-3.degree. C. of the calorimeter installed in the line before 
the DCP cleavage reactor. In the DCP cleavage reactor the process 
conditions are isothermal. Different temperatures from 94.degree. C. at 
the low feed rates to 99.degree. C. at high feed rates are maintained in 
the DCP cleavage reactor. The entire process (1st and 2nd stages) is 
controlled by the temperature differential between the two calorimeters. 
This calorimeter temperature differential .DELTA. is 0.2-0.3.degree. C. 
In order to reduce non-selective losses in the acetone flash stage, ammonia 
is added into the line before the evaporator to convert sulfuric acid into 
the neutral salt (NH.sub.4).sub.2 SO.sub.4. As a result, AMS yields of 
78.8-79.6% of theory are obtained in the process. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a process to obtain a 
higher yield of desired products by increasing the AMS yield to 85-87% and 
reducing chemical losses in the cleavage product rectification columns. 
Another object is to increase the process safety by cleaving CHP under 
conditions which are substantially isothermal. 
Further objects of the invention are to reduce the energy consumption in 
the process by decreasing the amount of recirculating acetone and 
recuperating the heat with the DCP and DMBA cleavage reactor and to obtain 
stable DCP conversion in the second stage of the process at variable feed 
rates and fluctuating operating conditions. 
It is a further object of the process of the invention to decrease 
non-selective losses at the cleavage product rectification stage. These 
objects, and others, are obtained by the process of the invention. 
In the process of the invention, technical grade CHP containing DMBA is 
cleaved to phenol, acetone and .alpha.-methylstyrene. Technical grade CHP 
is introduced into at least the first of a series of at least three 
sequential reactors wherein the CHP is cleaved under the influence of an 
acidic catalyst. The reactors are maintained under substantially 
isothermal conditions in a temperature range of about 47 to 50.degree. C. 
to produce a product stream containing DCP and DMBA. The product stream is 
introduced into a cleavage reactor wherein the DCP is decomposed in a 
non-isothermal operation to a mixture containing at least one of phenol, 
acetone and .alpha.-methylstyrene. 
The advantages of the invention are obtained by selection and control of 
the temperature conditions at the first and second cleavages, the CHP 
conversion in the reactors of the first stage, the composition of the 
reaction products, and by changing the algorithm of the reactor control at 
the second stage of the process. 
The process of the invention, similarly to previously known phenol 
processes, comprises several main stages determining the selectivity of 
the process in total: 
1. Cumene (isopropylbenzene) oxidation with air and/or oxygen to cumene 
hydroperoxide (CHP); 
2. Acidic (H.sub.2 SO.sub.4) cleavage of the produced CHP; and 
3. Rectification of CHP cleavage products by the method of multi-step 
rectification 
The process of the invention shows an improvement of process consumption to 
parameters such as feed consumption value. More specifically, it has an 
improved CHP cleavage safety by balancing heat generation and heat removal 
rates and a decrease in steam consumption. The process embodies a new 
principle of the control over the second stage-dicumylperoxide (DCP) and 
dimethylbenzene alcohol (DMBA) conversion. It shows a decrease in chemical 
losses of desired products at the rectification stage obtained by changing 
the composition of the products at the DCP reactor outlet. 
The various features of novelty which characterize the invention are 
pointed out with particularity in the claims appended to and forming a 
part of this specification. For a better understanding of the invention, 
its operating advantages and specific objects obtained by its use, 
reference should be had to the accompanying drawings and descriptive 
matter in which there is illustrated and described a preferred embodiment 
of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The CHP and DCP cleavage process of the invention may be viewed as having a 
first and second stage for the purposes of description. In the first 
stage, CHP is cleaved and DCP is synthesized in mixing reactors. This 
cleavage is conducted under the influence of an acidic catalyst which is 
preferably sulfuric acid. 
Referring to FIG. 1, a feed stream 10 of technical CHP or containing cumene 
oxidized to CHP in accordance with known prior art processes and 
containing DMBA is introduced into the first of a cascade of reactors 12. 
In a preferred embodiment, cascade 12 includes 3 reactors 14, 16 and 18 
arranged in series. The reactors 14, 16 and 18 are mixing reactors with 
respect to byproduct reactions, and plug-flow reactors with respect to CHP 
decomposition reactions. For this purpose, a series of baffles (not shown) 
are installed in a shell part of each of the reactors 14, 16 and 18 to 
enable conversion of the reactors 14, 16, and 18 from mixing regime to 
plug-flow regime in each section of each reactor. Preferably, 6 to 16 
baffles are installed in each reactor. 
In the reactors 14, 16 and 18, the CHP is cleaved to form a first product 
stream 20 containing about 1% CHP, phenol and acetone, about 4-5% DCP to 
2-2.5% DMBA, approximately 1-1.5% AMS, and minimal amounts of 
byproducts--AMS dimers and complex phenols. The cleavage is brought about 
by the sulfuric acid which is at a concentration in the reaction products 
of not lower than 180 ppm and not higher than 200 ppm. The first product 
stream 20 exiting from reactor 18 is divided and a portion of that stream 
is recycled through line 22 to a pump 24 from which material is forwarded 
to reactor 14 after being combined with technical grade CHP feed stream 
10. The relative quantity of the recycled fraction of stream 20 to stream 
10 is about (8-40):1. Sulfuric acid 26 can be introduced in recycle line 
22. 
Additional acetone is fed to the first stage of the process. The amount of 
additional acetone is based on the technical CHP flow rate and is 
maintained within the range of 5-8% relative to the CHP flow rate to reach 
the required value of CHP conversion at varying feed rates and fluctuating 
operating conditions. The amount of additional acetone fed should not 
exceed 8%. 
The CHP conversion in reactors 14, 16 and 18 in series is maintained at 
42-50%, 67-73% and 78-82%, correspondingly. The temperature in each of the 
reactors 14, 16 and 18 is maintained between 47 and 50.degree.. Cooling 
water removes heat generated in the process. Preferably the temperature in 
reactor 14 is 47-50.degree. C., in reactor 16 is 50-48.degree. C., and in 
reactor 18 is 48-50.degree. C. That is to say that unlike the prior art, 
as illustrated by the above cited Russian application and U.S. Pat. No. 
5,254,751, the process conditions in the process of the invention are 
isothermal or at least substantially isothermal in reactors 14, 16 and 18. 
The above distribution of CHP conversion and temperature in the reactors 
enables one to balance the heat generation rate and heat removal rate by 
controlling the CHP cleavage rate. This balance results in a system 
wherein the heat is stabilized in all points of the reactors, thus 
promoting process safety. 
A substantially isothermal operation in reactors 14, 16 and 18 is obtained 
by operating with certain amounts of additionally fed acetone, certain 
water concentrations in the reaction products and obtaining a lower acid 
concentration in the reaction products. The combination of the above 
features results in a certain CHP cleavage rate, and, as a result, certain 
heat generation in each of the reactors 14, 16 and 18 in the first stage. 
Due to different cooling water flow rates to the first stage reactors, 
conditions at, or close to, isothermal are maintained. When .DELTA.T1--the 
difference between exit and entry temperatures of a flow calorimeter 
28--deviates from the required temperature by 8-9.degree. C., the 
temperature is corrected in the first reactor which maintains the required 
CHP conversion value, and, as a result, the temperature after the first 
reactor. The temperature after the last reactor of the first stage is also 
maintained by controlling the cooling water flow rate. Also cooling water 
is fed to the tube space of the second reactor but that flow rate is 
preferably kept stable at constant CHP feed rate. Such a method of 
operation provides conditions which are isothermal or substantially 
isothermal in the first stage CHP cleavage reactors. 
An advantageous aspect of the process of the invention is that it 
eliminates the increased temperature zones in the reactors that occurs in 
the conventional prior art cleavage methods. The rate of formation of 
undesired byproducts, such as AMS dimers and complex phenols, is decreased 
thus resulting in an increase of the CHP cleavage stage selectivity, and, 
as a result, the total process selectivity. 
The system for performing the process includes a temperature measuring 
arrangement which in FIG. 1 is illustrated as the calorimeter 28. 
The remaining non-recycled portion 30 of the product stream 22 is 
introduced into an intermediate vessel 32. Water 34 and a base 36, which 
is preferably NH.sub.4 OH, are mixed with the product stream 30 in vessel 
32. As indicated, a temperature measurement is made by a temperature 
measuring device 40 shown as a calorimeter in the tank discharge line 38. 
The mixed stream in line 38 is heated in preferably two stages by heat 
exchangers 42 (80-90.degree. C.) and 44 (90-100.degree. C.) so that the 
stream temperature increases by about 50-55.degree. C. 
The heated stream 46 is introduced into a reactor 48 for cleaving of DCP 
and DMBA dehydration. Reactor 48 is preferably a multi-stage or 
multi-section plug flow reactor with an internal baffle arrangement 
forming a plurality of sections or zones within the reactor 48. 
In plug flow reactor 48, the main reaction of DCP conversion into phenol, 
acetone and AMS and the side conversion reaction of DMBA into AMS desired 
byproduct occur. AMS is a desired product since it can be converted into 
cumene and then returned to the cumene oxidation stage. 
In reactor 48, the temperature of the feed is raised in a controlled manner 
to a temperature in the range of about 120 to 150.degree. C. and 
preferably to 140-146.degree. C. The change in reactor 48 is a 
self-sustaining reaction. Preferably, each section or zone of the reactor 
48 has independent temperature control by means of, for instance, a 
thermocouple and a temperature control feed back and forth system. 
A product stream 50 leaves reactor 48, passes through the heat exchanger 
42, where it transfers heat to stream 38 and enters evaporator 56 where 
the evaporation of the additionally fed acetone takes place. Stream 52 
leaves across heat exchanger 42 and is mixed with a base, such as NH.sub.4 
OH (54), and is then passed to an evaporator 56 wherein part of the 
acetone is evaporated along with parts of water, cumene and phenol. The 
evaporated phase 58 is condensed in condenser 60, separated and the 
condensed acetone 66 is recycled. A portion 68 of the recycled acetone 66 
is introduced into intermediate vessel 32 while portion 70 is mixed with 
stream 22. The non-evaporated cleavage products 72 are removed from 
evaporator 56 and cooled in heat exchanger 74 and passed as 76. For 
acetone added to the first and second stages, crude acetone from the 
distillation stage end-products of acetone columns (not shown) may be 
used. 
In the first and second stages of the process along with the desired 
products of the process such as phenol, acetone and AMS, undesired 
byproducts such as AMS dimers and complex phenols are formed in the 
reactors. 
The formation of byproducts is considered as occurring by the conventional 
carbon and ion mechanism of acidic and catalytic reactions, i.e. the 
products are protonized by the AMS double bond to form carbcationite "A" 
##STR1## 
and further on the conversion of "A" into complex phenols and AMS dimers. 
##STR2## 
However, it has now been discovered that the reactive particle is not 
carbony ion but formed oxony ion (B): 
##STR3## 
When phenol and DMBA react with this oxy ion, AMS dimers and complex 
phenols are formed. Therefore, the reactive particle is not AMS but a DMBA 
molecule. 
The determined reaction mechanism invited further investigation of the 
conditions of the reaction of DMBA conversion into AMS and DCP. In fact 
the process equilibrium is recovered: 
##STR4## 
Two important factors, such as solvent composition (i.e. the product 
composition with regard to the process) and temperature, simultaneously 
influence the equilibrium between the first and second reactive particles. 
Having determined the reaction mechanism thereof, we reexamined the 
conditions of the reaction of DMBA conversion in the DCP reactor. 
The shifting of the above equilibrium results in a three to four fold 
decrease of the amount of unreacted DMBA and the formation of undesired 
byproducts. It also results in an AMS yield of 85-89.7% of theory under 
the selected conditions of DMBA and DCP conversion in the second stage of 
the process. Further, the decrease of DMBA content at the DCP reactor 
outlet results in a reduction of the amount of undesired products formed 
in the distillation columns from about 15-17 kg/t phenol to about 8-10 
kg/t phenol that is equal to the cumene consumption coefficient decrease 
by about 7-8 kg/t that is equivalent to economization of initial cumene 
product of about 80,000 kg per year for every 100,000 tons of final phenol 
product. The above-described approach of equilibrium shift in the 
direction of AMS enables reduction of chemical losses during the 
distillation stage and further enables increase in entire process 
selectivity in particular due to reduction in non-selective chemical 
losses during the distillation stage. 
Our studies show that the equilibrium DMBA .DELTA. AMS is established very 
quickly. Simultaneously, DMBA reacts to form AMS dimers and complex 
phenols. The formation rate of the dimers and complex phenols is slower 
than the first reaction but increases substantially when the temperature 
is increased. Thus, there is an adverse competition between these 
reactions in that, when the temperature is increased the equilibrium is 
shifted to desired AMS product but also, the amount of undesired products, 
such as AMS dimers and complex phenols increases. In order to minimize 
formation of dimers and complex phenols while improving the yield of AMS, 
the cleavage process in the DCP reactor is conducted in such a manner that 
the average temperature of the reaction in the DCP reactor is not 
maintained close to the maximum temperature but is preferably maintained 
such that the average temperature in the reactor or within a number of 
zones is lower for example, preferably about 15.degree. C. lower, than the 
maximum temperature reached in the reactor. On the other hand, the 
temperature should not be raised in the respective zones at too slow a 
rate since this also interferes with production of the desired end 
product. The actual temperature curve depends on the quantity of DCP and 
DMBA which is a function of the selectivity of the first stage. Higher 
concentrations of DCP shift the curve. 
It has also been found that the heat effect of the DCP cleavage is 214 
Kcal/kg. Using the determined heat release of the reaction the process of 
DCP cleavage is conducted under non-isothermal conditions as shown in FIG. 
2. 
Depending on the amount of heat generated by the cleavage products in heat 
exchanger 44 (see FIG. 1), the temperature profile in the DCP reactor may 
be different, i.e. essentially isothermal (curve T-1), non-isothermal 
(curve T-3) or an intermediate profile (curve T-2) as shown in FIG. 2. 
In spite of equal temperatures at the reactor inlet and outlet in the case 
of T-1 and T-2 (FIG. 2) and in the case of T-2 and T-3 when the average 
temperature in the reactor is the same, the final results of AMS yield are 
significantly different. The worst results are obtained for the case of 
T-1 when the temperature in the reactor 48 is almost constant (i.e. the 
conditions are isothermal). Under these conditions the AMS yield is about 
70% of theoretical. 
The best results are obtained when the process operates non-isothermally 
(see curve T-2) in plug flow reactor 48. The AMS yield is about 89.7% of 
theory. For the case of T-3 when the average temperature is equal to the 
T-2 average temperature, results intermediate between isothermal and 
non-isothermal processes are obtained: AMS yield is about 78-80% of 
theory. 
In a preferred embodiment, a thermocouple is installed in each section of 
the DCP reactor to maintain the maximal AMS yield in the DCP reactor. The 
obtained temperature profile is compared to the optimum temperature 
profile, the latter being based on the developed kinetic model. 
In the case of temperature profile fluctuations when the DCP conversion is 
incomplete or the DCP conversion exceeds the allowable value, the reactor 
water concentration is adjusted to return the temperature profile to the 
initial values, as shown in FIG. 3A. FIG. 3A depicts the dependence of the 
temperature profile on the DCP reactor conditions, while FIG. 3B depicts 
the dependence of DCP concentrations on the DCP reactor conditions. In 
both FIG. 3A and 3B, curve 1 indicates the optimum temperature profile, 
curve 2 indicates the profile under severe conditions, and curve 3 
indicates in FIG. 3A the profile during mild conditions and indicates in 
FIG. 3B the profile when DCP is converted incompletely. The "I" zone 
indicates the cleavage product heating zone. 
Under the severe conditions of curve 2, FIG. 3B, additional water is fed to 
the reactor. This decreases the acidic properties of the catalyst and 
optimizes the temperature profile. 
In the case of incomplete DCP conversion (curve 3, FIG. 3B) in the reactor, 
the amount of water fed to the reactor is decreased and the temperature in 
the heater installed before the DCP reactor is increased. This results in 
an increase in the DCP cleavage rate and allows one to obtain the required 
DCP conversion value. 
The process of the invention exhibits numerous advantages over the 
processor of the prior art. In particular, the inventive process differs 
from the process described in U.S. Pat. No. 5,254,751 as follows: 
1. The CHP cleavage process in the mixing reactors in conducted, due to the 
balanced heat generation and heat removal rates, i.e. under conditions 
which are very close to, or are substantially, isothermal. This improves 
process safety and selectivity. 
2. The DCP cleavage process in the plug flow reactor is non-isothermal at a 
controlled temperature increase from 120 to 146.degree. C. and at the DCP 
and DMBA conversion depth controlled by changing at the same time the 
water concentration in the cleavage products and the degree of sulfuric 
acid conversion into NH.sub.4 HSO.sub.4 at varying flow rates. Temperature 
is controlled by installing a thermocouple in each section of the plug 
flow reactor. The obtained temperature profile is compared to the 
temperature profile required by the kinetic model. Based on the 
temperature deviation or .DELTA. value in each section of the reactor and 
on the fluctuations, the amount of water additionally fed to the reactor, 
the temperature and the degree of sulfuric acid conversion into NH.sub.4 
HSO.sub.4 are corrected. 
3. The composition of reaction environment in the CHP decomposition stage 
and the DCP decomposition stage is materially different due to the 
addition of variable quantities of acetone in each of the mentioned 
stages. 
4. Due to the change of the composition of the reaction medium and the 
change of the algorithm of the reactor control at the second stage of the 
process the yield of desired AMS yield is increased to 85-89.7% of theory. 
The aforementioned advantages and features of the process of the invention 
are demonstrated by the following examples and are tabulated in the Tables 
1 and 2 shown below after the Example descriptions. Example 1 is a 
comparative example while Examples 2 to 11 are of the process of the 
invention. 
EXAMPLE 1 (COMATIVE) 
72 t/hr of technical CHP is fed to the reactor block comprising three 
tube-type reactors installed in series. The reactors are operated at 
pressures of 2-10 atm. The composition of technical CHP introduced into 
the reactor series is as follows: 
______________________________________ 
Component wt % 
______________________________________ 
Cumene hydroperoxide 
82.9 
Cumene 12.0 
DMBA 4.2 
Acetophenone 0.6 
Dicumylperoxide 0.3 
______________________________________ 
9976 kg of acetone per hour is added continuously to the circulating 
cleavage products according to the set algorithm (app.12,16% of the amount 
of added CHP). 
As a result of the addition of acetone, the mole ratio of the reaction 
products phenol:acetone:cumene is 1:1.42:0.22. Sulfuric acid is added 
continuously to the circulating cleavage products. The flow rate of 
sulfuric acid is 21 kg/hr, the sulfuric acid content in the reaction 
products is 250 ppm, and the flow rate of water is 2 kg/hr. 
In the first stage, the CHP conversion is maintained in the first reactor 
at 65%, in the second reactor 89.6% and in the third reactor at 94.5%. The 
temperatures in the respective reactors are maintained at 75.8.degree. C., 
72.4.degree. C. and 63.1.degree. C. 
The CHP concentration at the outlet of the first stage reactors (14, 16, 
18) is 0.21 wt.-% that corresponds to a .DELTA.T.sub.1 value of 
1.59.degree. C. in the calorimeter by which the first stage of the process 
is controlled. 
The cleavage of DCP formed in circulation loop is conducted in an adiabatic 
two section plug flow reactor. Water at a flow rate of 716.6 kg/hr is 
continuously added to the feed line to the DCP cleavage reactor to 
maintain the water concentration at the reactor outlet at 1.91 wt %. 
In DCP cleavage reactor the same composition of reaction products, i.e. the 
ratio of phenol:acetone:cumene as found in the CHP cleavage products is 
maintained. 
The second stage reactor is controlled by the temperature differential 
.DELTA.T.sub.2 which is equal to 1.34.degree. C. by the calorimeter 
installed in the line prior to the DCP cleavage reactor. The process in 
the DCP cleavage reactor is isothermal at a temperature of 99.degree. C. 
The overall process (1.sup.st and 2.sup.nd stages) is controlled by the 
temperature difference between the two calorimeters. That temperature 
difference based on the calorimeter readings is 0.25.degree. C. 
Acetone added to the reaction products at the CHP cleavage stage is removed 
in the evaporator installed after the DCP cleavage reactor. After being 
distilled in the evaporator and condensed in the cooler, the acetone is 
recycled to the CHP cleavage stage. 
To decrease non-selective losses of desired products such as phenol and 
AMS, aqueous ammonia solution is added to the evaporator to convert 
sulfuric acid into the neutral salt (NH4).sub.2 SO.sub.4. 
The AMS yield after the cleavage stage is 78.6% of theory. 
EXAMPLE 2 
72 t/hr of technical CHP having the composition as in Example 1 is 
introduced into the mixing reactors in the CHP cleavage stage. The process 
is as shown in FIG. 1. 
The CHP cleavage is indicated in reaction products wherein the mole ratio 
of phenol:acetone:cumene is maintained as 1:1.28:0.22. This corresponds to 
8 rel. % of additionally fed acetone based on technical CHP. 
The sulfuric acid flow rate is 16.6 kg/hr. The sulfuric acid concentration 
in the reaction products is 200 ppm. 
In the first reactor, a CHP conversion of 50% is maintained. In the second 
reactor, the conversion is 69.0% and 81.16% in the third reactor. The 
temperatures are 48.2.degree. C., 48.3.degree. and 49.degree. C., 
respectively. The temperature profile in the CHP cleavage reactors is 
substantially isothermal. 
The DCP cleavage is conducted in a multi-section plug flow reactor 
operating non-isothermally at a controlled temperature increase of from 
120 to 137.degree. C. Each section of the reactor is equipped with a 
system to maintain a set temperature therein. 
Water, at a flow rate of 418.9 kg/hr is added continuously to the feed line 
in the DCP cleavage reactor to maintain a water concentration at the 
reactor outlet of 1.4 wt % . 57.5 kg/hr of an aqueous 5% ammonia solution 
is added to provide a sulfuric acid conversion into NH.sub.4 HSO.sub.4 of 
50%. 
Acetone, added to the CHP cleavage stage reaction products, is removed in 
the evaporator which follows the DCP cleavage reactor. Acetone, distilled 
in evaporator and condensed in the cooler, is recycled to the CHP cleavage 
stage. To decrease non-selective losses of desired products such as phenol 
and AMS, an aqueous ammonia solution is added to the evaporator to convert 
sulfuric acid into the neutral salt (NH4).sub.2 SO.sub.4. 
The AMS yield after the cleavage stage is 85.6% of theory. 
EXAMPLE 3 
A CHP cleavage process is conducted in the same manner as in Example 2 with 
technical CHP of the following composition. 
______________________________________ 
Component Wt.-% 
______________________________________ 
Cumene hydroperoxide 
90.3 
Cumene 2.0 
DMBA 6.2 
Acetophenone 1.0 
Dicumylperoxide 0.5 
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The CHP conversion in the first reactor is 49.6%, in the second reactor is 
67.0% and in the third reactor is 78.9%. The temperatures in the reactors 
are 48.5.degree. C., 49.5.degree. C. and 50.0.degree. C., respectively. 
The DCP cleavage is performed in a multi-section plug flow reactor 
operating non-isothermally with a controlled temperature increase of from 
120 to 143.degree. C. equipped with a system of independent forced 
maintenance of set temperature in each section. 
A continuous water flow of 198.7 kg/hr is added to the feed line in the DCP 
cleavage reactor to maintain the water concentration at the reactor outlet 
at 1.4 wt %. An aqueous 5% ammonia solution is added at a flow rate of 
60.3 kg/hr to obtain a 50% conversion of sulfuric acid conversion into 
NH.sub.4 HSO.sub.4. 
The AMS yield after the cleavage stage is 85.1% of theory. 
EXAMPLE 4 
The process is conducted in the same manner as in Example 2 except that 
15.1 kg/hr of sulfuric acid is added to the circulating cleavage products 
that results in the decrease of H.sub.2 SO.sub.4 concentration in the CHP 
cleavage reactors to 180 ppm. 
The CHP conversion in the first reactor is 48.8%, in the second reactor is 
67.0% and in the third reactor is 79.6%. The temperatures are 48.4.degree. 
C., 49.1.degree. C. and 49.9.degree. C., respectively. 
The DCP cleavage is conducted in a multi-section plug flow reactor 
operating non-isothermally at a controlled temperature increase of from 
120 to 139.degree. C. The reactor is equipped with a system to 
independently maintain set temperature in each section. 
The AMS yield after the cleavage stage is 85.8% of theory. 
EXAMPLE 5 
A CHP cleavage process is conducted in the same manner as in Example 2 
except that the cleavage is conducted in the reaction products keeping the 
mole ratio of phenol:acetone:cumene as 1:1.19:0.22 that corresponds to 5 
rel. % of additionally fed acetone based on technical CHP. 
The sulfuric acid concentration in the reaction products is 180 ppm. 
The CHP conversion in the first reactor is equal to 50.0%, in the second 
reactor to 68.8% and in the third reactor to 81.7%. The temperatures are 
47.0.degree. C., 48.3.degree. C. and 48.9.degree., respectively. 
The DCP cleavage is conducted in a multi-section plug flow reactor 
operating non-isothermally at a controlled temperature increase of 120 to 
135.degree. C. The reactor is equipped with a system for independently 
maintaining a set temperature in each section. 
The AMS yield after the cleavage stage is 85.7% of theory. 
EXAMPLE 6 
A CHP cleavage is conducted in the same manner as in Example 4 except that 
the feed rate is 90 t/hr, i.e. 25% higher than in comparative Example 1. 
The CHP conversion in the first reactor is equal to 44.0%, in the second 
reactor to 67.0% and in the third reactor to 77.1%. The temperatures are 
50.0.degree. C., 50.0.degree. C. and 48.6.degree. C., respectively. 
The DCP cleavage occurs in a multi-section plug flow reactor operating 
under non-isothermal conditions at a controlled a temperature increase of 
from 120 to 137.degree. C. The reactor is equipped with an independent 
system for maintaining a pre-selected temperature in each section of the 
plug flow reactor. 
The AMS yield after the cleavage stage is 85.6% of theory. 
EXAMPLE 7 
A CHP cleavage is conducted in the same manner as in Example 4 except that 
the feed rate is 54 t/hr, i.e. 25% lower than in comparative Example 1. 
The CHP conversion in the first reactor is 50.0%, in the second reactor 
72.9% and in the third reactor 81.9%. The temperatures are 50.0.degree. 
C., 49.2.degree. C. and 49.0.degree. C., respectively. 
The DCP cleavage is conducted in a multi-section plug flow reactor 
operating in a non-isothermal condition at a controlled temperature 
increase of from 120 to 137.degree. C. The reactor is equipped with an 
independent forced maintenance system of set temperature in each section. 
The AMS yield after the cleavage stage is 85.5% of theory. 
EXAMPLE 8 
A CHP cleavage is conducted in the same manner as in Example 4 except that 
water, at a flow rate of 886.0 kg/hr, is added into the CHP cleavage 
products before being feed to the DCP cleavage reactor to keep the water 
concentration in the DCP cleavage reactor equal to 2.0 wt %. 
The DCP cleavage is conducted in a non-isothermal manner at a controlled 
temperature increase of from 129 to 146.degree. C. 
The AMS yield after the cleavage stage is 87.0% of theory. 
EXAMPLE 9 
The CHP cleavage is conducted in the same manner as in Example 7 except 
that 629.0 kg/hr of water flow is added to the CHP cleavage products 
before adding feed to the DCP cleavage to keep the water concentration in 
the DCP cleavage reactor equal to 1.7 wt %. 
The DCP cleavage is conducted non-isothermally at a controlled temperature 
increase of from 125 to 142.degree. C. 
The AMS yield after the cleavage stage is 86.4% of theory. 
EXAMPLE 10 
A CHP cleavage is conducted in the same manner as in Example 2 except that 
water, at a flow rate of 886.0 kg/hr, is introduced into the CHP cleavage 
products before adding the feed to the DCP cleavage reactor to keep the 
water concentration in the DCP cleavage reactor at 2.0 wt %. The DCP 
cleavage step is conducted non-isothermally at a controlled temperature 
increase of from 129 to 146.degree. C. 
The AMS yield after the DCP cleavage stage is 86.8% of theory. 
EXAMPLE 11 
A CHP cleavage is conducted in the same manner as in Example 9 except that 
629.0 kg/hr of water and 17280 kg/hr of acetone are added into the CHP 
cleavage products before the feed is introduced into the DCP cleavage 
reactor to keep the concentration of water in DCP cleavage reactor at 1.7 
wt % and the additional concentration of acetone in DCP cleavage reactor 
at 24% relative to the CHP introduced into the first stage. 
The DCP cleavage is conducted non-isothermally at a controlled temperature 
increase of from 125 to 142.degree. C. 
The AMS yield after the cleavage stage is 89.7% of theory. 
The results of the above examples are tabulated in the following Tables 1 
and 2. 
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Example Summary Table 1: 1.sup.st Stage - CHP Cleavage 
Tech. CHP 
Composition of Technical CHP 
CHP conversion 
Temperature 
Mole Ratio: 
Amount of 
Exp. 
Flow Rate Aceto- [H2SO4], 
in reactors, % 
in reactors, .degree. C. 
phenol:acetone: 
added 
No. 
t/hr CHP DMBA 
phenone 
Cumene 
ppm A B C A B C cumene acetone, 
__________________________________________________________________________ 
% 
1 72 82.9 
4.2 0.6 12 250 65 89.6 
94.5 
75.8 
72.4 
63.1 
1:1.42:0.22 
12.16 
2 72 82.9 4.2 0.6 12 200 50 69 81.2 48.2 48.3 49.1 1:1.28:0.22 8 
3 72 90.3 6.2 1 
2 200 49.6 67 
78.9 48.5 49.5 
50 1:1.28:0.22 8 
4 72 82.9 4.2 0.6 12 180 48.8 67 79.6 48.4 49.1 49.9 1:1.28:0.22 8 
5 72 82.9 4.2 
0.6 12 180 50 
68.8 81.7 47 
48.3 48.9 
1:1.19:0.22 5 
6 90 82.9 4.2 
0.6 12 180 44 67 
77.1 50 50 48.6 
1:1.19:0.22 5 
7 54 82.9 4.2 
0.6 12 180 50 
72.9 81.9 50 
49.2 49 1:1.19:0. 
22 5 
8 72 82.9 4.2 0.6 12 180 50 69 81.2 48.2 48.3 49.1 1:1.19:0.22 5 
9 72 82.9 4.2 
0.6 12 180 50 69 
81.2 48.2 48.3 
49.1 1:1.19:0.22 
5 
10 72 82.9 4.2 0.6 12 200 50 69 81.2 48.2 48.3 49.1 1:1.19:0.22 8 
11 72 82.9 4.2 
0.6 12 200 50 69 
81.2 48.2 48.3 
49.1 1:1.19:0.22 
8 
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EXAMPLE SUMMARY TABLE 2 
2.sup.nd Stage -- DCP Cleavage 
[DCP] 
[H2SO4], [H2O] outlet AMS 
Exp. No. ppm wt. % wt, % Temp., .degree. C. Yield, % 
______________________________________ 
1 250 1.91 0.08 99 78.6 
2 100 1.4 0.05 120-137 85.6 
3 100 1.4 0.05 120-143 85.1 
4 90 1.4 0.05 120-137 85.8 
5 90 1.4 0.05 120-137 85.7 
6 90 1.4 0.05 120-137 85.6 
7 90 1.4 0.05 120-137 85.5 
8 90 2 0.05 127-146 87 
9 90 1.7 0.05 123-140 86.4 
10 100 2 0.05 127-146 86.8 
11 100 1.7 0.05 123-140 89.7 
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The terms and expressions which have been employed are used as terms of 
description and not of limitation, and there is no intention in the use of 
such terms and expressions of excluding any equivalent of the features 
shown and described or portions thereof, it being recognized that various 
modifications are possible within the scope of the invention.