Benzene Sulphonation ProcessAlthough this process is no longer in common use, some understanding of it will make the benefits of newer processes more obvious. The process involves several steps, but the overall reaction is:

It is one of the oldest methods of manufacture of phenol. Benzene sulphonic acid is first prepared by passing vapour of benzene into concentrated sulphuric acid is about 150-170°c.the water formed during sulphonation process is distilled out because sulfuric acid gets diluted and conditions accelerates backward reaction of the process. Benzene sulphonic acid should be neutralized by reacting it with aqueous sodium sulphite to form salt of benzene sulphonic acid. The sodium salt is filtered off and then fused with caustic in a cast iron vessel at about 340-380°c in the ratio (1:3) for about 5-6 hours. As a result, sodium phenate is formed. The melt is cooled, extracted with water and then acidified with sulphur dioxide. The latter is obtained as a result of neutralization of benzene sulphonic acid with sodium sulphite.the upper oily layer of crude phenol is distilled under vacuum to get pure phenol. The yield is about 80-90% on benzene. The lower layer contains sodium sulphite which is separated and used for the neutralization of benzene sulphonic acid.

Atom Economy

The atom economy of a reaction is found from:

The atom economy works out to be 36.7%, which is not very good! This means that considerably less than half the mass of reactants ends up in the required product, even if we assume 100% yield. In practice the yield is more likely to be in the region of 88%, giving a figure of 32.3%, barely a third of the reactant mass.

Sodium sulphite has uses in the wood pulp and paper industry, and in several other processes, but the large amount of waste produced is one of the reasons why the benzene sulphonation route is no longer used.

Rasching Process

This process was developed in Germany in 1940. Benzene is first converted into Chlorobenzene by passing a mixture of benzene vapor, hydrochloric acid vapour and air under normal pressure at about 23°c in presence of a copper iron catalyst, supported on alumina. The reaction is exothermic in nature and so the temperature is maintained constant by external cooling. The conversion .the per pass is 10%The Chlorobenzene after separation from unchanged reactants is hydrolyzed into phenol by heating with steam at about 400-500°c in presence of silica catalyst. The conversion is again about 10% per pass in this second step. Hydrogen chloride set free in the reaction is recovered and recycled. Crude phenol (97%) obtained according to the above reaction is purified by distillation under vacuum. The yield is about 75-85% on benzene. A small amount of HCl is sufficient to convert large amounts of benzene into phenol.

For 1 ton of phenol production approximately the following raw materials are required as per the process described:Benzene =        0.90 tonsChlorine =        0.82 tonsNaOH   =         0.67 tonsHCl       =          0.51 tons The main reactions which take place for this process are:1. Chlorination    C6H6 + Cl2 ---> 850C , Fe- --> C6H5Cl (Chlorobenzene) 2. Causticization    C6H5Cl +NaOH (aq)---> C6H5NaO 3. Hydrolysis    C6H5NaO + HCl(aq) ---- > C6H5OH + NaCl(aq)

A Short Process Description for Phenol Production:  Benzene which is in dry state, reacted with chlorine at the presence of  the catalyst iron or anhydrous ferric chloride at about 85 deg centigrade temperature to form Chlorobenzene in a chlorination tower, unconverted benzene is recycled and monochlorobenzene is with drawn all excess chlorine is used in neutralizer and about 10% solution of dilute caustic soda is mixed with Chlorobenzene which is reacted with caustic solution where chlorine present at the benzene ring is reacted with hydrogen and produce water vapors which is removed a tail gas. The result product diphenly oxide is pumped  to the preheater and than passed to multi tube reactor where causticization reaction occurs at the parameters 425 deg centigrade and 350 atm pressure, then the reacted mixture is passed to the neutralizer through the effluent heat exchangers.Phenol is obtained from hydrolysis occurs at the neutralizer where reaction with concentrated hydrochloric acid take place to form phenol and sodium chloride.

Sodium chloride is formed as side product, this salt is separated and send to electrolysis.

Upstream from separator is send to vacuum distillation column where phenol is stripped out. About 95% yield is obtained and diphenyl oxide is removed from the bottom of the column to recycle.

Toluene Two Stage Oxidation Process:One way to avoid the over-production of propanone associated with the cumene oxidation process, is to use a different reaction to produce phenol. About 5% of phenol is produced using the oxidation of methylbenzene (toluene), a process sometimes called the Dow and California Research Process.

This is a two-step process

Toluene in liquid phase is oxidized with air in a reactor under 40-70 p.s.i in presence of a soluble cobalt catalyst maintained at 150°c. benzoic acid and water are thus formed. The reaction is exothermic and temperature is maintained by external cooling. The crude molten benzoic acid at about 150-200°c is transfered from the reactor to distillation column, where separation of benzoic acid from un reacted toluene and produced water take place . The toluene is separated and recycled to the first oxidizing reactor. The pure benzoic acid is fed to a second reactor, where it is oxidized to phenol by air and steam under 20-25 p.s.i at 230°c in presence of cupric benzoate catalyst promoted with manganese. The reaction mass is periodically withdrawn from the second reactor into an extractor, where it is washed with water to remove unwanted tars and benzoic acid and steam are returned to second reactor. The phenol, water and unreacted benzoic acid are conducted overhead to two distillation columns in series. In the first column, crude phenol is separated from overhead and unreacted benzoic acid is recycled to the second oxidizing reactor. Pure form phenol is obtained at the second distillation column as overhead product and supply's aromatics compounds and benzoic acid as a feed to crude phenol rectification column. The yield of phenol on benzoic acid is about 75- 80%.

The advantage of the oxidation of methylbenzene is that it produces no propanone co-product and also very few impurities. It has a high theoretical atom economy, a high yield, and produced far less waste than the cumene oxidation process.

At present, however, the process is up to 3 to 4 times more energy intensive than the cumene oxidation process, and so it is not widely used.

Atom Economy

The balanced equation for the process is:

This process has an atom economy of 60.1% if phenol is the only useful product, which is a further improvement on the previous processes.

The fact that this process is not widely used reflects the fact that atom economy is, however, only one of many factors that must be taken into account.

Cumene Peroxidation process:

This process takes place in three stages:

• Producing 1-methylethylbenzene (cumene) from benzene and propene• Oxidation of 1-methylethylbenzene to hydroperoxy-1-methylethylbenzene

(cumene hydroperoxide)• Decomposition of hydroperoxy-1-methylethylbenzene to phenol

Production of 1-methylethylbenzene (cumene)

Cumene is made from benzene and propene.

The reaction is catalysed by acid, and can be carried out in either the vapour or liquid phase.Vapour phase. Solid, pelletised phosphoric acid (H3PO4) is used as a catalyst in the vapour phase reaction. Phosphoric acid is very corrosive, and disposal of waste from this process can be a problem. The catalyst cannot easily be regenerated when it reaches the end of its useful life.Liquid phase. The Lewis acid aluminium chloride (AlCl3) is used as the catalyst in the liquid phase. This is an example of a Friedel-Crafts catalyst (see catalysis site for more details) (link to cat site). It has the advantage that the reaction will take place at 100°C and normal atmospheric pressure, but corrosive waste is produced, and the catalyst cannot easily be regenerated.

In both cases the 1-methylethylbenzene (cumene) has to be separated from other products of the reaction, which will include the other addition product, propylbenzene.

Zeolite Catalysts

These newer catalysts are increasingly being used. Their advantages in this reaction are:

• The catalyst can be removed, regenerated and returned for re-use more or less indefinitely• No hazardous waste or acidic emission results from the use of zeolite catalysts• They are relatively cheap• They work with lower quality feedstock, yet produce a higher quality product• They produce a higher proportion of 1 -methylethylbenzene, and little propylbezene,

reducing energy used in purification

Oxidation of 1-methylethylbenzene (cumene)

The reaction is carried out at temperatures in the range 90 - 130ºC and pressures of 1-10 atmospheres. Careful control of acidity levels, temperature and pressure are vital as at higher temperatures, the hydroperoxide is unstable and can decompose violently.

To help reduce the risk of this happening, only 25% of the cumene is allowed to react at any one time in order to keep the concentration of the hydroperoxide within safe limits. Un-reacted cumene has to be separated out and recycled, adding to the costs.

This step also produces the major impurities of this process.

Decomposition of cumene hydroperoxide to phenol

The hydroperoxide is mixed with dilute sulphuric acid at 60 - 70ºC, to produce both phenol and propanone (acetone) as products. The decomposition of cumene hydroperoxide to phenol and acetone is often described as a cleavage reaction.

Two useful products are therefore obtained, phenol and propanone. Unfortunately this means the production of phenol is in part dependent on the demand for propanone, which is rising at a lower rate than phenol, and so in the future propanone may become a waste product.

Atom Economy

The overall process, from benzene to phenol and propanone, is:

If we assume that both phenol and propanone are desired products, and that the yield is 100%, this will clearly give an atom economy of 100% - all the atoms in the reactants appear in the products.

In practice the yield is more likely to be in the region of 90%, but even taking this into account, and assuming all the propanone is waste, still gives an atom economy of 55.7%, comparing favourably with the old sulphonation process at 36.7%.

Recycling Propanone

The Mitsui company has developed the process to include recycling the propanone. It is converted to propene, a reactant in the first step, using two further steps. Though this may help address overproduction of propanone, a five step process using hydrogen is not an ideal solution.

Benzene and purified propylene obtained from petroleum industry are mixed in liquid or vapor phase in presence of phosphoric acid on kieselguhr. As a result, cumene or iso propyl benzene is formed. The cumene thus formed is made in to the form of an emulsion with dilute aqueous sodium carbonate solution, using sodium stearate as an emulsifier. The emulsion is then oxidized in an oxidizer with air under atmospheric pressure for 3 – 4 hours in presence of catalyst, such as copper, cobalt or manganese salt. The temperature and Ph of the reaction are maintained between 160-260°c and 8.5-10.5 respectively. As a result of oxidation, cumene hydro peroxide is formed. The peroxide thus formed is then decomposed by 5-50%sulphuric acid in an acidifier at 45-65°c under pressure. As a result of decomposition, phenol (15%), acetone (9%), cumene (73%) are formed along with some α-methylstyrene and acetophenone. These separated in a separator. The cumene is recycled to be used again and phenol is either extracted or recovered by distillation. The yield is about 92%. Acetone is formed as a byproduct (0.6 lb. per lb of phenol).

Cumene production flow sheet and Process description

Outline of Cumene Production Process:• Raw material propylene and benzene are used for the production of cumene. These are

stored in the respective storage tanks of 500MT capacity in the storage yard pumped to the unit by the centrifugal pumps. 

• Benzene pumped to the feed vessel which mixes with the recycled benzene. Benzene stream is pumped through the vaporizer with 25 atm pressure and vaporized to the temperature of 243degC, mixed with the propylene which is of same and temperature and pressure of benzene stream.This reactant mixture passed through a fired super heater where reaction temperature 350degC is obtained. 

• The vapor mixture is sent to the reactor tube side which is packed with the solid phosphoric acid catalyst supported on the kieselguhr the exothermal heat is removed by the pressurized water which is used for steam production and the effluent from the reactor i.e., cumene, p-DIPB, unreacted benzene, propylene and propane with temperature 350oC is used as the heating media in the vaporizer which used for the benzene vaporizing and cooled to 40oC in a water cooler, propylene and propane are separated from the liquid mixture of cumene, p-DIPB, benzene in a separator operating slightly above atm and the pressure is controlled by the vapor control value of the separator, the fuel gas is used as fuel for the furnace also. 

• The liquid mixture is sent to the benzene distillation column which operates at 1 atm pressure, 98.1% of benzene is obtained as the distillate and used as recycle and the bottom liquid mixture is pumped at bubble point to the cumene distillation column where distillate 99.9% cumene and bottom pure p-DIPB is obtained. The heat of bottom product p-DIPB is used for preheating the benzene column feed, All the utility as cooling water, electricity, steam from the boiler, pneumatic air are supplied from the utility section

•

The reactions for cumene production from benzene and propylene are as follows:MAIN REACTION:              C3H6    +     C6H6             →    C6H5-C3H7

                                            Propylene   Benzene                CumeneSIDE REACTION:               C3H6      +    C6H5-C3H7   →        C3H7-C6H4-C3H7

                                            Propylene    Cumene               Diisopropylbenzene (DIPB)

Flow sheet of cumene manufacturing from benzene and propylene:

Description: Cumene is produced in large scale plants as intermediate for the phenol manufacturing; it is used as raw material for obtaining phenol and acetone. Cumene is produced by reacting benzene and propylene.

Well this reaction can be occurred in liquid and gas phases, but high conversion are obtained at gas phase reactions, catalyst like solid phosphoric acid are replaced by zeolites and the catalytic conversion reaction are held in shell and tube reactors rather than packed fixed bed reactors. Cumene process reaction is exothermic in nature so a complex shell and tube reactor designs are not sufficient for energy conversion, tremendous research work is involved in design a rector of Cumene production from benzene and propane. For 300 tons per day cumene production outline of process which uses a solid phosphoric acid as catalyst. As the flow sheet explains the process of a steady state system which is a continuous process and energy efficient.

Cumene plant consist of the following sections: Storage and pumping section: Benzene (99.9%) and propane (95%) are stored in liquid state in storage tanks and propane is stored in sphere. Benzene excess reactant is mixed in the

Temperature,Pressure and Flow rates of the Cumene Process Flow sheet

circulation tank where propane is added to the stream line of the feed inlet to the cascade of heat exchangers.

Preheating and vaporization section: Benzene and propane are mixed with the 2:1 ratio and fed to preheating section where a continuous series of heat exchanger are used to heat up the feed mixture with the effluents form the Cumene reactor. Finally after the heat exchanger a fired heater is used to vaporize and raise the temperature of the mixture to the reaction condition temperature. Pressure is maintained by the compressors from pumping section 

Reactor section: A shell and tube reactor is designed as such to with stand the pressure up to 25 atm and 350 degree centigrade the reactor tube are filled with catalyst and the feed is charged from the top and gas reacts and pass over the catalyst bed with 99% conversion of propylene and outlet stream is sent to the recycle and purification section, where side reaction will generate compounds like di- iso propylbenzene (DIPB).

Separation and purification section: Unreacted benzene is separated in a distillation column from the effluent obtained from the reactor and the recovered benzene is recycled to the feed stream, di- isopropylbenzene which formed as by product is separated a sieve tray distillation column which is of 99 percent pure.•  

Disadvantages of using solid phosphoric acid (SPA) Process1. Lower activity2. Catalyst non-regenerability3. Unloading of spent catalyst from reactor difficult4. Relative high selectivity to hexyl benzene5. Significant yield of DIPB Disadvantages of using Aluminum chloride as catalyst1. High corrosion2. Environmental hazard3. Washing step for catalyst removal

CURRENT INDUSTRIAL CUMENE PRODUCTION PROCESS:Cumene is an important chemical in the present industrial world and its uses are steadily increasing. The process followed for the production of cumene is the catalytic alkylation of benzene with propylene and now a days zeolite based catalysts are used in place of the normal acid based catalysts due to added advantages. Cumene production process has been greatly studied and the reaction mechanism and the reaction kinetics have been specified by many researchers. Both experimental as well as computer based simulation and optimization studies have been carried out by various researchers.

Q-Max process for cumene productionThe Q-Max ™ process converts a mixture of benzene and propylene to high quality cumene using a regenerable zeolite catalyst. The Q-Max ™ process is characterized by a exceptionally high yield, better product quality, less solid waste, decrease in investment and operating costs and a corrosion free environment. The Q-Max ™ process developed by UOP uses QZ-2000/ QZ-2001 catalyst which is a variant of β - zeolite.

Q-MAX™ PROCESS DESCRIPTION FOR CUMENE PRODUCTION:

The Q-MAX™ process provides a very good cumene yield and quality. The QZ-2000 zeolite based catalyst utilized for the Q-MAX™ process which operates with a low flow rate of benzene and hence investment and utility costs are reduced greatly. QZ-2000 is non-corrosive and regenerate-able. Compared to other zeolite based cumene technologies, the QMAX ™ process provides the highest product quality and great stability. Impurities in the fee have less effect

 The alkylation reactor is divided into four catalytic beds present in a single reactor shell.The fresh benzene feed is passed through the upper-mid section of the depropanizer column to remove excess water and then sent to the alkylation reactor. The recycle benzene to the alkylation and transalkylation reactors is drawn from the benzene column. This mixture of fresh and recycle benzene is charged through the alkylation reactor. The fresh propylene feed is split between the catalyst beds and is fully consumed in each bed. An excess of benzene helps in avoiding formation of poly alkylation and reduce the effect of olefin oligomerization. 

As the chemical reaction occurs at exothermic condition, the temperature increase during the alkylation reaction is controlled by the reactor effluent. The temperature of inlet stream from the catalyst beds is further  maintained to the designed  temperature by  the circuit reactor effluent passing tubes which are cooled  by the  side stream heat exchangers between the beds. Reacted effluent from the chemical reactor is fed to depropanizer column which separates  the propane and  excess water. The bottoms stream of the depropanizer column is fed to the benzene distillation column where excess benzene is collected  at  top of the column and recycled to the process fed stream. 

The benzene distillation column bottom stream fed to the cumene rectifying column where cumene is recovered overhead. The cumene rectifying column bottom product  is diisopropylbenzene (DIPB), and fed to the DIPB rectifying column.  The DIPB stream is  recycled to increase the conversion to the transalkylation reactor. The DIPB column bottom products contains of heavy aromatic by-products, which are  blended into fuel oil. High pressure steam is used as heating medium to the fractionation columns.

The recycle DIPB from the overhead of the DIPB column combines with a portion of the recycle benzene and is charged downflow through the transalkylation reactor. In the transalkylation reactor, DIPB and benzene are converted to more cumene. The effluent from the transalkylation reactor is then sent to the benzene column. The new QZ-2001 catalyst is utilized in the alkylation reactor while the original QZ-2000 catalyst used for  the transalkylation reactor. Catalyst life time is about 2–4 years. 

The Q-Max™ process typically produces near equilibrium levels of cumene (between 85 and 95 mol %) and DIPB (between 5 and 15 mol %). The DIPB is separated from the cumene and is reacted with recycle benzene at optimal conditions for transalkylation to produce additional cumene.

REACTION  MECHANISM AND KINETICS OF CUMENE PRODUCTION:

The following reaction mechanism are proposed for the alkylation of benzene for production  of cumene. The major reactions taking place are alkylation and trans-alkylation. Side reactions which take place are isomerisation and dis-proportionation. The reaction mechanism and kinetics may vary depending on the catalyst used. The reaction can occur in presence or absence of carbonium ion intermidate.

The reation kinetic data is obtained based on the specific catalyst used for the reaction, for example phosphoric acid catalyst and the reaction , 

Propylene + Benzene -----> Cumene

Specific Rate constant= k= 2.8X10^7

Activation energy = E = 104174 KJ/kmol 

Rate of reaction  = specific rate constant X Concentration of Benzene and Propylene

                          = k .Cb Cp 

Trans-Alkylation reaction:

The reaction rate constant          k  =  6.52 X 10-3 exp(27240/RT)

This equilibrium data for trans-alkylation reaction is obtained for modified Zeolite beta catalyst.

Equipment wise Material Balance for Cumene Production from Benzene and Propylene, Energy balance

Approximate calculation of material balance for Cumene production process from Benzene and Propylene based on the Flow sheet: used for production of 300 tons/day of cumene.

EquipmentBenzene feed

pumpPropylene feed

pump Benzene column Benzene feed

Benzene fresh feed Propylene -propane

Recycle benzene

Benzene mixed feed

Mw

kmole kg kmole kg

kmole kg

kmole kg

BENZENE78

107.52 8387.09

114.24 8911.28

221.77 17298.4

PROPYLENE

42

112.00 4704.29 0

PROPANE44 5.89 259.38 0

CUMENE

120 2.21 266.08 2.21 266.088

DIPB

162 0

TOTAL 8387.09 4963.68 9177.37 17564.5

Equipment Reactor ReactorFlash drum

top Flash drum bottom

Reactor input Reactor out put Fuel gasFeed to benzene

column

Mw

kmole kg

kmole kg

kmole kg kmole kg

BENZENE78

221.77 17298.38

114.24 8911.28 114.24 8911.28

PROPYLENE

42

112.00 4704.298 1.119 47.038

1.119 47.03 0

PROPANE44 5.89 259.38 5.89 259.38

5.89 259.38 0

CUMENE

120

2.212 265.52

106.379 12765.5 106.37 12765.52

DIPB 1 0 0 3.360 544.35 3.360 544.35

62

TOTAL 22527.59 22527.5 306.42 223.98 22221.17

EQUIPMENT WISE ENERGY BALANCE OF 300 TON/DAY CUMENE PRODUCTION PLANT Benzene feed vaporizer:

Equipment Benzene column top Benzene column top Cumene column topCumene column

bottom

Distilled benzene Feed to Cumene column Cumene product DIPB by-product

Mw kmole kg kmole kg kmole kg kmole kg

BENZENE78

114.2473 8911.289

PROPYLENE

42 0

PROPANE44 0

CUMENE

120

2.21274 265.5288

104.1667 12500.00

104.16667 12500

DIPB

162 0

3.360215 544.35483 0.10426 16.89012

3.255955 527.465

TOTAL 9176.818 13044.35487 12516.89 527.465Stream of mixed feed of benzene and cumene is feed to vaporizer with 40 oC at 25 atm.

Component Mol wt kmole Kg mole fraction mass fraction

BENZENE 78 221.7742 17298.39 0.990101 0.984851

CUMENE 120 2.2174 266.088 0.009899 0.015149

TOTAL 223.9916 17564.48 1 1  The bubble point and dew point of mixture are found by using Antoine equation, vapor pressure is calculated at various temperatures to find saturated temperature 

pi xi P yi= pi xi /P yi P yi P/ pi

BENZENE 2587.637 0.99 2533.125 1.011305 2507.794 0.969144

CUMENE 660.4975 0.01 2533.125 0.002607 25.33125 0.038352

∑ 1.013912 1.007496 Where, P is total pressure

Pi is vapor pressure at 243 oC. So, at 516 k the mixed feed will be vaporized. Heat required for vaporize =313 int 516(C dT) + latent heatLatent heat of benzene = 23,773.63 kJ/kmoleLatent heat of cumene = 30919.2 kJ/kmoleAverage heat capacity of benzene = 161.46 kJ/kmole kAverage heat capacity of cumene = 246.92 kJ/kmole k

Enthalpy of benzene = Cp ∆T + λ = 161.46 X 203 + 23,773.63 = 56,550.01 kJ/KmoleEnthalpy of cumene = 246.92 X 203+ 30919.2 = 81043.96 kJ/KmoleHeat required for the mixed feed = 0.99 X 56550.01+0.1 X 81043.96= 64088.89 kJ/Kmole=64088.89 X 223.9= 14349502 kJ = 14349.502 MJ/h Propylene feed vaporizer:                           Propylene and propane fed from tank with 25 0C at 25 atm.The stream is vaporized and heat to the temperature 2430C and mixed with benzene feed.Bubbling point and dew point of mixture is about 62.5 0CLatent heat of propylene = 17229.4 kJ / hLatent heat of propane = 17611.41 kJ / hAverage heat capacity of liquid propylene =123.51 and propane=125.48 Average heat of capacity of gaseous propylene = 82.86and propane=97.48

Liquid state:

propylene propane

Cp 123.51 125.48

∆T 37.5 37.5

Q (kJ/h) 4631.625 4705.5

Gas state :

propylene propane

Cp 82.86 97.483

∆T 180.5 180.5

Q (kJ/h) 14956.23 17595.6815 Heat required for propylene:17229.46+4631.625+14956.23 = 21861.08 kJ/hHeat required for propane:17611.39+4705.5+17595.075 = 39912.57 kJ/hHeat required for the feed = 117.9 (21861.08 X 0.95 + 39912.57 X 0.05)= 2683.83 MJ/h

Fired heater: Heat required for rise the temperature reactant feed to 350 0C

inlet 0C =  243 outlet  0C =         350

comp kmole/h heat capacity constants of gas mixture

n A B C D E

C3H6 112.0071 31.298 7.24E-02 1.95E-04 -2.16E-07 6.30E-11

C3H8 5.8951 28.277 1.16E-01 1.96E-04 -2.33E-07 6.87E-11

C6H6 221.7742 -31.368 4.75E-01 -3.11E-04 8.52E-08 -5.05E-12

C9H12 2.21274 10.149 5.11E-01 -1.77E-05 -2.26E-07 8.80E-11

nA nB nC nD nE

3.51E+03 8.11E+00 2.18E-02 -2.42E-05 7.05E-09

1.67E+02 6.84E-01 1.16E-03 -1.37E-06 4.05E-10

-6.96E+03 1.05E+02 -6.91E-02 1.89E-05 -1.12E-09

2.25E+01 1.13E+00 -3.92E-05 -5.00E-07 1.95E-10

 Cp= -3.26E+03 1.15E+02 -4.61E-02 -7.14E-06 6.53E-09

∆ T = 107 31725.5 9508697.667 2879866400 8.8098E+11

 Cp∆ T= -349019.239 3.65E+06 -4.39E+05 -2.06E+04 5.76E+03

∑ Cp∆ T= 2.85E+06 kJ/h 

Comparison for the methods

s.n

EXISTING  METHODS

RAW MATERIALS YIELD   PRODUCTS  COMMENTS

 1. Cumene per oxidation

Cumene,air,small quantities of H2SO4&Emulsifying agents

 92% Phenol & acetone Produces valuable co product acetone

 2. Toluene two stage oxidation

 Toluene, air, cobalt napthalate, cupric benzoate catalyst

 80% Phenol & CO2 Low costs of toluene

 3. Rasching phenol process

 Benzene, air, HCl  75% Phenol & HCl recycle

Feasible under large units

 4. Chlorobenzene caustic hydrolysis

 Benzene, chlorine,       NaOH, HCl

 95% Phenol, Nacl(aq) Economically not feasible

 5. Benzene sulfonate process

 Benzene, H2SO4,  NaOH

 87% Phenol , Na2SO3, Na2SO4

Operates on large batch cycles.