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INTRODUCTION

Benzaldehyde (C6H5CHO) is the simplest and the most industrially useful member of the family of aromatic aldehydes. Benzaldehyde exists in nature, primarily in combined form such as glycoside in Almond, apricot, cherry and peach seeds. The characteristic benzaldehyde odour of oil of bitter almond occurs because of trace amounts of free benzaldehyde formed by hydrolysis of the glycoside amygdalin. Amygdalin was first isolated in 1830 from the seed of the bitter almond sometime later Liebeg and Wohler found that when amygdalin was hydrolyzed with water and emulsion. Benzaldehyde hydrogencyanide and D Glucose were formed (2). Now presently Benzaldehyde is produced by many process like - chlorination of Toluene (liquid phase) - oxidation of Toluene (liquid phase) & (vapor phase) The hydrolysis of benzalchloride is, which is produced by side chain chlorination of toluene, is older of the two processes. Other processes includes - Oxidation of benzyl alcohol - Reduction of benzoyl chloride - Reaction of carbonmonoxide and benzene. Have been utilized in the past, but they no longer have any industrial application. (2)

There is considerable demand for chlorine free benzaldehyde as it is used in pharmaceutical industry. As multinational is being coming up the competition is been developing and major challenge faced by the industry is purity of product (free from chlorine) Oxidation builds up the chlorination process material has large demand in soap and perfume industry. Electroplating industry has great demand for benzaldehyde. Hence, benzaldehyde industry is an important raw material for many industries. The leading manufactures of Benzaldehyde in India is, Name of Company Place Indian Org ltd. Khopoli Estimated requirement of Benzaldehyde Year Quantity 1976-77 6000 Tons 1984-85 8000 Tons 1989-90 10000 Tons 1994-95 12000 Tons 1999-2000 14000 Tons

LITERATURE REVIEW


Physical and Chemical Properties:

Aromatic aldehyde has an aldehyde group attached to benzene or another aromatic substrate. They are weaker bases than the corresponding aliphatic aldehydes. Benzaldehyde is a member of the aromatic aldehyde chemical family. Formulae: C6H5CHO Physical Properties: Raw material requirement: - Toluene - Chlorine - Sodium carbonate Toluene: 1 State Liquid 2 Boiling point 110.6250C 3 Melting point -950C 4 Molecular wt 92 5 Solubility 100 parts of water 0.05 in cold. 6 Specific Heat (cal/mole 0K) 40.48 7 Heat of formation (Kcal/mole) 2.87

7 Heat of formation (Kcal/mole) 2.87 8 Special gravity at 200C 0.866 Chlorine: 1 State Liquid 2 Boiling point -34.60C 3 Melting point -101.60C 4 Molecular wt 71 5 Solubility 100 parts of water 0.57 in hot 46 in cold. 6 Specific Heat (cal/mole 0K) 8.28 7 Heat of formation (Kcal/mole) 0 8 Special gravity at 200C 1.56 Sodium Carbonate: 1 State Solid 2 Boiling point ----- 3 Melting point 8510C 4 Molecular wt 106 5 Solubility 100 parts of water 7.1 in hot 48.5in cold.

5 Solubility 100 parts of water 7.1 in hot 48.5in cold. 6 Specific Heat (cal/mole 0K) 28.9 7 Heat of formation (Kcal/mole) -275.9 8 Special gravity at 200C 2.533

Physical Properties of Benzaldehyde: Property Value 1 Molecular formula C7H6O2 Molecular weight 106.12 3 Boiling Point179 0C @760mmHg 4 Melting point, 0C -260C (-150F) 5 Flash point, 0C Closedcup-640C(1480F) Open cup - 740C (1650F) 6 Specific Gravity 1.046 7 Refractive Index 1.5455 @ 17.60C 8 Auto ignition temp,0C 192 or (3780F) 9 Vapor Pressure 10mm Hg @ 620C 60mm Hg @99.60C 100mm Hg @ 112.50C 400mm Hg @ 154.10C 10 Vapor Pressure Equation LogP = A-B/(T+C) Where A= 6.6153, B= 1277 C= 164 & P= mmHg & Tin 0C 11 Sp. Heat (liquid), J/g 0K 1.615 @ 250C 12 Solubility in water, wt. 0.6 @ 200C 13 Solubility of water in, wt % 1.5 @ 200C

13 Solubility of water in, wt % 1.5 @ 200C 14 Viscosity, Centipoise 1.4 @ 250C 15 Standard Heat of combustion, KJ/g -31.9 16 Heat of formation, KJ/mole - 88.89 17 Latent Heat of Vaporisation, J/g 362

CHEMICAL PROPERTIES: Benzaldehyde react with various compounds, because of its reactive aldehyde hydrogen, its carbonyl group and the benzene ring, some of which are summarized below (2) 1) Aldehyde Hydrogen Reaction: The hydrogen of the aldehyde group is readily oxidized to OH, forming benzoic acid. Benzaldehyde Benzoic Acid

2) Chlorine can replace the hydrogen to produce Benzyl chloride (Benzaldehyde) (Benzoyl Chloride) 3) Cannizaro Reaction: Benzaldehyde is both oxidized and reduced to form benzoic acid (as a benzoate salt) and Benzyl alcohol. + (Benzaldehyde) (Benzoate Salt) (Benzyl Alcohol) 4) Alkali metal cyanides catalyse the condensation of benzaldehyde Benzoin. 5) Addition of hydrogen cyanide: Mandelonitrile is formed by the addition of hydrogen cyanide to the carbonyl double bond. (Benzaldehyde) Mandelonitrile

6) Hydrogenation of carbonyl group yields Benzyl alcohol (Benzaldehyde) 7) Condensation of carbonyl group compounds with ammonia or primary amines, fives Schiff bases, also known as Amines, which on hydrogenation results in amines such as Benzyl amine and Di benzyl amines. Dibenzyl Amine.

2.3 MANUFACTURING PROCESSES (18):

There are several methods for the manufacturing of benzaldehyde. Benzaldehyde is manufactured by the following process. 1. By oxidation of toluene in vapour or liquid phase. 2. By chlorination of toluene in liquid phase. 2.3.1 Oxidation of toluene: The partial oxidation of toluene with oxygen to give benzaldehyde can be carried out in two phases. a. Oxidation of toluene in vapour phase. b. Oxidation of toluene in liquid phase. 2.3.1.a. Oxidation of toluene in vapour phase In the vapour phase the oxidation is carried out by passing toluene phase. Together with oxygen in a gaseous mixture such as air, through a catalyst bed in a tube bundle or fluidized bed. Reactor at a temperature of 250 – 6500C. The reaction is highly exothermic and effective cooling is necessary. C6H5CH3 + O2 C6H5CHO + H2O ? H = - 373.04 KJ/mole C6H5CH3 + 3 C2O2 C6H5COOH + H2O ? H = - 680.35 KJ/mole C6H5CH3 + 902 2CO2 + 4H2O ? H = - 3912.14 KJ/mole

It is advisable to dilute the mixture of toluene vapour and oxygen containing gas with unreactive gas, such as water vapour, nitrogen or carbon dioxide. The benzaldehyde yield is favoured by a low conversion rate (1020%) per pass. A short residence time (0.1-1.05) and a precise adjustment of the amount of oxygen. It is only 40-60% at the theoretical yield based on toluene. A recently published process uses a mixed oxide catalyst that has silicon dioxide as a carrier and contains uranium, copper, iron, phosphorus, tellurium and lead in addition to molybdenum. At toluene consumption of 35-50% per pass the selectivity of the benzaldehyde formation at a reaction temperature of 475-5500C is 40-70%, catalysts based only on mixed oxides of molybdenum and uranium require reaction temperature at around 6000C. The reaction rate constant is of relatively low order of magnitude (10-4 1/s g or catalyst) as found by downie and darshan for V2O5 + K2SO4 catalyst. Gas film resistance can be overcome by passing the reactants gas stream at high velocity. Pore diffusional resistance is eliminated by using smaller size catalyst particles. Under these conditions downie reported the following reaction rate constant using the Hinshelwood model. KaKtCoCt R = KoCo + NKtCt N = 1.35

Ka = 1.39 x 10-4 at 3500C Kt = 2.38 x 10-4 at 3500C 2.3.

1.b Oxidation of toluene in liquid phase The oxidation of toluene in the liquid phase by oxygen in the form of air or other gaseous mixture. This is carried out at 80 – 2500C, preferably in the presence of Cobalt, Nickel, Manganese, Iron or Chromium compound. A pressure at which the reaction medium remains liquid is chosen. Alkali, alkaline earth and tertiary alkyl hypochlorites have been used as oxidation promoters in place of the usual bromides. These promoters may cause corrosion. The selectivity of the benzaldehyde formation is improved by liquid phase oxidation of the toluene with oxygen in the presence of a phosphoric acid-palladium catalyst that also contains certain phosphorus, sulfur or nitrogen modifier for oxygen consumption at 63%, the yield of benzaldehyde is 41%. Disadvantages of oxidation process (27) The oxidation of toluene in the gas phase produces maleic anhydride, citraconic anhydride, phthalic anhydride, anthraquinone, cresol, acetic acid and other compound. The benzaldehyde yield is favoured by a low conversion rate (10-20%) per pass. It is only 40-60% of the theoretical yield based on toluene. The oxidation of toluene in vapour phase requires reaction temperature at 6000C and reaction is highly exothermic. Benzaldehyde produced by oxidation of toluene often contains small amount of impurities that are difficult to remove by distillation and which discolour the product. 2.3.2 Chlorination of toluene in liquid phase (18) This is the most common process, which is used for preparation of high purity product, which can be shown in fig. The main reactants involved in this process are toluene, chlorine gas and sodium carbonate. The technical preparation of BZCHO proceeds along these lines. Toluene is first converted to Benzylchloride by passing chlorine gas into chlorinator. The reaction temperature is 1150C in the liquid phase chlorination route. The hydrogen chloride evolved is recovered by adsorption in water. U.V.light C6H5CH3 + Cl2 C6H5CH2Cl +HCl U.V.light C6H5CH2Cl + Cl2 C6H5CHCl2 +HCl U.V.light C6H5CHCL2 + Cl2 C6H5CCl3 + HCl

The chlorinated mass pumped into vacuum distillation which is operated at 70mm Hg. Top product contain BzCl and some amount of BzCl2 which is recycled to chlorinator. Bottom product contain BzCl2 and BzCCl3, bottom product goes to hydrolyzer. The hydrolysis of benzylchloride which is readily obtainable by side chain chlorination of toluene. It can be carried out in alkaline medium hydrolysis under basis condition can be carried out with a small excess at 15% sodium carbonate solution at 1380C. C6H-5CHCL2 + Na2CO3 + H2O C6H5CHO + 2NaCl + H2O + CO2 C6H-5CHCL3 + 2Na2CO3 + H2O C6H5COONa + 3NaCl + H2O + 2CO2 The hydrolysis of benzyl chloride is carried out in presence benzaldehyde (90%). Sodium benzoate is formed as an inorganic layer, which is, removed and use for benzoic acid production. The organic layer is vacuum (70 mm Hg) distilled. The top product contains (95%) pure benzaldehyde which is condensed is the main product. 2.4 Discussion The physical and chemical properties of the raw material and the product are discussed in detail. Benzaldehyde finally obtain from oxidation process is not pure as much as obtain from chlorination of toluene. In pharmaceutical industry the purity of benzaldehyde (free from chlorine) is very much important. From the literature review we can say that the chlorination process is economically feasible for high purity of product to be manufactured.

MATERIAL BALANCE The kinetics aspects of the process were discussed and now we shall carry out the material balance on a 600 tpa plant of Benzaldehyde. Material balance is based on the law of conservation of mass i.e. total mass input is equal to total mass output. It gives us the amout of compounds needed and specific amount of products to be formed (8). Section 1 gives the calculation of the material balance of the plant. The summary of the culculation is given in table 4.1 to 4.5 in section

2. 4.1 CALCULATIONS OF MATERIAL BALANCE The material balance for the plant is done as follows capacity of plant 600 tpa. Assuming no of working days 300 days per year. - Reactions involved are: Blue light Toluene Benzyl chloride Blue light Benzal chloride Blue light Benzal chloride Benzotrichloride. R Toluene - RXR1 Benzyl cl - RXR2 Benzal Cl2 - RXR3 D F M P Bzcl2 Bzcl3 F = Fresh Toluene feed. R = Recycle Stream. M= Mixed Stream. Let, XR1 be mole fraction of toluene in Recycle Stream. XR2 be mole fraction of Benzylchloride in Recycle Stream. XR3 be mole fraction of Benzalchloride in Recycle Stream. Assumption – There is no Benzotrichloride in Recycle stream, that is all Benzotrichloride is separated by distillation. – Toluene in fresh feed is 100% pure. Now F+R = M {Overall mole Balances} Total Toluene entering the chlorinator. = F + RXR1 Total Benzyl chloride entering the chlorinator = RXR2 Total Benzalchloride entering the chlorinator = RXR3 Toluene + Cl2 Benzyl chloride + HCl ----- i Toluene + 2Cl2 Benzalchloride + 2HCl ----- ii Toluene + 3Cl2 Benzotrichloride + 3HCl ----- iii Assuming that in 1st Rxn 55% of Toluene is consumed, in 2nd Rxn 22% of Toluene is consumed in 3rd Rxn 1% of total toluene is consumed and the conversion of toluene is 78%, and no nuclear product is being formed in chlorinator. TOLUENE BALANCE: Toluene in product (P) = Toluene unreacted. Toluene in product (P) = 0.22 (F + RXR1) ---------------- 1 Assuming that 98% of toluene is separated by distillation and recycled. ? Toluene in recycle = 0.98 [ 0.22 (F + RXR1)] = 0.2156 [F + RXR1] ---------------- 2 But toluene in recycle = RXR1 ---------------- 3 Equating equation 2 and 3, we get, RXR1 = 0.2156 [F + RXR1] RXR1 = 0.2748 F (1-0.2156) RXR1 = 0.2156 F 0.7844 RXR1 = 0.2156 F RXR1 = 0.2748 F ---------------- 4 ? Total toluene coming to chlorinator = F + RXR1 = F+ 0.2748 F = 1.2748 F ---------------- 5

BENZYLCHLORIDE BALANCE: Benzyl chloride in recycle stream = RXR2 ---------------- 6 Total Benzyl chloride entering chlorinator = RXR2 ---------------- 7 Now Benzyl chloride formed by Rrn (ii) Toluene + Cl2 Benzalchloride + HCl. Since 55% of toluene entering is consumed in above reaction. Benzyl chloride = 55% of toluene entering = 0.55 [ 1.2748 F] by equation 5. = 0.70114 F. ---------------- 8 ? Assuming 50% of Benzyl chloride in recycle stream, reacts with chlorine to form Benzalchloride by following stoichometry. Benzylchloride + Cl2 Benzalchloride + HCl. ?Benzalchloride formed by above reaction = 0.5 (RXR2). ---------------- 9 ?Unreacted Benzyl chloride of recycle stream = RXR2 – [0.5(RXR2)] = 0.5 RXR2 ---------------- 10 ??Benzyl chloride in product(P)? = ?Benzalchloride formed by reaction by equation (8)? +? Unreacted of recycle stream by equation (10).? = 0.70114 F + 0.5 RXR2 ------------- 11 Assuming 97% of Benzyl chloride is separated by distillation and recycled. ?Benzyl chloride in recycle = 0.97 [0.70114 F + 0.5 RXR2] = 0.680 F + 0.485 RXR2 ------------- 12 But Benzyl chloride in recycle = RXR2 ?Equating equation 6 and 12 we get. RXR2 = 0.680 F + 0.485 RXR2 (1-0.485) RXR2 = 0.680 F. 0.515 RXR2 = 0.680 F. RXR2 = 0.680 F / 0.515. ? RXR2 = 1.32 F ------------- 13 This is total Benzyl chloride coming to chlorinator.

BENZALCHLORIDE BALANCE: Benzalchloride in recycle stream = RXR3 RXR3 F Benzalchloride in feed is zero, i.e.XF2 = 0 Total Benzalchloride entering chlorinator = RXR3 Benzalchloride formed by reactions. (i) From toluene chlorination: Toluene + 2Cl2 Benzalchloride + 2HCl Since 22% of Toluene entering is getting consumed in above reaction. ?By stoichometry Benzalchloride formed by above reaction. = 0.22 [Toluene Entering] = 0.22 (1.2748 F) by equation (5) = 0.280456 F ------------- 14 (ii) Chlorination of Benzyl chloride ( in recycle): Since 50% of Benzyl chloride in recycle stream is chlorinated to form Benzalchloride by following reaction. Benzyl chloride + Cl2 Benzalchloride + HCl. ? Benzalchloride formed = 0.5 (Benzyl chloride in recycle) = 0.5 (RXR2) ?RXR2 = 1.32 F from equation (13) ?Benzalchloride formed = 0.5 (1.32 F) = 0.66 F ------------- 15 Assuming that 15% of Benzal chloride in recycle shown is getting reacted with chlorine to form Benzotri chloride. ? Total Benzal chloride in product (P) = (Benzal chloride in recycle) + (Benzal chloride formed by reaction.) – 15% (Benzal chloride in recycle). = RXR3 + (0.66 F + 0.280456 F) – 0.15 (RXR3) Total Benzal chloride in product = 0.85 RXR3 + 0.940456 F. ------------- 16 Assuming that 90% of Benzal chloride is removed by distillation 10% of Benzal chloride comes in the recycle stream. ? Benzal chloride in recycle stream = 0.1 [ Benzalchloride coming out of reactor]. = 0.1 [ 0.85 RXR3 + 0.940456 F] = 0.085 RXR3+0.0940456 F --------- 17 But Benzal chloride in recycle stream = RXR3 --------- 18 ?Equting equation (17) and (18) we get, RXR3 = 0.085 RXR3 + 0.0940456 F RXR3 = 0.085RXR3 + 0.0940456 F (1- 0.085) RXR3 = 0.0940456 F. ? RXR3 = 0.10278 F. --------- 19 This is Benzal chloride in recycle stream = RXR3 = 0.10278 F. Now, Benzal chloride obtained ofter distillation: = 90% [Benzal chloride in the Product(P) ] = 0.9 ( 0.85 RXR3 + 0.940456 F) = 0.9 (0.85 (0.10278 F) + 0.940456 F) = 0.9 (0.08736 F + 0.940456 F) = 0.9 ( 1.0278 F) ?Benzal chloride obtained after distillation = 0.92502 F. --------- 20

BENZOTRICHLORIDE BALANCE: Benzotri chloride in recycle stream = 0 Benzotrichloride in feed is =0 ? Benzotrichloride entering the reactor is zero. Benzotrichloride formed by reaction: i) By chlorination of Toluene : Toluene + 3Cl2 Benzotrichloride + 3HCl. ?1% of Toluene entering is getting consumed by above reaction. ?By stoichometry Benzotrichloride formed = 0.01 [Toluene entering] = 0.01 [ 1.2748 F] by equation (5) = 0.012748 F. --------- 21 ii) By chlorination of Benzal chloride: Benzal chloride + Cl2 Benzotrichloride + HCl. Since, 15% of Benzal chloride in recycle stream is getting consumed by above reaction. ?Benzotrichloride formed = 0.15 [ Benzal chloride in recycle] = 0.15 [RXR3] = 0.15 [0.10278 F] = 0.015417 F. --------- 22 ?Total Benzotrichloride formed = 0.012748 F + 0.01541 F = 0.028165 F. --------- 23 ?Total Benzotrichloride in product (P) =0.028165 F. Assuming all Benzotrichloride is separated by distillation and there is no Benzotrichloride in the recycle stream.

HCL BALANCE: HCl in recycle stream = 0 HCl in F = 0 ? HCl entering the reactor = 0 HCl formed by the reactions: i) By chlorination of toluene to Benzyl chloride. Toluene + Cl2 Benzyl chloride + HCl. Since, 55% of Toluene entering is consumed is above reaction. Therefore by stoichometry. ?HCl formed = 55% [Toluene entering] = 55 [ 1.2748 F] = 0.70114 F. --------- 24 ii) By chlorination of Toluene to Benzal chloride: Toluene + 2 Cl2 Benzal chloride + 2 HCl. Since, 22% of Toluene entering is getting comsumed in above reaction. ? By stoichometry HCl formed = 2 [0.22[1.2748 F]] = 2(0.280456 F) = 0.560912 F. --------- 25 iii) By chlorination of Toluene to Benzotrichloride: Toluene + 3Cl-2 Benzotrichloride + 3 HCl. Since, 1% of Toluene entering is getting consumed in above reaction. ? By stoichometry HCl formed = 3 [ 0.01[1.2748 F]] = 3 (0.012748 F) = 0.038244 F. --------- 26 iv) By chlorination of Benzyl chloride (recycle stream) to Benzal chloride: Benzyl chloride + Cl2 Benzal chloride + HCl. ?50% of Benzyl chloride in recycle is getting reacted by above reaction. ?By stoichometry HCl formed. = 0.50 [ Benzyl chloride in recycle] = 0.50 [ RXR3] = 0.50 [ 1.32 F] = 0.66 F. --------- 27 v) By chlorination of Benzyl chloride (recycle stream) to Benzotrichloride: Benzal chloride + Cl2 Benzotrichloride + HCl. ?15% of Benzal chloride is getting consumed by above reaction. ?By stoichometry, HCl formed. = 0.15 [ Benzal chloride in recycle] = 0.15 [ RXR3] = 0.15 [ 0.110278 F]. = 0.015417 F. --------- 28 ?Total HCl formed = 0.70114 F + 0.560912 F + 0.038244 F + 0.66 F + 0.015417 F = 1.975713 F. --------- 29 We can obsorb these HCl in water to give 30% HCl solution (by weight). Therefore, HCl on weight basis is = 1.975713 F x 36.5 = 72.1135 F (weight basis) The water required can be calculated by the following. Now, 72.1135 F = 0.3 ( Toluene solution) Toluene solution = 72.1135 F = 240.378 F. 0.3 Water required, = 0.7 (240.378 F) = 168.2648 F (weight basis) ? Water required = 168.2648 F (weight basis) CHLORINE BALANCE: By stoichometry of reactions we know that, chlorine reacted ? HCl formed. Since, HCl formed = 1.975713 F ?Chlorine reacted = 1.975713 F Note: Assuming all chlorine fed is getting reacted as the equation stated before.

MATERIAL BALANCE FOR DISTILLATION: The chlorinated mass obtained, has to be purified by distillation. The bottom product contains mostly Benzal chloride and Benzotrichloride. Feed to distillation column = product (P) from chlorinator. R D F P I S T W (P) = (Toluene) + (Benzyl chloride) + (Benzal chloride) + (Benzotrichloride) Toluene Balance : Toluene in P = Toluene in R + toluene in W. 0.22 (F + RXR1) = RXR1 + WT 0.22 (F + 0.2748 F) = 0.2748 F + WT 0.280456 F – 0.2748 F = WT 0.005656 F = WT Benzylchloride Balance: Benzyl chloride in P = Benzyl chloride in R+ Benzyl chloride in W 0.70114 F + 0.5 RXR2 = RXR2 + WBenzylchloride 0.70114 F + 1.32 F (0.5) = 1.32 F + WBenzylchloride 0.04114 F = WBenzylchloride Benzalchloride Balance: (Benzal chloride in P) =( Benzal chloride in R)+(Benzal chloride in bottoms W) 0.85 RXR3 + 0.940456 F = RXR3 + WBenzal chloride 0.85 (0.10278 F) + 0.940456 F = 0.10278 F + WBenzal chloride 1.027819 F – 0.10278 F = WBenzal chloride ? WBenzal chloride = 0.925039 F. Benzotrichloride Balance: (Benzotrichloride in P) = (Benzotrichloride in R)+(Benzotrichloride in bottoms W) 0.028165 F = 0 + WBenzotrichloride ? WBenzotrichloride = 0.028165 F Since Benzotrichloride is not recycled. Distillation column overall material balance Feed (P) Distillate (R) Bottoms(W) Toluene 0280456 F 0.2748 F 0.005656 Benzylchloride 1.36114 F 1.32 F 0.04114 F Benzalchloride 1.027819 F 0.10278 F 0.925939 F Benzotrichloride 0.028165 F 0 0.028165 F Total 2.69758 F 1.69758 F 1.0 F P = R + W Uses: 1) The NF /FCC grade of benzaldehyde is widely used in flavors such as almond and cherry in various fragrances for soap and toiletries. 2) Benzaldehyde is a F.D.A. sanctioned synthetic flavoring substance generally recognized as safe for foods. 3) The technical grade is a versatile chemical intermediate in the manufacture of pharmaceuticals, dyes, perfumes and flavoring chemicals. 4) It is used as a Bee repellant in the harvesting of honey. 5) It is used in denatured alcohol. 6) Intermediates for numerous derivatives. 7) Chemical intermediate for aromatic alcohol. 8) It is used as a solvent for Oils, Resins some cellulose ethers, Cellulose acetate and nitrate. 9) It is used in manufacturing of Benzoic acid, pharmaceuticals, and photographic chemical. 10) Technical grade benzaldehyde is used in manufacturing of cinnamic and mandelic acids 11) Benzaldehyde is largely used as an intermediate for the manufacture of odorants and flavoring chemicals, mainly cinnamaldehyde, amyl cinnamaldehyde, hexyl cinnamaldehyde and cinnamyl alcohol. 12) Benzaldehyde is also used as starting material for pharmaceuticals (Ampicillin) and pesticides (Dibenzoquat). 13) Phenol Benzaldehyde resins have been utilized to prepare fireproof structural foam ferrocene polymers are also prepared from Benzaldehyde. 14) It is used in the production triphenylmethane green, which is obtained by condensation of benzaldehyde with dimethylaniline. 15) It is also used for extractive separation of isomeric amines. 16) Benzaldehyde most important use in organic synthesis where it is raw material for a large no of products.

PROCESS SELECTION: Benzaldehyde is an industrially the most important aromatic aldehyde. It is used in the production of dyes, pharmaceuticals and perfumeries. The physical and chemical properties of the raw material and the product are discussed in detail. Hydrolysis of benzalchloride or the partial oxidation of toluene (vapor or liquid phase) principally produces benzaldehyde. Some other process for the manufacture of benzaldehyde include the reaction of benzene and co the oxidation or dehydrogenation of benzyl alcohol and catalyzed oxidation of styrene with hydrochlorite. Benzaldehyde can also be manufactured by the hydrolysis of mixture of benzyl chloride and benzalchloride in oil HNO3 using vanadium pentoxide as a catalyst or in the presence of hexamethylene tetramine. These process have no industrial importance in the production of benzaldehyde are more likely to be used to make certain unclear substituted derivatives. The commercial process for the production of benzaldehyde are:

1) LIQUID PHASE OXIDATION ROUTE: This route involves oxidation of liquid toluene to benzaldehyde in the presence of homogeneous catalyst. Manganese dioxide with sulphuric acid has been used as the most suitable catalyst. A 14% yield of benzaldehyde has been claimed. When the cobalt is used as a catalyst at 3-atm pressure, the total conversion of benzoic acid and benzaldehyde was found to be 40%. Benzaldehyde is separated by fractional distillation. C6H5CH3(1) + O2 C6H5CHO (1) + H2O H= 92 Kcal / mole at 250C.

2) VAPOUR PHASE OXIDATION ROUTE: Vapour phase oxidation provides chloride free benzaldehyde with a minimum amount of by product formation. Toluene is directly oxidized by air in the vapour phase at atmospheric pressure in the presence of a catalyst maintained at above 4000C. In this route extensive work was carried out using different catalyst. The most selection catalyst appears to be Vanadium pentoxide promoted with potassium sulphate and promoted uranium oxide catalyst. Both catalysts given approximately 60% yields of benzaldehyde based upon toluene. There is a varying amount of by product formation during oxidation. The principle by products are Benzoic acid, carbon dioxide, Anthraquinone, carbon monoxide and water.

3) ELECTROCHEMICAL ROUTE: In a single stage process an emulsion of toluene in 60% sulphuric acid is oxidized electrolytically to benzaldehyde with lead electrodes. Mn2(SO4)3.5H2O is used as the oxygen carried with CaSO4 as the promoter. Unreacted toluene and the electrolytes are recycled. In a two-stage process, the first stage involves electrolytic oxidation of manganous sulphate to manganic sulphate paste. In the second stage, manganic sulphate is reacted with toluene in the reactor and benzaldehyde is formed. The manganous sulphate formed is regenerated electrolytically.

4) CHLORINATION OF TOLUENE: In this process chlorine is reacted with toluene in presence of light to give benzalchloride, benzylchloride as intermediate and then hydrolysed benzalchloride gives benzaldehyde. Product found from this process is chlorinated on small scale. The chlorination method is cheapest and gives chlorine free benzaldehyde. Considering the different process and studying it for manufacture of benzaldehyde do not give high percentage of yield and unwanted materials are also produced in a large amount. The electrochemical route is also expensive as it uses electricity and catalyst in large amount. There is also one process i.e. chlorination of toluene using catalyst. The catalyst used is PCL3 handling and storage of this catalyst creates problems and therefore the process is not considered. The process described here is the photochlorination of toluene, which gives a good yield. From this process we get two major by product such as 30% HCL and benzoic acid and also some sodium hypochlorate, which can be sold in market. Raw material used is chlorine comes in tonnes and therefore, this process is selected for manufacturing of benzaldehyde.

SAFETY CONSIDERATION: Planning safety is a very important aspect to be considered in the planning of setting up of a plant. The safety precautions taken by the management would lead to a better working by the labour since they would not have to worry about their safety (Ref) Safety planning can be classified as a) Identification of hazardous operations. b) Prevention and control of possible hazard which can be ensured by setting up various alarms and trip devices. The Benzaldehyde is relatively non-toxic material. The registry of Toxic Effects of Chemicals (NIOSH) lists the following data for benzaldehyde. LD 50 (orl-rat) 1300 mg/kg. LD 50 (orl-guinea pig) 1000 mg/kg. Benzaldehyde is considered a moderately toxic substance when ingested. Benzaldehyde should be handled with the good manufacturing practices of avoidance of contact, adequate ventilation, and cleanliness normally accorded the handling of solvents and other organic compounds. Prolonged exposure to the vapors of benzaldehyde should be avoided. At temp of less than 250C, saturates mixtures of air and benzaldehyde will contain less than 950 ppm benzaldehyde. Contact with the skin and eyes should be avoided. Direct contact with benzaldehyde may cause dermatitis. For chemical workers, goggles, gloves, and face shields are recommended. In the event of skin contact, the skin should be washed with soap and water. Call a physician if irritation develops. In the event of eye contact, plush the eyes for 15 minutes with large amount of water. Get immediate medical attention. Benzaldehyde has a low ignition temperature 1920C (3780F). Therefore benzaldehyde should be kept away from areas of high temp, such as uncovered steam and hot oil lines. Rags used to wipe up spills of benzaldehyde and activated carbon used to absorb vapors of benzaldehyde care must be taken when disposing of these materials (REF). Health Hazards: a) Benzaldehyde: Inhalation of concentrated vapor may irritate eyes, nose and throat. Liquid is irritating to eyes. Prolong contact with skin may cause irritation. Over exposure to benzaldehyde vapors is irritating to upper respiratory tract and produces central nervous system depression with possible respiratory failure. Highly irritant action on mucous membranes carcinogenic effects of benzaldehyde are current in progress. Benzaldehyde is released to the environment in emissions from combustion processes such as gasoline and diesel engines, incinerators and wood burning. It is formed in the atmosphere through photochemical oxidation of toluene and other aromatic hydrocarbons. It occurs naturally in various plants. If released to the atmosphere, benzaldehyde will degrade by reaction with photochemically produced hydroxyl radicals (half-life of 29.8 hr); direct photolysis may contribute to its atmospheric degradation. Physical removal from air by wet deposition can occur. If released to soil or water, the major degradation pathway is expected to be biodegradation. Physical transport from water can occur through volatilization. Occupational exposure to benzaldehyde through consumption of food (where it occurs either naturally or as an intentional food additive) and inhalation of contaminated air. b) Toluene : (7) - Toluene can effect you when breathed in and by passing through your skin. - Toluene may cause mutations genetic changes. Handle with extreme caution. - It may damage the developing fetus (FOETUS). - Exposure can irritate the nose, throat, and eyes. - Higher levels can case you to feel dizzy, light headed and even death can occur. - Repeated exposures can damage bone narrow causing low blood cell count. It also can damage the livers and kidneys. - Long-term exposure can cause tiredness, confusion, weakness, drunken-type actions, memoryloss, nausea and loss of appetite, and hearing loss. It can also cause permanent brain and speech damage, vision problems, loss of music control, and poor balance. It can also cause slowed reflexes, trouble concentrating and decreased metal ability. - Prolonged contact can cause skin rash. - Studies have shown that unborn animals were breathed by their mothers. Babies can have neuralgic problems and retarded growth and development if their mother breathe a high level of Toluene during pregnancy. - The department of health and human services and the international agency for research on cancer have not classified toluene for carcinogenic effect. Studies in workers and animals indicate that toluene does not cause cancer. - Asthmatics, individuals with other respiratory difficulties or cardiovascular disease, and the elderly may be at increased risk from exposure to toluene. Cigarette smokers and chronic alcohol drinkers may also be at increased risk.(8) c) Benzotrichloride : i) Acute effects : - Acute exposure to the vapors of benzotricloride are highly irritating to the skin and mucous membranes. (11,12) - Benzotrichloride may cause death or permanent injury after an acute exposure to small quantities by inhalation. (12) - Large doses have caused CNS depression in animal’s (11). - Tests involving acute exposure of animals, such as the LC50 and LD50 tests in rats and rabbits, have demonstrated benzotrichloride to have extreme acute toxicity by inhalation, moderate. Acute toxicity by dermal exposure, and low to moderate acute toxicity by injestion.(13) - EPA’s office of air quality planning and standards, considers benzotrichloride to be a “high concern” pollutant based on severe acute toxicity. ii) Chronic Effects: - No information is available on the chronic (long-term) effects of benzotrichloride in humans - In mice and rats chronically exposed by inhalation, proliferative lesions of the respiratory tract have been observed. In addition, inflammation of the lymph nodes, liver, spleen, and kidneys have been reported inn mice. - No information is available on the reproductive or developmental effects of benzotrichloride in humans. - Reduced maternal and fetal weight gain and skeletal abnormalities have been reported in rats exposed to benzotrichloride via gavage. - EPA has classified benzotrichloride as a group B2, probable human carcinogen. (12). D) Chlorine :

PLANT LAYOUT One of the first duties of the project Engineer will be to develop the plant layout (including the details equipment arrangement) which serves as a starting point for many of the specialized design functions such as Civil Engg. and piping designer, it will also influence every other design function, including process design. Because of its influence on all other work, the plant layout along with process design: is one of the most important factors in determining the sources of failure of the project.

FUNCTIONS OF PLANT LAYOUT: One of the prime functions of the layout is determine the dimensions of the plot of ground that will be required for the plant or to determine whether the plant can be arranged to fit on our available site. If the development of the layout proceeds simultaneously with the development of the process design is likely to be obtained. Among other things, simultaneous development will help. i) Determine the optimum proportions of various items of equipments. ii) Determine whether gravity flows or pumps are desirable for liquid transport and iii) Achieve maximum utilization of necessary building and structures while avoiding a design that would lead to wastage of structures. The lay-out asset the project engineer in co-ordinating the work of various designers far by allotting space for equipment and facilities so mechanical engineers can do their work simultaneous without interference. For instance by allocating blocks of space for piping runs, the lay out assures the piping designers that they can work in those space. Without visking interference’s with structural members and assures the Civil Engineer that they can place their structural members in other spaces without interfering with piping. The development of layout also permits the orientation (Locating preciously) of those nozzles and vessels and heat exchanges so the designs of these items can be finalized before piping design has advanced very far.

FACTORS TO BE CONSIDERED IN PLANT LAYOUT: During the development of layout and the process designer the project engineer should consider the needs for plant expansion. Shelter is required whenever there is need to protect operator equipment from whether, and very elaborate buildings may be required necessary to maintain a special atmosphere such as in the packing rooms of some pharmaceutical plants. In large size continuous process plants less and fewer shelters are being provided as the equipment becomes larger and more reliable and as the techniques for remote surveillance and control become better developed. It must be remembered that if shelter is provided, it may be necessary to province exceptionally ventilation in order to prevent the accumulation of hazardous vapors etc. Maintenance requirements can be the most important factor in arrangement of equipment for some plants. Some equipment’s such as complex machinery and heat exchanges in severely corrosive a severely fouling services, may require frequent maintenance. At the very last such equipment requires easy access and it may attention should be paid to the major safely instruction in layout of isolation of hazards and escape for operation unless it is impossible for an operator be more a few steps away from an exit, one or more escape should be provided as to reduce to minimum the responsibility of fire or other hazards blocking his escape. In the case of novel process, it must be recognized that deification’s are almost invariable, project Engineer should assure that sufficient space is kept clear to permit increasing a size of equipment or even for adding equipment to the plant. Information required for plant layout: 1) A process flow sheet showing : 2) Every item of major equipment and its size. 3) Materials of construction of equipment and piping if these will introduce special support for other layout problems. 4) Those factors having a significant effect on piping design such as i) Operating pressure and temperature. ii) Flow quantity. iii) The nature of flowing fuel example vapor liquid slurry paste. Etc. 5) Drawing for mechanical equipment showing. a) Vertical dimensions. b) Space required to be left clear for maintenance. c) Location of connection. 6) Hazards of materials handled as they affect requirements for : a) Separation of equipment’s. b) Ventilation. c) The water or other barriers. 7) An area plan that shown neighbouring features that may influence the layout such as : a) Steam, water sewage disposal and other sewage b) Raw material and product storage at pipe lines. c) Sources of atmosphere pollution that may affect the process (preliminary are consuming process) or the operation. 8) Load bearing ability of the soil and subsurface condition. 9) Atmosphere condition with regard to : a) Extremes of weather which may make it desirable to provide shelter, a production for equipment or operation. 10) Prevailing wind direction if there are items such as in take or exhaust stack or furnaces, that should be located up or down wind of the remain of the plant. 11) Preferred operating and maintenance practices as they affect a) Shelter that the operation are accumulated to b) The need for the permanent or temporary shelter when performing maintenance our mechanical equipment’s such as pumps, Compressors, Centrifuges etc. c) The selection between permanently installed holly became and mobile cranes for maintenance. d) The location of locker rooms, Lunch rooms etc at each operating unit or at a central location. 12) Design Standards including the following : a) Minimum permissible clearance between adjacent equipment or between equipment and adjacent structures. b) Maximum permissible straight slopes and minimum rise between landings. c) Preferred tube lengths for shell and tube heat exchanges. d) Placement of over heads conduit either overheads or buried. e) Location of Motor starter near the motor in the operating area or in a remote motor control centre.

PLANT LOCATION: The geographical location of the final plant can have strong influence on the success of an industrial venture. Considerable care must be exercised in selecting the plant site, and many different factors must be considered. Primarily, the plant should be located where the minimum cost of production and distribution can be obtained, but other factors, such as room for expansion and safe living conditions for plant operation as well as the surrounding community, are also important. A general consensus as to the plant location should be obtained before a design project reaches the detailed estimate stage, and a firm location should be established upon completion of the detailed estimate design. The choice of the final site should first be based on a complete survey of the advantages and disadvantages of various geographical areas and, ultimately, on the advantages and disadvantages of available real estate. The following factors should be considered in selecting a plant site: 1. Raw materials availability 2. Markets 3. Energy availability 4. Climate 5. Transportation facilities 6. Water supply 7. Waste disposal 8. Labor supply 9. Taxation and legal restrictions 10. Sire characteristics 11. Flood and fire protection 12. Community factors. The factors that must be evaluated in a plant location study indicate the need for a vast amount of information, both quantitative (statistical) and qualitative. Fortunately, a large number of agencies, public and private, publish useful information of this type greatly reducing the actual original gathering of the data. Raw materials availability: The source of raw materials is one of the most important factors influencing the selection of a plant site. This is particularly true if large volumes of raw materials are consumed, because location near the raw materials source permits considerable reduction in transportation and storage charges. Attention should be given to the purchased price of the raw materials, distance from the source of supply, freight or transportation expenses, availability and reliability of supply, purity of the raw materials, and storage requirements. Markets: The location of markets or intermediate distribution centers affects the cost of product distribution and the time required for shipping. Proximity to the major markets is an important consideration in the selection of a plant site, because the buyer usually finds it advantageous to purchase from nearby sources. It should be noted that products as well as for major final products need for markets. Energy availability: Power and steam requirements are high in most industrial plants, and fuel is ordinarily required to supply these utilities. Consequently, power and fuel can be combined as one major factor in the choice of a plant site. Electrolytic processes require a cheap source of electricity, and plants using electrolytic processes are often located near large hydroelectric installations. If the plant requires large quantities of coal or oil, location near a source of fuel supply may be essential for economic operation. The local cost of power can help determine whether power should be purchased or self generated. Climate: If the plant is located in a cold climate, costs may be increased by the necessity for construction of protective shelters around the process equipment, and special cooling towers or air conditioning equipment may be required if the prevailing temperatures are high. Excessive humidity or extremes of hot or cold weather can have a serious effect on the economic operation of a plant, and these factors should be examined when selecting a plant site. Transportation facilities: Water, railroads, and highways are the common means of transportation used by major industrial concerns. The kind and amount of products and raw materials determine the most suitable type of transportation facilities. In any case, careful attention should be given to local freight rates and existing railroad lines. The proximity to railroad centers and the possibility of canal, river, lake or ocean transport must be considered. Motor trucking facilities are widely used and can serve as a useful supplement to rail and water facilities. If possible, the plant site should have access to all three types of transportation, and, certainly, at least two types should be available. There is usually need for convenient air and rail transportation facilities between the plant and the main company headquarters, and effective transportation facilities for the plant personnel are necessary. Water supply: The process industries use large quantities of water for cooling, washing, steam generation, and as a raw material. The plant, therefore, must be located where a dependable supply of water is available. A large river or lake is preferable, although deep wells or artesian wells may be satisfactory if the amount of water required is not too great. The level of the existing water table can be checked by consulting the state geological survey, and information on the constancy of the water table and the year round capacity of local rivers or lakes should be obtained. If the water supply shows seasonal fluctuations, it may be desirable to construct a reservoir or to drill several standby wells. The temperature, mineral content, site or sand content, bacteriological content, and cost for supply and purification treatment must also be considered when choosing a water supply. Water disposal: In recent years, many legal restrictions have been placed on the methods for disposing of waste materials from the process industries. The site selected for a plant should have adequate capacity and facilities for correct waste disposal. Even though a given area has minimal restrictions on pollution, it should not be assumed that this condition would continue to exit. In choosing a plant site, the permissible tolerance levels for various methods of waste disposal should be considered carefully, and attention should be given to potential requirements for additional waste treatment facilities. Labor supply: The type and supply of labor available in the vicinity of a proposed plant site must be examined. Consideration should be given to prevailing pay scales, restrictions on number of hours worked per week, competing industries that can cause dissatisfaction or high turnover rates among the workers, and variations in the skill and productivity of the workers. Taxation and legal restrictions: State and local tax rates on property income, unemployment insurance, and similar items vary from one location to another. Similarly, local regulations on zoning, building codes, nuisance aspects, and transportation facilities can have a major influence on the final choice of a plant site. In fact, zoning difficulties and obtaining the many required permits can often be much more important in terms of cost and time delays than many of the factors discussed in the preceding sections. Site characteristics: The characteristics of the land at a proposed plant site should be examined carefully. The topography of the tract of land and the soil structure must be considered, since either or both may have a pronounced effect on construction costs. The cost of the land is important, as well as local building costs and living conditions. Future changes may make it desirable or necessary to expand the plant facilities. Therefore, even though no immediate expansion is planned, a new plant should be constructed at a location where additional space is available. Flood and fire protection: Many industrial plants are located along rivers or near large bodies of water, and there are risks of flood or hurricane damage. Before selecting a plant site, the regional history of natural events of this type should be examined and the consequences of such occurrences considered. Protection from losses by fire is another important factor in selecting a plant location. In case of a major fire, assistance form outside fire departments should be available. Fire hazards in the immediate area surrounding the plant site must not be overlooked. Community factors: The character and facilities of a community can have quite an effect on the location of the plant if a certain minimum number of facilities for satisfactory living of plant personnel do not exit, it often becomes a burden for the plant to subsidize such facilities. Cultural facilities of the community are important to sound growth. Churches, libraries, schools, civic theaters, concert associations, and other similar groups, if active and dynamic, do much to make a community progressive. The problem of recreation deserves special consideration. The efficiency, character, and history of both state and local government should be evaluated. The existence of loss taxes is not in itself a favorable situation unless the community is already well developed and relatively free of debt.




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