3. Basic Organic Products Outline Introduction to Industrial organic synthesis Manufacture of Methanol and Isopropanol Manufacture of Formaldehyde and Acetaldehyde Manufacture of Acetic acid Manufacture of Acetone Manufacture of Phenol and Styrene

3.1. Introduction to Industrial organic synthesis The products of industrial organic synthesis are varied in their chemical nature: They are synthetic hydrocarbons oxygen-containing compounds Halogen-containing & sulfur-containing cpds,& nitriles products of industrial organic synthesis are used as intermediates in various chemical industry(production of synthetic rubbers , fibers, plastics, dyes & biologically active compounds) The raw materials for industrial organic synthesis are Alkanes & unsaturated hydrocarbons Aromatic hydrocarbons various inorganic compounds

3.2 Manufacture of Methanol and Isopropanol Methyl alcohol (methanol, wood alcohol, CH3OH; boiling point: 64.7oC,density: 0.7866) is a colorless, mobile liquid with a mild characteristic odor. Methanol is the raw material for many chemicals, formaldehyde, dimethyl terephthalate , methylamines and methyl halides, methyl methacrylate, acetic acid, gasoline etc. Traditionally methanol was made from destructive distillation of wood ,so it is known as wood alcohol Now methanol is produced by synthetic methods from Mixture of carbon monoxide (CO) and hydrogen gas (H2) Methanol synthesis The main process area of the plant can be divided into three sections Reforming Compression and Synthesis Distillation

CH4 + H2O CO + 3H2 ΔrH = +206 kJ mol-1 CO + H2O CO2 + H2 Reforming Refers to the endothermic reaction between steam and methane (or any other alkane) which produces CO, CO2& H2. The reaction is carried out in a furnace at high temperatures over a nickel catalyst Reaction: CH4 + H2O CO + 3H2 ΔrH = +206 kJ mol-1 CO + H2O CO2 + H2 Compression and Synthesis The "synthesis gas" from the reformer is then compressed In a centrifugal compressor The compressed synthesis gas enters the converter reactor containing copper zinc and catalyst and the synthesis reaction occurs.

2H2 + CO CH3OH ΔrH = -92 kJ mol-1 As carbon monoxide is used up in the methanol synthesis reaction the water gas shift reaction reverses producing more carbon monoxide: H2 + CO2 CO + H2O ΔrH = +41 kJ mol-1 The overall reactions by which methanol is produced from synthesis gas can be summarised into the following equation: Cu-Zn CO2 + CO + 5H2 → 2CH3OH + H2O + heat During methanol synthesis some side reactions occur which produce higher alcohols (ethanol, propanol, butanol) nCO + 2(n-½)H2 → CnH2nOH + (n-1)H2O nCO + CH3OH + 2nH2 → CnH2n+3OH + nH2O .

Produced crude methanol contains a large range of impurities which have to be removed to produce methanol of chemical grade quality. The technique used for purification is distillation Distillation The distillation system consists of an extraction column, a refining column, and a recovery column. Extraction column: removal of the volatile impurities and dissolved gases – Like CO2, CO, H2, N2, acetone, ethers, esters and volatile Alkanes at low temperature to prevent CH3OH evaporation Refining column: The bottom of the extraction column provides the feed for the Refining column. The feed is vapourised & Methanol leaves at the top of the column with a purity of 99.99%. Recovery column: Feeds from the refining column will be separate methanol from ethanol High purity methanol leaves the top of the column, combines with the refining column product, and is pumped to the storage tanks

Flow chart for manufacturing of methanol

Methanol is used as a major solvent for paints and varnishes. Uses of methanol Methanol is mixed with ethanol and sold in the market as spirit. To make some of the alcohol unsuitable for drinking, about 5% methanol is added, as methanol is poisonous. This type of spirit is called denatured spirit. Denatured spirit is used in spirit lamps, for disinfectant effects, in wood polish, etc. Methanol is used as a major solvent for paints and varnishes. Methanol is used for making dyes, perfumes and synthetic fibbers. Methanol is used for making formaldehyde. Formaldehyde in turn is used for making a type of special insulator called Bakelite. Methanol is used as a replacement for petrol for environmentally friendly cars and buses.  

Iso-propyl alcohol (2-propanol, iso-propanol, rubbing alcohol Introduction Iso-propyl alcohol (2-propanol, iso-propanol, rubbing alcohol is soluble in all organic solvent , colourless liquid , Bpt 82.50C, Mpt-890C It is used in pharmaceutical industry Plantation industry –pesticides, cosmetics –baby oils, lotions, Aerosol –hair spray, detergents, etc. removing sticky residue It is manufactured commonly by the esterification/hydrolysis of propylene indirectly

Synthesis of isopropyl alcohol Direct hydration Propene & water, either in gas or liquid phases, at high pressures in the presence of solid or supported acidic catalysts ,But it is more difficult method The indirect process : Propene with sulfuric acid to form a mixture of sulfate esters and subsequent hydrolysis will produce isopropyl alcohol. It is the most common method The esterification step occurs with 85% sulfuric acid at 24 to 27oC, & dilution to 20% concentration is done in a separate tank. Reaction: CH3CH=CH2 + H2SO4 → CH3CH(OSO3H)CH3 CH3CH(OSO3H)CH3 +H2O → CH3CH(OH)CH3 + H2SO4

Flow chart for manufacturing of isopropyl alcohol Sulphuric acids Propylene gas Rxn of sulphuric acid with propylene Mixer chamber- water feed IPA generation Feed Unabsorbed propylene gas- recycled Acid reconcentration -recycled Distillation column -Ether column -Drying column Output -Diisopropyl ether -isopropyl alcohol and anhydrous

3.3. Manufacture of Formaldehyde and Acetaldehyde Manufacture of formaldehyde from methanol 1.1. Introduction Formaldehyde (methanal, melting point: –92oC, boiling point: –21oC) It is produced solely from methanol by using a silver or a metal oxide catalyst It is building block for many organic compounds, photographing washing, glues, adhesives, paints, explosives, disinfecting agents, tissue preservation and drug testing, etc. 1.2. Manufacturing process It is produced through a catalytic vapor-phase oxidation reaction of methanol with oxygen. Reaction: 2CH3OH + O2 → 2HCH=O + 2H2O ……….1 CH3OH → HCH=O + H2………………………..2

Formaldehyde production using sliver catalyst The silver catalyzed reactions are operated at atmospheric pressure and very high temperatures (600oC – 650oC) . The standard enthalpies of the above two reactions(1&2) are ΔH1 = -156 KJ and ΔH2 = 85 KJ respectively. The first exothermic reaction produces around 50 % -- 60 % of the total formed formaldehyde. The rest is formed by the second endothermic reaction. These reactions are usually accompanied by some undesired byproducts such as Carbon Monoxide (CO), Carbon Dioxide (CO2), Methyl Formate (C2H4O2) and Formic Acid (CH2O2).

Flow chart for formaldehyde manufacture using a silver catalyst

Formaldehyde production using Metal Oxide catalyst Unlike the silver based catalyst formaldehyde formation , the iron-molybdenum oxide catalyst makes formaldehyde from the exothermic reaction (1) entirely. Under atmospheric pressure and 300 – 400 oC, methanol conversion inside the reactor could reach 99% and a yield of 88% - 92%. The process begins by mixing of vaporized methanol and air prior to entering the reactors. An almost methanol-free product can be achieved on this process design. The advantage of this process over the silver based catalyst is the absence of the distillation column to separate unreacted methanol and formaldehyde product

Flow chart for formaldehyde manufacture using a Metal Oxide catalyst

2. Manufacture of Acetaldehyde 2.1.Introduction Acetaldehyde (ethanal, CH3CH=O, melting point –123.5°C, boiling point:20.1°C ) It is a colorless, It has a pungent, suffocating odor that is somewhat fruity & quite pleasant in dilute concentrations. It is miscible in all proportions with water and most common organic solvents It is widely used as a commencing material in organic syntheses, including the production of resins, dyestuffs, & explosives 2.2. manufacturing process The oxidation of ethylene to acetaldehyde by oxygen in water in the presence of tetrachloropalladate(II) as the catalyst , the process is called Wacker process

The main reactions that take place are: C2H5OH + ½ O2 → CH3CHO + H2O C2H5OH → CH3CHO + H2 Two routes are commercialized for the production of acetaldehyde: one-stage & two-stage process . One-stage process Ethylene and oxygen are passed co-currently in a reaction tower at about 130 °C and 400 kPa.[ The catalyst, an aqueous solution of PdCl2 and CuCl2. The acetaldehyde is purified by extractive distillation followed by fractional distillation. Extractive distillation with water removes the lights ends having lower boiling points than acetaldehyde (chloromethane, chloroethane, and carbon dioxide) at the top while water & higher-boiling byproducts, such as acetic acid, &chlorinated acetaldehydes, are withdrawn together with acetaldehyde at the bottom.

A flow chart of acetaldehyde manufacture for the one-stag process

Two-stage process In two-stage process, reaction and oxidation are carried out separately in tubular reactors. Unlike one-stage process, air can be used instead of oxygen. Ethylene is passed through the reactor along with catalyst at 105–110 °C and 900–1000 kPa. Catalyst solution containing acetaldehyde is separated by flash distillation. The catalyst is oxidized in the oxidation reactor at 1000 kPa using air as oxidizing medium. Oxidized catalyst solution is separated and sent back to reactor. Acetaldehyde – water vapor mixture is preconcentrated to 60–90% acetaldehyde by utilizing the heat of reaction & the discharged water is returned to the flash tower to maintain catalyst concentration.

A two-stage distillation of the crude acetaldehyde follows A two-stage distillation of the crude acetaldehyde follows. In the first step, low-boiling substances, such as chloromethane, chloroethane and carbon dioxide, are separated. In the second step, water and higher-boiling by-products, such as chlorinated acetaldehydes and acetic acid, are removed and acetaldehyde is obtained in pure form overhead. In both one- and two-stage processes the acetaldehyde yield is about 95 %. Both methods yield chlorinated hydrocarbons, chlorinated acetaldehydes, and acetic acid as byproducts. the choice of method is governed by the raw material and energy situations as well as by the availability of oxygen at a reasonable price.

A flow chart of acetaldehyde manufacture for the two-stag process

3.4. Manufacture of Acetic acid Introduction Acetic acid (ethanolic acid, vinegar acid, CH3CO2H, melting point 16.6oC,boiling point: 117.9oC) is a colorless, pungent liquid that is miscible with water, alcohol Acetic acid is the active ingredient in vinegar, ranges from 4 to 5% acetic acid. Acetic acid is used for the manufacture of methyl acetate, acetic anhydride ,vinyl acetate, ethyl acetate, terephthalic acid, cellulose acetate, and a variety of acetic esters. 2.Manufacturing process It is manufactured by processes of: methanol carbonylation, acetaldehyde oxidation, and n-butane oxidation Methanol carbonylation In this process, methanol and carbon monoxide react to produce acetic acid according to the equation: CH3OH + CO → CH3COOH

. The process involves iodomethane as an intermediate, and occurs in three steps and it is catalysed by rhodium or Iridium CH3OH + HI → CH3I + H2O 2. CH3I + CO → CH3COI CH3COI + H2O → CH3COOH + HI The yield of acetic acid is 99 percent based on methanol and 90 percent based on carbon monoxide.

Flow chart for Acetic acid manufacture by CH3OH carbonylation

2. Acetic acid from Acetaldehyde oxidation The single-stage (Wacker)process for making acetaldehyde involves cupric chloride and a small amount of palladium chloride in aqueous solution as a catalyst. CH2=CH2 + H2O + PdCl2 → CH3CHO + 2HCl + Pd0 The yield is 95 percent and further oxidation of the acetaldehyde produces acetic acid. 2CH3CHO + O2 → 2CH3CO2H 3. Acetic acid from n-butane oxidation By controlling the condition large percentage of acetic acid can be formed from C4 petroleum. Cobalt, manganese, or chromium acetates are catalysts with temperatures of 50 to –250oC and a pressure of 800 psi 2C4H10 +4 O2 → 2CH3CO2H + HCO2H + CH3CH2OH + CH3OH

3.5. Manufacture of Acetone 1. Introduction Acetone (dimethyl ketone, 2-propanone, CH3COCH3, melting point:–94.6oC, boiling point: 56.30C) is the simplest ketone and is a colorless liquid that is miscible in all proportions with water, alcohol, or ether. Acetone is a very important solvent and is widely used in the manufacture of plastics and lacquers. It is used as a solvent for acetylene, cellulose acetate ,nitrocellulose, as well as for various resins and gums, and as a thinner for lacquers and inking materials . It is the starting ingredient or intermediate for numerous organic syntheses. It is used for the production of methyl methacrylate, solvents, bisphenol A, aldol chemicals, and pharmaceuticals

2. Production process There are different major processes for the production of acetone (2-propanone) 1. Acetone from isopropyl alcohol. Iso-propyl alcohol can be by either dehydrogenation(preferred) or air oxidation. The acetone is purified by distillation. CH3CH(OH)CH3 → CH3C(=O)CH3 + H2 2CH3CH(OH)CH3 + O2 → CH3C(=O)CH3 + 2H2O 2. Acetone from Cumene. In this process, Cumene first is oxidized to cumene hydroperoxide followed by the decomposition of the cumene hydroperoxide into acetone and phenol. The hydroperoxide is made by reaction of cumene with oxygen at 110 to 115oC until 20 to 25 percent of the hydroperoxide is formed

Flow chart of acetone from cumene

Cumene Unit Solid phosphoric acid (SPA) catalyst to promote the alkylation of benzene with propylene to yield high purity Cumene (isopropyl benzene). Oxidation Section oxidation of Cumene to Cumene hydroperoxide (CHP) in the oxidizers. Oxygen is from air and the reaction is carried out in an alkaline environment. The oxidation is a highly exothermic reaction. Cleavage Section Under controlled condition of temperature and acidity, CHP is cleaved to phenol and acetone and byproducts.

3.6. Acetone from distillation of various acetates Acetone is prepared by passing the vapors of acetic acid over heated lime. Calcium acetate is produced in the first step followed by a breakdown of the acetate into acetone and calcium carbonate: CH3CO2H + CaO → (CH3CO2)2Ca + H2O (CH3CO2)2Ca → CH3COCH3 + CaCO3

3.6. Manufacture of Phenol and Styrene 1.introduction Phenol (hydroxy benzene; freezing point: 40.9oC, boiling point: 181.8oC,) at room temperature is a white, crystalline mass. Phenol gradually turns pink if it contains impurities or is exposed to heat / light. It has a distinctive sweet, tarry odor, and burning taste. Phenol has limited solubility in water between 0 and 65oC. Above65.3oC, phenol and water are miscible in all proportions. Phenol is very soluble in alcohol, benzene, chloroform, ether, and partially disassociated organics in general, but it is less soluble in paraffinic hydrocarbons.

2. Manufacturing process Phenol from cumene The peroxidation of cumene (iso-propyl benzene) at 130oC in the presence of air and catalyst followed by decomposition of the peroxide at 55 to 65oC in the presence of sulfuric acid C6H5CH(CH3)2 + O2 → C6H5C(CH3)2OOH C6H5C(CH3)2OOH → C6H5OH + CH3COCH3 By-products of these reactions are acetophenone and dimethyl benzyl alcohol Phenol from toluene Toluene-benzoic acid process involves three chemical reactions: oxidation of toluene to form benzoic acid 2. oxidation of benzoic acid to form phenyl benzoate

3. Hydrolysis of phenyl benzoate to form phenol. 2C6H5CH3 + 3O2 → 2C6H5CO2H + 2H2O 4C6H5CO2H + O2 → 2C6H5CO2C6H5 + 2H2O + 2CO2 C6H5CO2C6H5 + 2OH- → 2C6H5OH + CO2 I n the first step the oxidation of toluene to benzoic acid is achieved with air and cobalt salt catalyst at a temperature between 121 and 177oC. The reactor effluent is distilled, and the purified benzoic acid is collected In the second processing step , the benzoic acid is oxidized to phenyl benzoate in the presence of air and a catalyst mixture of copper and magnesium salts. The phenyl benzoate is then hydrolyzed with steam in the second reactor to yield phenol and carbon dioxide (200oC and atmospheric pressure).

Flow chart phenol from toluene

Manufacture of Styrene Styrene (phenyl ethylene, vinyl benzene; freezing point: –30.6oC, boiling point: 145oC) uses of styrene are dominated by polymer chemistry and involve polystyrene Manufacturing process From the dehydrogenation of ethyl benzene at high T (630oC) with various metal oxides as catalysts, including zinc, chromium, iron, or magnesium oxides coated on activated carbon, alumina etc. C6H5CH2CH3 → C6H5CH=CH2 + H2 Conditions must be controlled to avoid polymerization of the styrene. sulfur can be added to prevent polymerization. The crude product is a mixture of styrene, and ethylbenzene that is separated by vacuum distillation, after which the ethylbenzene is recycled Usually a styrene plant is combined with an ethylbenzene plant when designed.

Flow chart Of Styrene from ethyl benzene