Industrial chemistry Flashcards
Factors to be considered in establishing chemical industries
Capital
Labour
Technology
Supply of raw materials
Transportation and market
Site of installation
Mg as a raw material
Extraction of Mg from sea water is more profitable
Other than Na+, Mg2+ is the most abundant cation in sea water
0.13% by weight is Mg in sea water
What process is used for extraction of Mg
Dow process
Major steps of Dow process
- Thermal decomposition of limestone or Dolomite to obtain CaO (using limestone is advantageous)
- Precipitation of Mg(OH)2
- Mg(OH)2 formed is filterd and removed and reacted with concentrated HCl to get MgCl2.
- The solution is heated strongly to vaporize water.
- solid formed is fused in the steel chambers where electrolysis is done and then it is electrolized
Temperature maintained in the dow process
700-800 C
Melting point of Mg
650 C
Uses of Mg
Production of aircrafts and vehicles
Production of alloys
Percentage yield of Mg in dow’s process
99.8
Caustic soda
NaOH
Basic process of caustic soda production
A pure concentrated solution of sodium chloride is called brine. NaOH is produced by electrolyzing a brine solution. As the by-products hydrogen gas and chloride gas are released at the cathode and the anode respectively.
Types of cells used to produce caustic soda and their common name
Chlor-alkali cells
a) Mercury cells
b) Diaphragm cells
c) Membrane cells
Major steps in membrane cell method
- Removal of contaminants (SO4 2-, Mg2+, Ca2+) from brine solution
- Electrolysis in Ti anode producing Cl2 and Na+
- Electrolysis of water in Ni cathode producing H2 and OH-
- Transportation of Na+ from anode to cathode through pores of the membrane.
- Evaporation of NaOH
Uses of NaOH
- Production of soap
- Production of paper, artificial silk and dyes
- Using as a strong base
- Precipitation of heavy metal as their hydroxides in waste water treatment.
Uses of Cl2
- Bleaching textiles, woods and paper pulp
- Purifying the drinking water
- Production of HC1
- Production of chlorinated rubber, insecticides, dyes and medicine
- Production of vinyl chloride required to produce polymers like PVC
Uses of H2
- Manufacture of HCl
- Production of NH3
- Production of margarine by hydrogenation of vegetable oil
- Using as a fuel
Basic process of making soap and raw materials
Raw materials are animal fat or plant oil, NaOH or KOH
triglycerides are subject to a hydrolysis reaction with caustic soda (saponification) forming glycerol and sodium salts of long chain carboxylic acids.
Processes of soap manufacturing and their major steps
Hot process and the cold process
In the cold process, soap and glycerol are not separated
Steps of hot process
1. Saponification
2. Removal of the by-product, glycerin
3. Purification
4. Finishing
Caustic potash
KOH
Saponification
Purified vegetable oil is mixed with NaOH or KOH. Glycerin are soap (RCOONa) are produced
System is maintained at 70 C
Removal of glycerin
To decrease the solubility of soap in the aqueous phase NaCl (brine) is added. Glycerin dissolves in the salt solution.
Purification
Wet soap with salt is centrifuged
NaCl content in soap decreases to 0.5% (w/w)
Citric acid, phosphoric acid or free fatty acids associated with coconut oil are added to neutralize sodium hydroxide
Finishing
Soap heated to about 120 C is sprayed into a low pressure zone in the form of small droplets. Finally fillers, colours and perfumes are added
TFM value of soap
TFM (Total Fatty Matter) means the total fatty matter presents in soap. It is the percentage of RCOONa (soap) present in a cake of soap.
TFM value of a cake of washing soap
54-56% and the rest is fillers
Detergents
do not precipitate in hard water. The main ingredients of artificial detergents is sodium alkylbenzenesulphonate.
Process used in the production of Na2CO3
Solvey process
Raw materials of Solvey process
NH3 obtained through Haber process
CO2 obtained by the thermal decomposition of limestone
Brine solution
Steps of Solvey Process
Ammonification
Carbonation
Separation of NaHCO3
Obtaining Na2CO3 by heating NaHCO3
Countercurrent principle
Mixing reactants efficiently by sending the reactants in opposite directions is referred to as the countercurrent principle.
Ammonification
First the brine solution is introduced from the top of the tower and ammonia gas is introduced from the bottom of the tower.Ammonification of brine is an exothermic process. It is important to maintain a low temperature.
Carbonation
The brine solution saturated with ammonia is introduced from the top of the second tower while CO2 is introduced from the bottom. Reaction is exothermic and the tower is kept cool.
Regeneration of NH3 in solvey process
NH4Cl which is a by-product is used to generate NH3. NH4Cl is reacted with CaO obtained by the decomposition of CaCO3
Final by product of the Solvey process
CaCl2
Uses of Na2CO3
1) Removal of hardness of water
2) Addition to improve cleaning action when producing soap and detergents.
3) Using as washing soda
4) Mixing to the wood pulp in paper industry
5) Production of glass
Raw materials used in Haber-Bosch process
N2 gas and H2 gas are the main raw materials. N2 gas is separated by fractional distillation of liquefied atmospheric air. Therefore N2 gas has a production cost.
Hydrogen gas is obtained by cracking hydrocarbons
Percentage of NH3 used for fertilisers
83%
more than 80% to produce urea
The optimum industrial conditions employed for the Haber-Bosch process
temperature in the range 450-500 C,
a pressure of 250-300 atm,
iron catalyst and
K2O and Al2O3 as catalystic promoters.
Uses of NH3
- Production of nitric acid, fertilizers and nylon
- Petroleum industry utilizes ammonia in neutralizing the acid constituents of crude oil
- Used in water and waste water treatment, such as pH control
- Used as a refrigerant
- Used in the rubber industry for the stabilization of natural and synthetic latex to prevent premature coagulation
Raw materials of Ostwald method
ammonia gas, atmospheric air and water
The optimum industrial conditions employed for the Ostwald process
Temperature 800-850
Pt/Rh catalyst
Uses of nitric acid
- Making fertilizer and explosives
- Making nitrates essential for industries KNO3 – to produce gun power
AgNO3 – photography - Making aqua regia
- Cleaning surfaces when welding metals
H2S2O7
Pyrosulfuric acid / oleum
Why H2SO4 cannot be produced directly by adding water to SO3
Reaction between SO3 and H2O is highly exothermic and violent hence only a mist of H2SO4 will be produced.
The optimum industrial conditions employed for the contact process
1 atm
400-500
V2O5 catalyst
Basic steps of contact process
Liquid sulfur heated upto 140 and atmospheric air is supplied to the furnace
Formed SO2 is transferred to the reaction chamber with V2O5 catalyst surfaces
Conc.H2SO4 is sprayed onto SO3 forming oleum
Uses of H2SO4
- Production of phosphate fertilizers
- Production of ammonium sulphate fertilizer
- Production of artificial fibers including rayon and plastics
- Production of detergents containing alkyl and aryl sulphonates 5. Production of dyes, explosives and medicines
- Production of battery acid
- Drying gases
Main minerals containing Ti
Ilmenite (FeOTiO2) and rutile (TiO2)
Sulfate process
Removal of FeO from ilmenite is called sulphate process.
Production process of TiO2 and its main steps
Chloride process
1.Chlorination
2.Oxidation
Overall reaction of the chlorination process and the temperature maintained
Before this process rutile and coke are dried by heating to 200-300
TiO2 + C + Cl2 —–> TiCl4(g) + CO2(g)
950
Overall reaction of the oxidation process and the temperature maintained
TiCl4 (g) + O2(g) —–> TiO2 (s) + 2Cl2 (g)
1000
Uses of TiO2
- TiO2 is white in colour. Therefore it is used as a pigment to obtain bright white colour in paint, plastic goods and paper. The high refractive index if TiO2 is also a reason for using it as a pigment.
- TiO2 is chemically inert. Therefore it is used as a pigment to give white colour to medicine and toothpaste.
- TiO2 is also used to produce substances applied to prevent sunburns in the skin due to UV radiations in solar rays. TiO2 prevents the reach of UV rays to the skin.
- It is used to make some solar cells.
Raw materials essential for iron extraction
- Iron ore
- Limestone
- Coke (coal)
- Air
Slag
Calcium silicate (CaSiO3) and calcium aluminate (Ca(AlO2)2) formed are called the slag. The density of the slag is lower than that of molten iron. Therefore liquid slag layer floats on molten iron. As the slag covers the surface of molten iron, the chances for molten iron to react with oxygen are less.
Production of vinegar
Acetic acid is the active ingredient. Toddy is subject to continued microbial activity it is oxidized to acetic acid. Artificial vinegar is produced by diluting appropriately, the acetic acid obtained by the oxidation of ethanol produced from raw materials turned out by petroleum industry.
Uses of ethanol
Solvent for perfumes and scents
Environmental-friendly renewable fuel source
Highest ethanol percentage
96.5%
rectified spirit
Fraction distillation
The distillation technique used to separate components which are miscible and have different boiling points from a mixture
Methods of extracting essential oils
Steam distillation
Solvent extraction
Pressing
Pressing method is rarely used because
- The yield is poor
- Oil gets mixed up with other organic substances
Raw materials of biodiesel production
Non-volatile plant oils (triglycerides)
Methanol
NaOH is used as a catalyst
Steps used in biodiesel production
- Free fatty acids and non-saponifiable compounds in the plant oils are removed
- NaOH catalyst is dissolved in methanol and the mixture is mixed with triglycerides
- Transesterification reaction produces biodiesel and glycerol
- Glycerol layer is separated
- By separating and heating the layers, methanol contained in them can be removed.
Iron ore contains
Hematite Fe2O3
Magnetite Fe3O4
Main components of cinnamon oil
Leaf – eugenol
Bark – cinnamaldehyde
Root – camphor
Main constitution of citronella oil – geraniol