Chloromethanes namely methyl chloride (CH3Cl), methylene chloride (CH2Cl2), Chloroform (CHCl3) and Carbon Tetrachloride (CCl4) are produced by direct chlorination of Cl2 in a gas phase reaction without any catalyst.

1. Chemical Engineering
Department.
Port Said University.
Petrochemicals Engineering ,
CHE 421
Chloromethanes from
methanol
Presented by:
1. Abdelrahman Ayman El-Bagalaty
2. Hossam El-Din Tarek Tammam
3. Mahmoud Nasser El-Sayed
Dr/Ahmed El-Mohamady

2. Outlines
1.Introduction
2.Reactions
3.Process flow sheet
4.Uses
5.Environmental effects

3. Introduction
 Chloromethane was first synthesized in 1835 by boiling a mixture of methanol, sulfuric acid,
and sodium chloride.
 Chloromethanes namely methyl chloride (CH3Cl), methylene chloride (CH2Cl2), Chloroform
(CHCl3) and Carbon Tetrachloride (CCl4) are produced by direct chlorination of Cl2 in a gas
phase reaction without any catalyst.
Methyl Chloride
CH3Cl
Methylene Chloride
CH2Cl2
Chloroform
CHCl3
Carbon Tetrachloride
CCl4

4. Introduction

5. Reactions
 When a mixture of methane and chlorine is exposed to ultraviolet light a
substitution reaction occurs and the organic product is chloromethane.
 However, the reaction doesn't stop there, and all the hydrogens in the methane can
in turn be replaced by chlorine atoms. That means that you could get any of
chloromethane, dichloromethane, trichloromethane or tetrachloromethane.

6.  You might think that you could control which product you got by the proportions of
methane and chlorine you used, but it isn't as simple as that. If you use enough chlorine
you will eventually get CCl4, but any other proportions will always lead to a mixture of
products
 The reactions are very exothermic
 The feed molar ratio affects the product distribution. When CH4/Cl2 is about 1.8, then
more CH3Cl is produced. On the other hand, when CH4 is chosen as a limiting reactant,
more of CCl4 is produced. Therefore, depending upon the product demand, the feed ratio
is adjusted.

7. Process flow sheet

8. Process flow sheet
 Methane and Cl2 are mixed and sent to a furnace.
 The furnace has a jacket or shell and tube system to accommodate feed pre- heating to desired
furnace inlet temperature (about 280 – 300 o
C).
 To control temperature, N2 is used as a diluent at times.
 Depending on the product distribution desired, the CH4/Cl2 ratio is chosen.
 The product gases enter an integrated heat exchanger that receives separated CH4 (or a mixture of
CH4 + N2) and gets cooled from the furnace exit temperature (about 400 o
C).
 Eventually, the mixture enters an absorber where water is used as an absorbent and water absorbs
the HCl to produce 32 % HCl.
 The trace amounts of HCl in the vapour phase are removed in a neutralizer fed with NaOH.
 The gas eventually is compressed and sent to a partial condenser followed with a phase separator.
The phase separator produces two streams namely a liquid stream consisting of the chlorides and the
unreacted CH4/N2.
 The gaseous product enters a dryer to remove H2O from the vapour stream using 98% H2SO4 as
the absorbent for water from the vapour.
 The chloromethanes enter a distillation sequence.
 The distillation sequence Consists of columns that sequentially separate CH3Cl, CH2Cl2, CHCl3
and CCl4.

9. Uses
 Chloromethane CH3Cl
Chloromethane was once widely used as a refrigerant (chloromethane was called Freon-40),
but it has long since been replaced by substances that are less toxic and less harmful to the
ozone layer in Earth’s atmosphere. Currently, it is used in industry as a reagent in chemical
production, an extractant for oils and resins, a propellant in foam production, and a solvent
in rubber manufacture and petroleum refining.
 Dichloromethane CH2Cl2
• Food technology uses dichloromethane as a solvent.
• In aerosol formulations, it is used as a solvent.
• Pharmaceutical products are manufactured using it as a solvent.
• Dichloromethane is also used to blow foam.
• A degreasing agent, CH2Cl2, is employed.
• Electronics are manufactured with it.

10. Uses
 Trichloromethane CHCl3
It is also used as raw material for producing the hydrochlorofluorocarbon-22 but it will be
phased out in the European Union by 2025. Formerly, it was widely used as an anesthetic,
but due to toxic affects its use is abandoned. As it is anesthetic, so it is also used by the
criminals to knock out their targeted persons or victims. It is used in the pharmaceutical
industry, for the extraction of penicillin and antibiotics, in the manufacturing of dyes, and as
the degreasing agent.
It is used as a chemical intermediate and in the pesticide formulations. it is widely used as a
solvent for alkaloids, fats, iodine, and other substances. In the form of chloroform, it is used
to manufacture the Freon refrigerant R-22. However, in the developing countries, the
application of this refrigerant has been banned due to global warming issues, but in
developing countries, still, its demand is high due to the easy manufacturing and
availability.

11. Uses
 Tetrachloromethane CCl4
Carbon tetrachloride was routinely used to produce chlorofluorocarbons for refrigeration
until the 1980s. Fire extinguishers and cleaning agents were also made with it. A number of
countries have phased out the use of this compound because of the severe health hazards
related to these chemical sand the severe environment damage they cause. These are some
of the niche uses of this compound, which are listed below.
• In a named reaction referred to as the Appel reaction, carbon tetrachloride is used as a
chlorine source.
• Watermarks can also be revealed using this method without affecting the stamp in any
way.
• Lava lamps were also made from carbon tetrachloride.

12. Environmental Effects
 Chloromethane CH3Cl
Chloromethane can affect your brain and nervous system if you breathe in a large amount. It may
cause dizziness, headaches, difficulty speaking, loss of consciousness, or coma.
Exposures to large amounts of chloromethane may also cause liver and kidney problems. It can
also affect your heart rate and blood pressure. Individuals have died after inhaling chloromethane
that leaked from old refrigerators.
Chloromethane can be very irritating if it is left on your skin or if it gets into your eyes.
Studies in animals show that chloromethane exposure may cause reproductive effects like
decreased fertility and poorly formed sperm. It is unknown if developmental effects seen in
animals, such as serious bone problems, would be seen in humans.
Information on whether chloromethane can cause cancer is limited. Some studies have reported
that certain genetic factors may make some people more likely to get cancer if they are exposed
to chloromethane. However, there is not enough information to be sure.

13. Environmental Effects
 Dichloromethane CH2Cl2
There may be an endless list of uses and application of methylene chloride, but its utility cannot
cast a shadow on its toxicity. Although it is one of the least toxic polyhalogenated compounds, its
harmful effect on the human body is not unknown. It affects the central nervous system of the
human body. Even a slight exposure to dichloromethane can cause hearing and vision
impairments. In case of direct contact with human skin, it causes redness of the skin along with
intense burning. Exposure to methylene chloride in high doses leads to numbness in fingers,
dizziness, tingling, and nausea. Continuous exposure to methylene chloride causes irritation in
respiratory tracks, difficulty in concentrating, headache and eye irritation. Studies have shown its
carcinogenic properties, it causes lung, liver, and pancreatic cancer in animals.
Many countries use warnings on products that have dichloromethane in them. Some countries
have banned the use of methylene chloride. Indian industries continue to use methylene
dichloride with certain regulations from the government. Scientists are working hard to develop
alternatives to dichloromethane.

14. Environmental Effects
 Trichloromethane CHCl3
Trichloromethane has adverse effects on the environment and the human body. In terms of the
atmospheric pollutants, it is not considered to cause significant deleterious effects. During the
major accidental spills, it may be hazardous to the water-dwelling organisms. If it is spilled on the
land, it is leached to the groundwater where it can reside for long periods. In the food chain, its
bioconcentration is not known and its little amount is adsorbed to the sediments or soil.
Trichloromethane has negligible photochemical reactivity in the low tropospheric ozone layer. It
does not have any contribution to the photochemical smog. In the atmosphere, it has a long life
ranging for months and through the air, it is transported to long distances.
If the concentration of chloroform is 900 ppm in the air then it causes fatigue, headache, and
dizziness. It has harmful effects on the central nervous system, liver, digestive system, eye, and
kidneys. If chloroform is oxidized in the presence of light, it produces phosgene that is highly
poisonous gas. So, due to this reason, it is stored in the airtight bottles having the dark color to
avoid its contact with the air. Nowadays the applications and uses of trichloromethane are
overshadowed due to harsh effects on the environment.

15. Environmental Effects
 Tetrachloromethane CCl4
Despite the fact that tetrachloromethane has a wide range of applications, its use is highly restricted.
Tetrachloromethane is a greenhouse gas that depletes the ozone layer and contributes significantly to
environmental damage and global warming. It is a volatile organic compound, but because it does not
react, it has no effect on the formation of ground-level ozone. When tetrachloromethane is spilled on
the soil, it quickly evaporates, though some is leached into the groundwater and causes contamination.
Tetrachloromethane, which causes ozone depletion, is extremely stable in the lower atmosphere, with a
residence time of up to 30-50 years. Because of its chemical stability, it can reach the upper
atmosphere, where it is subjected to intense ultraviolet radiation, which causes it to degrade to
chlorine. When this chlorine reacts with ozone, it depletes the ozone layer, which protects life from
harmful ultraviolet radiation. It is a weak greenhouse gas that contributes significantly to global
warming.
Tetrachloromethane does not pose a serious health risk in normal concentrations in the environment. It
can cause severe damage to the liver, kidneys, and central nervous system at high levels. It may also
cause cancer. Exposure to high levels of tetrachloromethane can result in coma or even death. Aquatic
organisms are also poisoned by tetrachloromethane.

16. References
 https://www.mdpi.com/2073-4344/10/12/1462/htm
 https://byjus.com/chemistry/dichloromethane-the-uses-and-effects-on-
environment/
 https://www.w3schools.blog/uses-and-environmental-effects-of-trichloromethane
 https://infinitylearn.com/surge/blog/neet/environment-effects-of-
tetrachloromethane/
 Dryden C. E., Outlines of Chemical Technology, East-West Press, 2008
 Shreve R. N., Austin G. T., Shreve's Chemical process industries, McGraw– Hill, 1984

17. Thank You