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GB1560893A - Method for drying water-wet methyl chloride - Google Patents

Method for drying water-wet methyl chloride Download PDF

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Publication number
GB1560893A
GB1560893A GB517779A GB517779A GB1560893A GB 1560893 A GB1560893 A GB 1560893A GB 517779 A GB517779 A GB 517779A GB 517779 A GB517779 A GB 517779A GB 1560893 A GB1560893 A GB 1560893A
Authority
GB
United Kingdom
Prior art keywords
water
methyl chloride
chloride
wet
psig
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB517779A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dow Chemical Co
Original Assignee
Dow Chemical Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US05/486,541 external-priority patent/US3981938A/en
Priority claimed from US05/486,539 external-priority patent/US4145260A/en
Application filed by Dow Chemical Co filed Critical Dow Chemical Co
Publication of GB1560893A publication Critical patent/GB1560893A/en
Expired legal-status Critical Current

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Classifications

    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C19/00Acyclic saturated compounds containing halogen atoms
    • C07C19/01Acyclic saturated compounds containing halogen atoms containing chlorine
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C17/00Preparation of halogenated hydrocarbons
    • C07C17/093Preparation of halogenated hydrocarbons by replacement by halogens
    • C07C17/16Preparation of halogenated hydrocarbons by replacement by halogens of hydroxyl groups
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C17/00Preparation of halogenated hydrocarbons
    • C07C17/38Separation; Purification; Stabilisation; Use of additives

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)

Description

(54) METHOD FOR DRYING WATER-WET METHYL CHLQRIDE (71) We, THE DOW CHEMICAL COMPANY, a Corporation organised and existing under the laws of the State of Delaware, United States of America, of Midland, County of Midland, State of Michigan, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement.
The present invention relates to a method of drying water-wet methyl chloride.
In our co-pending Application No.
37339/76 (Serial No. 1560892) we have described and claimed a method for producing a dry C,4 alkyl halide, which method comprises reacting a C, 4 alkanol with at least 10% in excess of the stoichiometric amount of hydrogen halide at a temperature of 50 to 1800C under a pressure of 25 to 400 psig. to maintain a major portion of the water of reaction in the liquid phase; withdrawing a vapour phase containing alkyl halide and hydrogen halide from the reaction zone, and contacting the same with alkyl halide-hydrogen halide liquid reflux; and withdrawing substantially water-free vapour from the contacting zone.
We have now found that methyl chloride prepared by the process described above and water-wet methyl chloride prepared by any other process may be substantially dried by a method which comprises distilling the water-wet methyl chloride in the presence of at least 10 molar 2O hydrogen chloride based on the total weight of acid, water and methyl chloride under a superatmospheric pressure and a temperature of from 100"C to the azeotrope boiling point under the pressure of said distillation, thereby to produce a bottoms from said distillation of not more than 36van by weight aqueous hydrochloric acid and an overhead of methyl chloride and hydrogen chloride containing less than 400 molar ppm. water.
Increasing pressures allow increasing temperatures in the bottoms which form azeotropes of lower concentration hydrochloric acid.
The variables which may be adjusted to provide a lower water content of the methyl chloride and/or a higher or lower acid concentration are the molar percent hydrogen chloride, the reflux ratio, the number of trays (theoretical), the pressure and/or temperature.
This drying process is useful to dry methyl chloride whether the water results from a physical contacting or chemical reaction resulting in the co-mingling of the methyl chloride with water. For example, methyl chloride produced by the hydrochlorination of methanol is as readily dried as methyl chloride physically mixed with water as a result of a treatment of a material in the presence of water and methyl chloride.
The drying process is preferably carried out under superatmospheric pressure from 100 psig. to 300 psig. (7.5-22.5 kg./cm2).
Those temperatures at which the azeotrope of aqueous hydrochloric acid boils at such a pressure are preferable, although lower temperatures are useful if a high acid concentration is desired. Reflux ratios of between 1.3 and 4.0 are desirable to obtain efficient use of the hydrogen chloride.
Conveniently, the theoretical number of plates in the rectifier or column can vary from 10 to 150.
The introduction of hydrogen chloride into the system to obtain the desired distillation conditions is generally made at the still but may be present in the feed as a result of employing as excess over stoichiometric proportions in a reaction, for example in which methyl chloride is produced, or present as a byproduct of a process.
The present invention will be further illustrated by the following Example.
EXAMPLE Methanol (2.903 Ib.-mole) (1.32 kg.-mole) was reacted with 39.7% molar excess above stoichiometric of hydrogen chloride at 166"C. The resulting effluent, methyl chloride, water and unreacted hydrogen chloride, was fed to a 5 1/2 inch I.D. (14.0 cm.)x50ft.(15.3 m.) high distillation column packed with 1/2 inch (1.27 cm.) saddles. The still was operated at 250 psig. (17.7 kg./cm2), 210"C. reboiler with a reflux condenser at 64"C. The molar reflux was set at 2.04. The gaseous product was analyzed for water and found to contain less than 200 ppm. water.
The still bottoms was 9.95 /O by weight aqueous hydrochloric acid.
WHAT WE CLAIM IS: 1. A method for drying water-wet methyl chloride, which method comprises distilling the water-wet methyl chloride in the presence of at least 10 molar% hydrogen chloride based on the total weight of acid, water and methyl chloride under a superatmospheric pressure and a temperature of from 100"C to the azeotrope boiling point under the pressure of said distillation, thereby to produce a bottoms from said distillation of not more than 36van by weight aqueous hydrochloric acid and an overhead of methyl chloride and hydrogen chloride containing less than 400 molar ppm. water.
2. A method as claimed in claim 1, wherein the reflux ratio is from 1.3 to 4.
3. A method as claimed in claim 1 or claim 2, wherein the pressure is from 100 psig. to 300 psig.
4. A method as claimed in any one of the preceding claims, wherein the water-wet methyl chloride has been prepared bv a process as claimed in claim 1 of U.K.
Patent Application No. 37339/76 (Serial No.
5. A method as claimed in claim 1 for drying water-wet methyl chloride substantially as hereinbefore described in the Example.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. chloride, water and unreacted hydrogen chloride, was fed to a 5 1/2 inch I.D. (14.0 cm.)x50ft.(15.3 m.) high distillation column packed with 1/2 inch (1.27 cm.) saddles. The still was operated at 250 psig. (17.7 kg./cm2), 210"C. reboiler with a reflux condenser at 64"C. The molar reflux was set at 2.04. The gaseous product was analyzed for water and found to contain less than 200 ppm. water. The still bottoms was 9.95 /O by weight aqueous hydrochloric acid. WHAT WE CLAIM IS:
1. A method for drying water-wet methyl chloride, which method comprises distilling the water-wet methyl chloride in the presence of at least 10 molar% hydrogen chloride based on the total weight of acid, water and methyl chloride under a superatmospheric pressure and a temperature of from 100"C to the azeotrope boiling point under the pressure of said distillation, thereby to produce a bottoms from said distillation of not more than 36van by weight aqueous hydrochloric acid and an overhead of methyl chloride and hydrogen chloride containing less than 400 molar ppm. water.
2. A method as claimed in claim 1, wherein the reflux ratio is from 1.3 to 4.
3. A method as claimed in claim 1 or claim 2, wherein the pressure is from 100 psig. to 300 psig.
4. A method as claimed in any one of the preceding claims, wherein the water-wet methyl chloride has been prepared bv a process as claimed in claim 1 of U.K.
Patent Application No. 37339/76 (Serial No.
5. A method as claimed in claim 1 for drying water-wet methyl chloride substantially as hereinbefore described in the Example.
GB517779A 1974-07-08 1976-12-09 Method for drying water-wet methyl chloride Expired GB1560893A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US05/486,541 US3981938A (en) 1974-07-08 1974-07-08 Method for producing dry alkyl halides
US05/486,539 US4145260A (en) 1974-07-08 1974-07-08 Process for drying water-wet methyl chloride

Publications (1)

Publication Number Publication Date
GB1560893A true GB1560893A (en) 1980-02-13

Family

ID=27048725

Family Applications (1)

Application Number Title Priority Date Filing Date
GB517779A Expired GB1560893A (en) 1974-07-08 1976-12-09 Method for drying water-wet methyl chloride

Country Status (2)

Country Link
DE (2) DE2640852C2 (en)
GB (1) GB1560893A (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3912094A1 (en) * 1989-04-13 1990-10-25 Rwe Dea Ag METHOD FOR OBTAINING C (DOWN ARROW) 3 (DOWN ARROW) TO C (DOWN ARROW) 4 (DOWN ARROW) MONOALKYL CHLORIDES

Also Published As

Publication number Publication date
DE2640852C2 (en) 1983-08-04
DE2640852A1 (en) 1978-03-16
DE2660740C2 (en) 1984-03-01

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PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee