Indian Patents. 271029:"A PROCESS FOR THE PREPARATION OF 1-BROMOOCTADECANE (STEARYL BROMIDE)"

Title of Invention	"A PROCESS FOR THE PREPARATION OF 1-BROMOOCTADECANE (STEARYL BROMIDE)"
Abstract	A process for the preparation of 1-bromooctadecane comprising the steps of: reacting 1 -octadecanol with hydrobromic acid in the presence of concentrated sulphuric acid to obtain crude 1-bromooctadecane, washing the crude product with 3-6% wash liquid and water. Purifying said crude product by vacuum distillation to obtain atleast 95% of 1-bromooctadecane.

Full Text	FIELD OF INVENTION This invention relates to a process for the preparation of 1-bromooctadecane from indigenously available stearyl alcohol. BACKGROUND OF INVENTION Stearyl bromide is used as an important raw material for the preparation of surfactant, UV absorbing agent, and photographic chemicals. Stearyl bromide is also used as an intermediate to manufacture organic chemicals and Pharmaceuticals. Some of its properties are given below: Stearyl bromide is a white to light yellow solid. Synonyms: 1-Bromooctadecane, n-Octadecyl bromide Chemical formula: CH3(CH2)i6CH2Br(Ci8H37Br) Molecular weight: 333.39 Density at 25°C: 0.976g/ml Boiling Point(12 mm Hg): 214-216°C Melting Point: 25-30°C Stearyl Bromide is not commercially available. Presently it is imported from other countries for indigenous industrial applications. There is no report available for the preparation of stearyl bromide. There is a need to develop a simple and cost effective method for the preparation and process development of 1-bromooctadecane which can be upscaled to manufacturing process and can be produced indigenously. OBJECT OF INVENTION The main object of the present invention is that it provides a new and simple method for the preparation of 1-bromooctadecane indigenously. Another object of the present invention is to provide a simple process for the preparation of 1-bromooctadecane which gives pure product in excellent yield for indigenous applications. Further object of the present invention is to provide a new process, the preparation of which involves the use of indigenously available chemicals to make the complete process cost effective. Still another object of the present invention is to provide a new process for the preparation of 1-bromooctadecane which does not require the use of any flammable or moisture-sensitive reagents. Still another object of the present invention is to provide a new process for the preparation of 1-bromooctadecane which can easily be upscaled. Still another object of the present invention is to provide a new process for the preparation of 1-bromooctadecane in which effluent load is minimum. SUMMARY OF INVENTION In order to achieve the afore mentioned objectives and obviate the drawbacks of the prior art present invention provides a process for the preparation of 1-bromooctadecane comprising the steps of: • reacting 1-octadecanol with hydrobromic acid in the presence of concentrated sulphuric acid to obtain crude 1-bromooctadecane. • washing the crude product with 3-6% wash liquid and water. • purifying said crude product by vacuum distillation to obtain atleast 95% of 1-bromooctadecane. Example 1 To a 1L two-necked round bottom flask equipped with water condenser and mechanical stirrer, 190 ml of 48% hydrobromic acid was taken. To this 25 ml of concentrated sulphuric acid (98%) was added through the side neck through a pressure - equalizing funnel in portions with stirring (some hydrogen bromide gas may liberate) and then 270g of 1-octadecanol (stearyl alcohol) followed by another 25 ml of concentrated sulphuric acid (98%) were added with constant stirring. The mixture was refluxed at 90°C with continuous stirring for 8 hours; after refluxing at said temperature, the mixture was cooled to room temperature (25°C) and transferred to a separating funnel. The stearyl bromide product was separated and the crude product was washed with 5% sodium hydrogen carbonate solution or sodium carbonate solution and water successively and further purified by vacuum distillation. 320g of stearyl bromide was obtained. The purity was > 99%by GC analysis. Example 2 To a 1 L two-necked round bottom flask equipped with water condenser and mechanical stirrer, 100 ml of 48% hydrobromic acid was taken. To this 13 ml of concentrated sulphuric acid (98%) was added through the side neck through a pressure -equilizing funnel in portions with stirring (some hydrogen bromide gas may liberate) and then 125g of 1-octadecanol (stearyl alcohol) followed by another 12 ml of concentrated sulphuric acid (98%) were added with constant stirring. The mixture was refluxed at 90°C with continuous stirring for 8 hours; after refluxing at said temperature, the mixture was cooled to room temperature (25°C), and transferred to a separating funnel. The stearyl bromide product was separated and the crude product was washed with 5% sodium hydrogen carbonate solution or sodium carbonate solution and water successively and further purified by vacuum distillation. 150g of stearyl bromide was obtained. The purity was >99% by GC analysis. DETAILED DESCRIPTION OF INVENTION According to the present invention, a process has been provided for the preparation of 1-bromooctadecane. The process involves one-step conversion of stearyl alcohol into stearyl bromide using hydrogen bromide generated in situ using hydrobromic acid and sulphuric acid. The overall yield and purity of 1-bromooctadecane obtained are 95-98% and >99% respectively. The process is simple to upscale. The process of the present invention for the preparation of 1-bromooctadecane comprises the following procedure: To a two-necked round bottom flask equipped with water condenser and mechanical stirrer, 35-50% by weight of 48% hydrobromic acid preferably 40-45% by weight was taken. To this 10-20% by weight of concentrated sulphuric acid(98%) preferably 14-16% by weight was added in portions with stirring(some hydrogen bromide gas was liberated during this addition) and then 35-45% by weight of 1-octadecanol (stearyl alcohol) preferably 39-43% by weight followed by 10-20% by weight of concentrated sulphuric acid (98%) preferably 14-16% by weight were added with stirring. The mixture was refluxed at 70-100°C preferably 80-90°C with continuous stirring for 6-12 hours preferably 8-10 hours; after refluxing at said temperature, the mixture was cooled to ambient temperature (25°C), and the stearyl bromide product was separated using separating funnel. The crude product was washed with 5% sodium hydrogen carbonate solution or sodium carbonate solution and water successively and further purified by vacuum distillation yield >95% was obtained. Present invention will now be explained with the help of examples; however, the scope of the invention should not be limited to these examples. We Claim: 1. A process for the preparation of 1-bromooctadecane comprising the steps of: i. reacting 1 -octadecanol with hydrobromic acid in the presence of concentrated sulphuric acid to obtain crude 1-bromooctadecane. ii. washing the crude product with 3-6% wash liquid and water, iii. Purifying said crude product by vacuum distillation to obtain atleast 95% of 1-bromooctadecane. 2. A process as claimed in claim 1, wherein the hydrobromic acid used is 35 to 50% by weight, preferably 40 to 45% by weight. 3. A process as claimed in claim 1, wherein the concentrated sulphuric acid used in step (t) is 10 to20% by weight, preferably 14 to 16% by weight. 4. A process as claimed in claim 1, wherein 1-octadecanol used is 35 to 45% by weight, preferably 39 to 43% by weight. 5. A process as claimed in claim 1, wherein the reaction mixture in step (i) is refluxed at a temperature of 70-100°C with continuous stirring for 6-12 hours. 6. A process as claimed in claim 1, wherein the wash liquid is selected from a group consisting of alkali carbonate and alkali hydrogen carbonate and preferably sodium carbonate and sodium hydrogen carbonate. 7. A process of preparing 1-bromooctadecane substantially as herein described with reference to the foregoing examples.

Full Text

FIELD OF INVENTION
This invention relates to a process for the preparation of 1-bromooctadecane from indigenously available stearyl alcohol.
BACKGROUND OF INVENTION
Stearyl bromide is used as an important raw material for the preparation of surfactant, UV absorbing agent, and photographic chemicals. Stearyl bromide is also used as an intermediate to manufacture organic chemicals and Pharmaceuticals. Some of its properties are given below:
Stearyl bromide is a white to light yellow solid.
Synonyms: 1-Bromooctadecane, n-Octadecyl bromide
Chemical formula: CH3(CH2)i6CH2Br(Ci8H37Br)
Molecular weight: 333.39
Density at 25°C: 0.976g/ml
Boiling Point(12 mm Hg): 214-216°C
Melting Point: 25-30°C
Stearyl Bromide is not commercially available. Presently it is imported from other countries for indigenous industrial applications. There is no report available for the preparation of stearyl bromide.
There is a need to develop a simple and cost effective method for the preparation and process development of 1-bromooctadecane which can be upscaled to manufacturing process and can be produced indigenously.
OBJECT OF INVENTION
The main object of the present invention is that it provides a new and simple method for the preparation of 1-bromooctadecane indigenously.

Another object of the present invention is to provide a simple process for the preparation of 1-bromooctadecane which gives pure product in excellent yield for indigenous applications.
Further object of the present invention is to provide a new process, the preparation of which involves the use of indigenously available chemicals to make the complete process cost effective.
Still another object of the present invention is to provide a new process for the preparation of 1-bromooctadecane which does not require the use of any flammable or moisture-sensitive reagents.
Still another object of the present invention is to provide a new process for the preparation of 1-bromooctadecane which can easily be upscaled.
Still another object of the present invention is to provide a new process for the preparation of 1-bromooctadecane in which effluent load is minimum.
SUMMARY OF INVENTION
In order to achieve the afore mentioned objectives and obviate the drawbacks of the prior art present invention provides a process for the preparation of 1-bromooctadecane comprising the steps of:
• reacting 1-octadecanol with hydrobromic acid in the presence of
concentrated sulphuric acid to obtain crude 1-bromooctadecane.
• washing the crude product with 3-6% wash liquid and water.
• purifying said crude product by vacuum distillation to obtain atleast
95% of 1-bromooctadecane.

Example 1
To a 1L two-necked round bottom flask equipped with water condenser and mechanical stirrer, 190 ml of 48% hydrobromic acid was taken. To this 25 ml of concentrated sulphuric acid (98%) was added through the side neck through a pressure - equalizing funnel in portions with stirring (some hydrogen bromide gas may liberate) and then 270g of 1-octadecanol (stearyl alcohol) followed by another 25 ml of concentrated sulphuric acid (98%) were added with constant stirring. The mixture was refluxed at 90°C with continuous stirring for 8 hours; after refluxing at said temperature, the mixture was cooled to room temperature (25°C) and transferred to a separating funnel. The stearyl bromide product was separated and the crude product was washed with 5% sodium hydrogen carbonate solution or sodium carbonate solution and water successively and further purified by vacuum distillation. 320g of stearyl bromide was obtained. The purity was > 99%by GC analysis.
Example 2
To a 1 L two-necked round bottom flask equipped with water condenser and mechanical stirrer, 100 ml of 48% hydrobromic acid was taken. To this 13 ml of concentrated sulphuric acid (98%) was added through the side neck through a pressure -equilizing funnel in portions with stirring (some hydrogen bromide gas may liberate) and then 125g of 1-octadecanol (stearyl alcohol) followed by another 12 ml of concentrated sulphuric acid (98%) were added with constant stirring. The mixture was refluxed at 90°C with continuous stirring for 8 hours; after refluxing at said temperature, the mixture was cooled to room temperature (25°C), and transferred to a separating funnel. The stearyl bromide product was separated and the crude product was washed with 5% sodium hydrogen carbonate solution or sodium carbonate solution and water successively and further purified by vacuum distillation. 150g of stearyl bromide was obtained. The purity was >99% by GC analysis.

DETAILED DESCRIPTION OF INVENTION
According to the present invention, a process has been provided for the preparation of 1-bromooctadecane. The process involves one-step conversion of stearyl alcohol into stearyl bromide using hydrogen bromide generated in situ using hydrobromic acid and sulphuric acid.
The overall yield and purity of 1-bromooctadecane obtained are 95-98% and >99% respectively. The process is simple to upscale.
The process of the present invention for the preparation of 1-bromooctadecane comprises the following procedure:
To a two-necked round bottom flask equipped with water condenser and mechanical stirrer, 35-50% by weight of 48% hydrobromic acid preferably 40-45% by weight was taken. To this 10-20% by weight of concentrated sulphuric acid(98%) preferably 14-16% by weight was added in portions with stirring(some hydrogen bromide gas was liberated during this addition) and then 35-45% by weight of 1-octadecanol (stearyl alcohol) preferably 39-43% by weight followed by 10-20% by weight of concentrated sulphuric acid (98%) preferably 14-16% by weight were added with stirring. The mixture was refluxed at 70-100°C preferably 80-90°C with continuous stirring for 6-12 hours preferably 8-10 hours; after refluxing at said temperature, the mixture was cooled to ambient temperature (25°C), and the stearyl bromide product was separated using separating funnel. The crude product was washed with 5% sodium hydrogen carbonate solution or sodium carbonate solution and water successively and further purified by vacuum distillation yield >95% was obtained.
Present invention will now be explained with the help of examples; however, the scope of the invention should not be limited to these examples.

We Claim:
1. A process for the preparation of 1-bromooctadecane comprising the steps of:
i. reacting 1 -octadecanol with hydrobromic acid in the presence of
concentrated sulphuric acid to obtain crude 1-bromooctadecane.
ii. washing the crude product with 3-6% wash liquid and water,
iii. Purifying said crude product by vacuum distillation to obtain atleast 95% of 1-bromooctadecane.
2. A process as claimed in claim 1, wherein the hydrobromic acid used is 35 to 50% by weight, preferably 40 to 45% by weight.
3. A process as claimed in claim 1, wherein the concentrated sulphuric acid used in step (t) is 10 to20% by weight, preferably 14 to 16% by weight.
4. A process as claimed in claim 1, wherein 1-octadecanol used is 35 to 45% by weight, preferably 39 to 43% by weight.
5. A process as claimed in claim 1, wherein the reaction mixture in step (i) is refluxed at a temperature of 70-100°C with continuous stirring for 6-12 hours.
6. A process as claimed in claim 1, wherein the wash liquid is selected from a group consisting of alkali carbonate and alkali hydrogen carbonate and preferably sodium carbonate and sodium hydrogen carbonate.
7. A process of preparing 1-bromooctadecane substantially as herein described with reference to the foregoing examples.

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Patent Number

271029

Indian Patent Application Number

2330/DEL/2007

PG Journal Number

06/2016

Publication Date

05-Feb-2016

Grant Date

29-Jan-2016

Date of Filing

07-Nov-2007

Name of Patentee

DIRECTOR GENERAL, DEFENCE RESEARCH & DEVELOPMENT ORGANISATION

Applicant Address

DRDO,MINISTRY OF DEFENCE ROOM NO.348, B-WING DRDO BHAVAN, RAJAJI MARG NEW DELHI 110 011

Inventors:

#	Inventor's Name	Inventor's Address
1	AMBATI NARASIMHA RAO	SYNTHETIC CHEMISTRY DIVISION, DRDE, JHANSI ROAD, GWALIOR-474 002
2	PRADEEP KUMAR GUPTA	SYNTHETIC CHEMISTRY DIVISION, DRDE, JHANSI ROAD, GWALIOR-474 002
3	SUMAN AWASTHI	SYNTHETIC CHEMISTRY DIVISION, DRDE, JHANSI ROAD, GWALIOR-474 002
4	KUMARAN GANESAN	SYNTHETIC CHEMISTRY DIVISION, DRDE, JHANSI ROAD, GWALIOR-474 002
5	MAHABIR PARSHAD KAUSHIK	PROCESS TECHNOLOGY DEVELOPMENT DIVISION, DRDE, JHANSI ROAD, GWALIOR-474 002
6	KRISHNAMURTHY SEKHAR	DIRECTOR, DRDE, JHANSI ROAD, GWALIOR-474 002

PCT International Classification Number

C07C9/22; C07C1/22

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA