Title of Invention

"A PROCESS FOR THE PREPARATION OF SECONDARY ALCOHOLS BY OXIDATION OF N-PARAFFINS USING A CATALYST SYSTEM"

Abstract This invention relates to a process for the preparation of secondary alcohols in liquid phase by oxidation of n-paraffins with oxygen, air or oxygen containing inert gas which comprises Contacting the n-paraffin with the catalyst as herein described the metal part of the catalyst being selected from the Group 11(a) of periodic table of elements, preferably Ca, Mg or Ba and organic legend with metal is a fatty ester group of Cio-C20 carbon chain, preferably laurate, palmitate or stearate; wherein the said catalyst to n-paraffin ratio is 10 to 1000 ppm; Contacting the resulting mixture with air or oxygen containing inert gas such as nitrogen and boric acid or borate ester at space velocity in the range 1-250 h-1, temperature in the range of 150-250°C, and pressure in the range of 0.01-10 bar for a period of l-10h, wherein the boric acid or borate ester concentration is 0.1 to 10% wt of the n-paraffin; Separating the secondary alcohol boric acid esters, unreacted n-paraffins unreacted boric acid by distillation; and Recovering the secondary alcohols by hydrolysis of borate ester; and recycling the unreacted n-paraffins, and boric acid in the step (a) and (b) above.
Full Text Background of the Invention
This invention relates to a catalyst and a process for preparing secondary alcohols
using the catalyst. The invention is particularly concerned with a catalyst comprising
"of metal salt(s) of saturated fatty acids having carbon range from 10-20 which when
used as catalyst in the oxidation of n-paraffins in presence of boric acid, dehydrated
boric acid or boric acid esters, selectively, yields secondary alcohols.
Fatty alcohols, having Ci2-C-i5 carbon chains and their derivatives are important
commercial products as plasticizers, surfactants and in the production of polymers,
monomers, lubricating oils. Viscosity improvers and pour point depressants greases
etc. Fatty alcohol derivatives are used to a great extent in the premium house hold
detergents for performance and environmental reasons. These surfactants are
readily biodegradable and are finding increased use in low phosphate and nonphosphate
detergertts. The alcohol provides the starting material for all types of
surfactants e.g. non-ionics anianics, catiaric and zwitterianics of C12-Q find
applications in consumer products e.g. Toothpaste, hair shampoos, carpet
shampoos and light duty house hold detergent. Polyethoxylates alcohols sulphates
and neutralized products gives anionic surfactants had wide applications as light
duty detergent and heavy duty house hold liquid & granular detergent.
Polyethoxylated alcohols have numerous industrial applications as wetting agents,
dispersing agents and emulsifiers.
It is well known in the literature that these fatty alcohols can be produced directly via
oxidation of n-paraffins. Studies to prepare fatty alcohols via oxidation of n-paraffins.
Studies to prepare fatty alcohols via oxidation of n-paraffins in presence of boric acid
and arsenous acids, aluminium and chromic hydroxides and potassium
permanganate are described in J. Soc. Chem. Ind. Jpn., 47, pp. 475-477, 1944; ibid-
46, pp. 765-7, 1943 and Ann. Chim. Appl., 39, pp. 311-20, 1949.
In all the above investigations the alcohol formation is accompanied by the formation
of large amount of by-products such as acids, esters and carboxyl compounds etc.,
resulting in a complex mixture of oxygenated compound; the isolation of alcohols
from such complex mixture is very difficult.
Bashkirov et.al. and Bashkirov and Kamzolkim (Proc. Acad. Sci. U.S.S.R. Chem.
Tech. Sec., 1, pp 118-119, 1956 and World Pet. Congr. 4, pp. 175-183, 1959)
described the process for oxidation of individual n-paraffins with nitrogen-oxygen
mixture containing 3.0 to 4.5% oxygen at 165 -170°C mixture containing 3.0 to 4:5%
oxygen in liquid phase at 165-170°C in presence of boric acid or -to produce
secondary fatty alcohols with same number of carbon atoms and the same skeletal
structure of the starting paraffin. The yield of alcohols was reported to be about 70%
of the n-paraffins feedstock.
Various boron derivatives e.g. tributoxy boroxine, tributoxy borane, boron trioxide
with or without lithium oxide have also been reported to be used in the oxidation of nparaffin
to alcohols. The yield of alcohols were however low in the range of 16-21%
at 10-30% paraffin conversion.
In US patent no. 3,238,238 (1966), use of oxidation catalysts such as Mg, Co or V
napthenate, oleate or acetate with t-butylborate and an inert diluent oxidize aliphatic
hydro-carbons to alcohols at 130-180°C. .
Japanese patent no 6,27,267 (1987) describes a'process to prepare alcoholic waxes
by liquid-phase oxidation of C2o-C6o paraffins waxes with oxygen in presence of
1.0:0.5 - 1.0 mol mixture of H3BO3 and B2O3; about 73% conversion to alcohols
were reported.
. A process for preparing secondary alcohols by oxidation of Ci0-C3o n-paraffins using
finely divided orthoboric acid at 156-60°C has been claimed to given about 70%
selectivity to alcohol formation. (Neth. Patent appl. 6, 50g857 (1966)).
Use of promoters such as ammonia, amines, imides, amides, pyridine etc. were
found to promote the oxidation of alkanes or cycloalkane with boric acid or dehydrate
boric acid (French patent no - 1,501,429 (1967)).
US patent no 4,970,346 (1990) disclose a process for the production of detergent
range alcohols and ketones from Cio-Cia alkanes by reacting with a hydroperoxide in
the presence of dicyano bis (1,10 = phenanthrolene) iron (II) catalyst.
-3-
The use of transition metal catalysts to prepare Cm-Cia alcohols have been
described in US patent no's-4,978,800 (1990) and 4,978,799 (1990); the conversion
to alcohols obtained were low (~ 2% wt) even at longer reaction time of 20 h.
The oxidation of alkanes in presence of boric acid or esters to produce alcohols was
claimed to be accelerated by use of 50-100 ppm transition metal as a 3dcarboxylate.
(Brit. Patent no -1,035,624 (1966)).
Various oxidation catalysts were reported in literature including Mn-Naphthenate
MnOa, KMnO4, t-Butyl per oxide, Co-strearate, TiCU, etc. to increase the yield of
Borate ester. Amine & NHa were used to reduce the deactivation effect of aromatics.
Use of additives such as boron trioxide, tributyl oxyboroxine, oxybis (di-n-butoxy
borane) and t-butyl hydroperoxide is known to increase, the formation of alcohols but
' only marginally.
In the hitherto known processes, generally the yield of alcohols and conversion of
n-paraffms perpass is low and range between 16-21% and 10-30% respectively. The
selectivity of alcohols and ketones combined together.range between 80-90% based
on paraffin. Further in these processes there is always a possibility of coagulation of
boric acid or boric acid esters due to their poor solubility and density difference
between boric acid and hydrocarbon phase. This leads to poor activity of boric acid
and lower yield of alcohols.
The main object of the present invention is to provide a catalyst that provide an
improved process for the oxidation of paraffins. It is an object of the present
invention to provide a process in which the use of the said catalyst increases the
yield of secondary alcohols in the oxidation of paraffins. It is yet another object of the
present invention to provide catalyst that increases the rate of initiation of peroxides
in the free radical oxidation of paraffins and thereby increasing the formation and
selectivity of secondary alcohols.
STATEMENT OF INVENTION
According to this invention there is provided a process for the preparation of secondary alcohols in liquid phase by oxidation of n-paraffins with oxygen, air or oxygen containing inert gas which comprises Contacting the n-paraffin with the catalyst as herein described the metal part of the catalyst being selected from the Group 11(a) of periodic table of elements, preferably Ca, Mg or Ba and organic legend with metal is a fatty ester group of C10-C20 carbon chain, preferably laurate, palmitate or stearate; wherein the said catalyst to n-paraffin ratio is 10 to 1000 ppm; Contacting the resulting mixture with air or oxygen containing inert gas such as nitrogen and boric acid or borate ester at space velocity in the range 1-250 h-1, temperature in the range of 150-250°C, and pressure in the range of 0.01-10 bar for a period of 1-1 Oh, wherein the boric acid or borate ester concentration is 0.1 to 10% wt of the n-paraffin; Separating the secondary alcohol boric acid esters, unreacted n-paraffins unreacted boric acid by distillation; and Recovering the secondary alcohols by hydrolysis of borate ester; and recycling the unreacted n-paraffins, and boric acid in the step (a) and (b) above.
SUMMERY OF THE INVENTION
In accordance with the present invention, it has been found that catalysts comprising of metal salts of long chain fatty acids exhibit very high activity and selectivity, when used to produce secondary alcohols via oxidation of n-paraffins in presence of boric acid/boric acid ester. The metal part of the catalyst of the catalyst is a metal selected from Group-II (a) of her Periodic Table of Elements. The fatty acid part is selected from C10-C20 saturated fatty acids. The catalytic salts described in the present invention can be prepared by conventional technique used in the preparation of metal salts of fatty acids.
The inventors of the present invention conducted repeated research regarding the use of Group-11(a) metal salts of fatty acids as catalyst to enhance rate of oxidation of n-paraffin and selectivity to secondary alcohols in presence of boric acid/fatty acid borate esters and found that the fatty acid salts of Mg, Ca or Ba are particularly useful in enhancing the rate of initiation step in oxidation of n-paraffins, using molecular oxygen/air or Nitrogen oxygen mixture, and selectivity to secondary alcohols.
The present further relates to the application of Group-II (a) metal salts of fatty acids and provides a process to oxidize n-paraffins with 02/air/nitrogen and oxygen mixture in presence of boric acid under moderate operating conditions to selectively produce secondary alcohols.
The oxidation reaction was carried out in cylindrical reactor having a sintered disc at the bottom to bubble the N2 + 02 mixture. The reactor was connected to a reflex condenser through Dean and Stark receiver to remove water. The paraffin feed along with the catalyst is taken in the reactor while N2 + 02 mixture of known concentration is bubbled through the paraffin at a required rate, space velocity ranging between 1-250 h-1. The concentration of the catalyst used is in the range of 10 to 1000 ppm of n-paraffins. The contents of the reactor is heated to the desired temperature and then boric acid 0.1 to 10 wt% of n-paraffin is added to it; the reaction is continued and the water form the reactor is removed with the help of Dean and stark separator. After the reaction is over product is cooled and taken out in a RB flask. Unreacted paraffin is removed under reduced pressure to the extent
-fpossible.
The extent & yield of the alcohols were .monitored in terms of the yield of
Borate ester. The borate ester left as residue is hydrolysed with equal quantity of
water at reflux temperature. The aqueous layer is evaporated to recover boric acid.
The organic portion is digested with alkali to remove organic acid which can be
recovered by neutralization of aqueous portion. The organic portion is again distilled
to recover the secondary alcohols.
It will be apparent from the foregoing that the present invention provides a catalyst
which is active and selective for producing secondary alcohols via oxidation of
n-paraffins. Moreover the catalyst of the present invention which comprises a salt of
Group-ll(a) metal and a long chain fatty acid having C-i2-C2o carbon atoms preferably
laurate, palmitate or stearate is unexpectedly active and selective for oxidation of nparaffins
to produce secondary alcohols.
It was found that the oxidation reaction of n-paraffins jrv presence of the catalyst of
the present invention follows the free radical mechanism comprising of initiation,
propagation and termination steps. The overall rate of reaction is controlled by
transfer of oxygen through the gas-liquid interface. The catalyst of the present
invention enhances the gas-liquid interfacial area and in turn increases the rate of
initiation i.e. formation of peroxides. The increased rate of peroxide formation further
increases the formation of borate esters which is an equilibrium reaction.
The invention will be described in more details with reference to the following
' examples. These examples, however, are not to be construed to limit the scope of
the invention.
Although the invention has been described in conjunction with examples and by
reference to the embodiments thereof, it is evident that many alternatives,
modifications, and variations will be apparent to those skilled in the art in light of the
foregoing description, accordingly it is intended in the invention to embrace these
and all such alternatives, variations, and modifications as may fail within the spirit
and scope of the appended claimsExample-1
100 g of the n-paraffins mixture was taken in a cylindrical glass reactor having a
sintered disc at the bottom to bubble the oxygen nitrogen mixture' (oxygen content
4,5%). The oxygen nitrogen mixture was bubbled at the rate of 40 litre p«r hour and
the temperature from room temperature was increased to 180°C in 60 minutes.
Peroxide value of the paraffin mixture after 15 minutes was found to be 42.3 meq/kg.
3 g of boric acid in 25 ml of water was added to the system in 45 minutes. A second
lot of 3g boric acid in 25 ml water was again added in 45 minutes. The reaction was
continued for 180 minutes. The water along with same paraffin was collected in
Dean and Stark receiver which was removed from time to time while paraffin was
returned to the reactor. After the reaction was over the unreacted paraffin was
removed by distillation under reduced pressure and residue was hydrolysed with
'water to decompose the borate ester of secondary alcohol. The organic layer thus
obtained was refluxed with sodium hydroxide solution. After 15 minutes the organic
layer was washed with water and distilled to obtain secondary alcohol. The yield of
alcohol thus obtained was 18.9%.
Example-2
100 g of n paraffin mixture of Cio-Cu along with 0.041 g of Magnesium laurate was
taken in a cylindrical glass reactor as described in example-1. The mixture was
treated with oxygen; nitrogen mixture at a rate of 40 liter per/ hour and temperature
was slowly increased to 180°C in 60 min. The peroxide value of the paraffin mixture
after attaining the reaction temperature was found to be 127.8 meq./kg. 3 g of boric
acid in 25 ml water was added in 30 minutes. A second lot of 3 g boric acid in 25 ml
water was again added in 30 minutes and reaction was continued for 240 minutes.
After work up as described in example-1 the yield secondary of alcohols was found
to be 32.7%.
Example-3
The experiment was carried out as described in exaple-2 except that 0.0435 barium laurate was used in this experiment. The peroxide value observed, after 1:
minutes of attaining the temperature of 180°C was 96.85 meq/kg. The yield c
secondary alcohols obtained was 27.65%.
Example-4
The experiment was as described in example-3 except that 0.0422 g of calcium
laurate was in place of barium laurate. After 15 minutes of attaining the reaction
temperature (180°C) the peroxide value of the reaction mixture was found to be
195.35 meq/kg. The yield of alcohols was found to be 32.78%.'

]






WE CLAIM:
1. A process for the preparation of secondary alcohols in liquid phase
by oxidation of n-paraffins with oxygen, air or oxygen containing
inert gas which comprises:-
(a) Contacting the n-paraffin with the catalyst as herein described the metal part of the catalyst being selected from the Group 11(a) of periodic table of elements, preferably Ca, Mg or Ba and organic legend with metal is a fatty ester group of C10-C20 carbon chain, preferably laurate, palmitate or stearate; wherein the said catalyst to n-paraffin ratio is 10 to 1000 ppm;
(b) Contacting the resulting mixture with air or oxygen containing inert gas such as nitrogen and boric acid or borate ester at space velocity in the range 1-250 h-1, temperature in the range of 150-250°C, and pressure in the range of 0.01-10 bar for a period of 1-10h, wherein the boric acid or borate ester concentration is 0.1 to 10% wt of the n-paraffin;
(c) Separating the secondary alcohol boric acid esters, unreacted n-paraffins unreacted boric acid by distillation; and
(d) Recovering the secondary alcohols by hydrolysis of borate ester; and recycling the unreacted n-paraffins, and boric acid in the step (a) and (b) above.
2. The process as claimed in claim 1, wherein the catalyst to n-
paraffin ratio ranges preferably between 10 to 500 ppm.
3. The process as claimed in claim 1, wherein the pressure is in the
range of preferably 0.01-3 bar.
4. The process as claimed in claim 1, wherein the temperature is in
the range of preferably 170-200°C.
5. The process for the preparation of secondary alcohols by oxidation
of n-paraffins, wherein the catalyst system comprises catalyst
which is a metal salt of a saturated fatty acid containing carbon
atoms ranging between C10-C20 selected from palmitate or stearate.



Documents:

1131-del-2002-Abstract (24-06-2011).pdf

1131-DEL-2002-Abstract-(08-02-2010).pdf

1131-DEL-2002-Abstract-(24-06-2011).pdf

1131-del-2002-abstract.pdf

1131-del-2002-Amended Of Specification-(24-06-2011).pdf

1131-del-2002-Claims (24-06-2011).pdf

1131-DEL-2002-Claims-(08-02-2010).pdf

1131-del-2002-claims.pdf

1131-DEL-2002-Correspondence Others-(24-06-2011).pdf

1131-DEL-2002-Correspondence-Others (08-02-2010).pdf

1131-del-2002-Correspondence-others (24-06-2011).pdf

1131-del-2002-correspondence-others.pdf

1131-del-2002-correspondence-po.pdf

1131-DEL-2002-Description (Complete)-(08-02-2010).pdf

1131-del-2002-description (complete).pdf

1131-del-2002-Form-1 (24-06-2011).pdf

1131-DEL-2002-Form-1-(08-02-2010).pdf

1131-del-2002-form-1.pdf

1131-del-2002-form-18.pdf

1131-del-2002-form-2 (24-06-2011).pdf

1131-del-2002-form-2.pdf

1131-DEL-2002-Form-3-(08-02-2010).pdf

1131-del-2002-form-3.pdf

1131-DEL-2002-Form-5-(08-02-2010).pdf

1131-DEL-2002-GPA-(08-02-2010).pdf

1131-del-2002-gpa.pdf


Patent Number 248243
Indian Patent Application Number 1131/DEL/2002
PG Journal Number 26/2011
Publication Date 01-Jul-2011
Grant Date 29-Jun-2011
Date of Filing 11-Nov-2002
Name of Patentee NATIONAL RESEARCH DEVELOPMENT CORPORATION
Applicant Address ANUSANDHAN VIKAS, 20-22, ZAMROODPUR COMMUNITY CENTRE, KAILASH COLONY EXTENSION, NEW DELHI-110 048, INDIA.
Inventors:
# Inventor's Name Inventor's Address
1 A.K. BHATNAGAR INDIAN INSTITUTE OF PETROLEUM,P.O.IIP, MPHKAMPUR, DEHRADUN-248005, INDIA.
2 A.K. GUPTA INDIAN INSTITUTE OF PETROLEUM,P.O.IIP, MPHKAMPUR, DEHRADUN-248005, INDIA.
3 S.C. JOSHI INDIAN INSTITUTE OF PETROLEUM,P.O.IIP, MPHKAMPUR, DEHRADUN-248005, INDIA.
4 H.B. GOYAL INDIAN INSTITUTE OF PETROLEUM,P.O.IIP, MPHKAMPUR, DEHRADUN-248005, INDIA.
PCT International Classification Number B01J 23/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA