Title of Invention

A NOVEL PROCESS FOR IMPROVING THE PERFORMANCE OF SILICAGEL SUPPORTED INDUSTRIAL ETHYNYLATION CATALYST

Abstract The present invention discloses a novel process for improving the activity of industrial ethynylation catalyst generated from silicagel supported catalyst precursor, which comprises of: (i) mixing the said precursor with the oxide of an alkaline earth metal in definite proportions; (ii) packing the mixture obtained in step (i),in a stainless steel reactor maintained in the temperature range of 50-110 °C and (iii) passing formaldehyde and acetylene through the said reactor to generate the catalyst in-situ for ethynylation reaction.
Full Text FORM 2
THE PATENT ACT, 1970
(39 of 1970)
AND
THE PATENT RULES, 2003
COMPLETE SPECIFICATION
(See Section 10, Rule 13)

1. TITLE OF THE INVENTION

A NOVEL PROCESS FOR IMPROVING THE PERFORMANCE OF SILICAGEL SUPPORTED INDUSTRIAL ETHYNYLATION CATALYST.



2. APPLICANTS)
(a) Name:
(b) Nationality:
(c) Address:

M/s. HINDUSTAN ORGANIC CHEMICALS LIMITED
Indian
Mr. A. S. Didolkar, CMD
81, Maharshi Karve Road, MUMBAI - 400 002,
Maharashtra, India.


3. PREAMBLE TO THE DESCRIPTION :
COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it is to be performed :





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The method of the present invention can be used to enhance the activity of silicagel supported catalysts used for industrial ethynylation of formaldehyde with acetylene at low pressures. The type of reactor used is continuous packed bed system. Due to limitations of lower activity and life of for silicagel supported catalysts, the performance of the latter is adversely affected. This can be improved by the method of the present invention by incorporating to the catalyst precursor and generating the catalyst in-situ by passing a mixture of formaldehyde and acetylene through the catalyst bed-
PRIOR ART:
Various silicagel supported catalysts for ethynytetion of formaldehyde with acetylene at moderate temperature (50° -140 °C) and pressures in the range of 1-30 kg/cm2 are summarized, [S. S. Kale et al., Ind. Eng. Chem. Prod. Res. Dev., 20, p. 310, 1981]. The reactors of trickle bed or slurry reactor types have been reported. Comparison of the performance of magnesium silicate supported catalyst with that of granular silicagel supported one is also reported at moderate temperature (30° -100 °C ) and pressure (1-5 kg/cm2), performance in trickle bed reactors is also reported [US Patent No. 2, 871, 273 E. A. Behn, Lake Jackson, Dow Chemicals Co., USA, 1959]. Bothe the supports are reported for ethynylation reaction under similar conditions of temperature and pressure [A. Germain, in "Mass transfer with chemical reaction in multiphase systems" Vol. II, edited by E. Alper (Martinus Nijhoff Publications, The Hague), pp.29-31, 1983].
Magnesium silicate supported powdered catalysts in slurry reactors for ethynylation reaction at higher pressures were also reported [J. J. Chu et. al., Appl. Catal. A: General, 97, p. 123, 1993]. The said reaction with the said catalyst at lower pressures were also reported [US Patent No.3, 920, 759, E. V. Hort, GAF corporation, USA, 1975; US Patent No. 4, 119, 790 E. V. Hort, GAF Corporation, USA, 1978; F. W. Chang et. al., Chem. Eng. Sci., 47, p. 3793, 1992]. The catalyst preparation involved impregnation of the support with the
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nitrates of copper and bismuth, followed by heating and then roasting to convert the nitrates into corresponding oxides to obtain the catalyst precursor [US patent No. 4, 119, 790 E. V. Hort, GAF Corporation, USA, 1978]. The catalyst gets generated in-situ by passing a mixture of formaldehyde and acetylene through the catalyst precursors. The magnesium silicate supported catalysts are found to exhibit better performance than those containing silicagel supports.
The present invention discloses a novel process for improving the activity of silicagel supported industrial ethynylation catalyst as hereinbefore described.
DESCRIPTION OF THE INVENTION :
Industrial ethynylation catalyst precursor supported on silicagel is prepared from granulated silicagel support having a particle size range, 2 to 8 mm (preferably 2 to 3 mm) diameter and surface area, 200 to 500 m2/g. The copper and the bismuth contents of the catalyst precursor are 10 - 12 wt% and 2.0 - 3.5 wt% respectively.
The catalyst is generated in-situ by passing formaldehyde and acetylene through a packed bed stainless steel reactor containing the catalyst precursor in a temperature range of 50° to 110 °C and a pressure of 1 kg/cm2 to 2 kg/cm2. The concentration of formaldehyde used is 5- 25 wt% having a pH of 2 to 10, preferably 5 to 8 and methanol content of 0.5 - 3.0 wt%. Thereafter, the ethynylation reaction is carried out in the above packed bed reactor continuously under the said conditions.
The present invention discloses a novel process comprising of mixing magnesium oxide (in the form of lightly calcined magnesite) in definite proportions with the silicagel supported industrial ethynylation catalyst precursor. The catalyst is generated in-situ under the said conditions. Thereafter, the
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ethynylation reaction is carried out in the above packed bed reactor continuously under the said conditions.
The quantity of magnesium oxide in the catalyst precursor mixture is varied in the range of 5 to 50 wt%. The reactor outlet acidity (as formic acid), water content as well as magnesium content are monitored.
The initial acidity at the reactor outlet is observed to decrease significantly during initial catalyst generation period for all the catalysts containing magnesium oxide. The acidity is highest during this period for normal silicagel supported catalyst. Hence, the role of magnesium oxide in arresting the acidity is evident.
The novel catalyst prepared in this manner enhances the activity of normal silicagtel supported catalyst considerably from 90 - 110 g 2-butyne-1,4-diol/lit catalyst/day at various proportions of magnesium oxide. However, the best and consistent performance is obtained for a composition containing magnesium oxide in the range of 5 to 15 wt%. In this case, the catalyst activity achieved is in the range of 250 - 400 g 2-butyne-1,4-diol/lit catalyst / day upon continuous running for longer durations (312 - 600 hr).
The invention is further described with reference to the following examples which do not limit the scope of the invention.
Example -1
Silicagel Supported Industrial Ethynylation Catalyst
The industrial ethynylation catalyst was prepared by known method using siliagel support, having surface area, 300 to 350 m2/g and particle size, 2 to 3 mm granules, with the following specifications :
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Copper content Bismuth content Fe203 content Sulphur content Chloride content

11.02 wt%; 3.45 wt%;
0.02 wt% maximum; 0.02 wt% maximum; 150 ppm maximum

Different precursor compositions for various ethynylations catalysts are described as follows :
For Catalyst- K : (As such, without MgO)
For this charge, 800 g the silicagel supported industrial ethynylation catalyst precursor as such, were packed in a stainless steel reactor.
For Catalyst - G : (with 12.5 wt% MgO)

For this charge, 700 g of the above catalyst were mixed 100 g of Magenesium Oxide (Light Calcined Magnesite) having the following specifications :
Form
Loss on ignition
Fe203
CaO
Si02
Al203
MgO
lumps, 3-6 mm size;
2.0 wt% max;
0.3 wt% max;
1.5 wt% max;
8.5 wt% max;
0.35 wt% max;
87 wt% max.
and the mixture was packed (total quantity 800 g) in a stainless steel reactor having arrangements for continuous feeding of aqueous formaldehyde solution and acetylene as well as separate arrangement for gaseous feed and withdrawl of liquid products and recycle acetylene.
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For Catalyst - T : (with 22 wt% MgO)
For this charge, 700 g of the above catalyst were mixed with 200 g of Magnesium Oxide of similar specifications described hereinbefore. The mixture (total quantity 900 g), was packed in a stainless steel reactor.
For Catalyst - R : (with 30wt% MgO)
For this charge, 600 g of the above catalyst were mixed with 268 g of Magnesium Oxide of similar specifications described hereinbefore and the mixture was packed (total quantity 868 g) in a stainless steel reactor.
For all precursor compositions the catalysts were generated in-situ by the following steps :
i) acetylene gas was introduced after initial purging with nitrogen gas;
ii) the reactor was maintained at 85° to 95 °C ;
iii) the reactor pressure was 200 - 500 mm water gauge;
iv) the feed concentration was 20 - 25 wt% aqueous formaldehyde solution having 5 to 8 pH and a methanol content in the range of 0.5 to 3 wt%. The reaction was carried out under the said experimental conditions as hereinbefore described for the generation of catalyst.
The reaction product 2-butyne-1,4-diol was continuously collected from the
reactor outlet and analysed periodically for formaldehyde, acidity (as formic acid),
magnesium and water contents. Continuous runs were carried out for the
following periods :
Catalyst-T ' 312 hr
Catalyst - R 528 hr
Catalyst-G 600 hr
Catalyst-K 600 hr
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The followtng examples (II, III and IV) illustrate the trends of various parameters for continuous running of various catalysts (, G, T and R) under the reaction conditions mentioned in Example I.
Example -II
(This example is given for acidity contents in the product) The acidity (wt% as formic acid) in the product for various catalysts prepared in Example I is presented in Table 1. From Table 1, it is clear that the initial acidity is significantly lower during an initial period of about 120 hrs (corresponding to catalyst reduction), for the catalysts containing MgO (viz catalysts G, T and R) whereas the same is significantly higher in case of silicagel supported industrial ethynylation catalyst without any MgO (catalyst -K).
Example - III
(This example is given for magnesium contents in the product) The magnesium content (wt%) in the product for various catalysts prepared in Example I is illustrated in Table 2. The results indicate higher magnesium content in the product in case of Catalysts - T and R as compared to Catalyst - G. The latter shows nearly steady trend of magnesium content throughout the testing period.
Example - IV
(This example is given for catalyst activity)
The activities of various catalysts prepared in Example I are described as follows:
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Catalyst - K (without MgO content):
This catalyst showed an average activity of 97 g 2-butyne-1,4-dial / lit catalyst / day for 600 hr. Towards the end of this period, the activity decreased considerably to 23 g 2-butyne-1,4-diol / lit catalyst/day.
Catalyst - G (with 12.5 wt% MgO):
This catalyst showed most consistent performance. The average catalyst activity achieved for the catalyst - G was 370 g 2~butyne-1, 4-diol/lit catalyst/day for a 360 hr period. Thereafter, the fall in catalyst activity was quite less. The average activity for a 600 hr period came to 253 g 2-butyne-1, 4-diol/lit catalyst/day.
Catalyst - T (with 22 wt% MgO)
This catalyst showed an average activity of 297 g, 2-butyne-1,4-diol/lit catalyst/day for 216 hr period. Thereafter, the activity decreased rapidly to about 150 g 2-butyne-1,4-diol/lit catalyst / day.
Catalyst - R (with 30 wt% MgO)
This catalyst showed a better activity i.e. 310 g 2-butyne-1, 4-diol/lit catalyst/day for 288 hr period. In this case, the activity decreased rapidly to about 40 g 2-butyne-1,4-diol/lit catalyst/day.
The catalyst - G (with 12.5 wt% MgO) exhibited consistently a higher activity for low-pressure continuous ethynylation reaction for a longer duration. This is attributed to optimal quantity of magnesium oxide in the normal silicagel supported catalyst
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We claim :
1. A novel process for improving the performance of industrial
ethynylation catalyst generated from silicagel supported catalyst
precursor, which comprises of:
(i) mixing the said precursor with the oxide of an alkaline earth metal in definite proportions ;
(ii) packing the mixture obtained in step (i), in a stainless steel reactor maintained in the temperature range of 50° -100 °C;
(iii) passing formaldehyde and acetylene through the said reactor, to generate the catalyst in-situ for ethynylation reaction.
2. A process as claimed in claim 1, wherein the silicagel supported catalyst precursor contains oxides of copper and bismuth as active components.
3. A process as claimed in claims 1 and 2, wherein the copper content is in the range of 10 -12 wt% and the bismuth content is in the range of 2.0-3.5 wt%.
4. A process as claimed in step (i) of claim 1, wherein the said alkaline earth metal is magnesium.
5. A process as claimed in step (i) of claim 1, wherein particle size of the said oxide is 2 - 8 mm.
6. A process as claimed in step (i) of claim 1, wherein quantity of the said oxide in the mixture is 5 to 50 wt%.
7. A process as claimed in step (iii) of claim 1, wherein the concentration of formaldehyde is 5 - 30 wt%.
8. A process as claimed in step (iii) of claim 1, wherein the pH of the formaldehyde is 2 - 10.
9. A process as claimed in step (iii) of claim 1, wherein the methanol content of the formaldehyde is 0.5 - 3.0 wt%.
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10. A process as claimed in claim 1, wherein the catalyst is generated in-situ at a tow pressure of 1 - 2 kg / cm2
11. A process for improving the performance of industrial ethynylation catalyst generated from the silicagel supported catalyst precursor, substantially described herein with reference to examples I to IV in the specification.
Dated this day of 2008.
For and on behalf of M/S. HIINDUSTAN ORGANIIC CHEMICALS LIM ITED
(ARVIND SHRIRAM DIDOLKAR) CHAIRMAN & MANAGING DIRECTOR
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Documents:

1523-mum-2008-abstract.doc

1523-mum-2008-abstract.pdf

1523-MUM-2008-CLAIMS(AMENDED)-(24-1-2012).pdf

1523-MUM-2008-CLAIMS(AMENDED)-(27-4-2012).pdf

1523-mum-2008-claims.doc

1523-mum-2008-claims.pdf

1523-MUM-2008-CORRESPONDENCE(10-10-2011).pdf

1523-MUM-2008-CORRESPONDENCE(14-9-2012).pdf

1523-MUM-2008-CORRESPONDENCE(17-8-2012).pdf

1523-MUM-2008-CORRESPONDENCE(20-3-2012).pdf

1523-MUM-2008-CORRESPONDENCE(23-12-2011).pdf

1523-MUM-2008-CORRESPONDENCE(24-2-2011).pdf

1523-MUM-2008-CORRESPONDENCE(26-9-2012).pdf

1523-mum-2008-description(complete).doc

1523-mum-2008-description(complete).pdf

1523-mum-2008-form 1.pdf

1523-mum-2008-form 18.pdf

1523-mum-2008-form 2(18-7-2008).pdf

1523-mum-2008-form 2(title page).pdf

1523-mum-2008-form 2.doc

1523-mum-2008-form 2.pdf

1523-mum-2008-form 3.pdf

1523-mum-2008-form 5.pdf

1523-mum-2008-form 9(18-7-2008).pdf

1523-MUM-2008-REPLY TO EXAMINATION REPORT(24-1-2012).pdf

1523-MUM-2008-REPLY TO HEARING(27-4-2012).pdf

FORM9.TIF


Patent Number 254227
Indian Patent Application Number 1523/MUM/2008
PG Journal Number 41/2012
Publication Date 12-Oct-2012
Grant Date 04-Oct-2012
Date of Filing 18-Jul-2008
Name of Patentee M/s. HINDUSTAN ORGANIC CHEMICALS LIMITED
Applicant Address RASAYANI, DIST. RAIGAD-410207,
Inventors:
# Inventor's Name Inventor's Address
1 SHINDE BAPURAO SIDRAM RASAYANI, DIST. RAIGAD, PIN-410207,
2 SATHE AMOD MADHUKAR RASAYANI, DIST. RAIGAD, PIN-410 207,
PCT International Classification Number B01J29/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA