Title of Invention

PROCESS FOR SELECTIVE HYDROGENATION OF ALKYNES TO ALKENES OVER SINGLE METAL SUPPORTED CATALYSTS WITH HIGH ACTIVITY

Abstract The present invention relates to a process for selectively hydrogenating alkynes to alkenes over suitably supported single metal catalysts with high activity per unit of metal contents. It further elaborates selective hydrogenation of technical grades of 2-Butyne-1,4 diol produced from Reppe synthesis to 2-Butene-1,4 diol, with substantially lower Pd containing catalyst, amongst various commercially available Pd/ AI2Q3 catalysts, under tower hydrogen pressures ranging from 1 to 20 bar, at lower temperatures between 15 to 250° C, with GHSV 1 to 10,000 hֿ¹ and LHSV 0.001 to 10 h ֿ¹ , which can be scaled up more than 10 times in a continuous single tube or multi tubular reactor.
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

PROCESS FOR SELECTIVE HYDROGENATION OF ALKYNES TO ALKENES OVER SINGLE METAL SUPPORTED CATALYSTS WITH HIGH ACTIVITY.



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

M/8. 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.




Prior Art
Selective hydrogenation of alkynes to alkenes in general, and particularly that of 2-Butyne-1,4 diol (Butynediol) to 2-Butene-1,4 diof (Butenediol) as well as 2-Butene-1,4diol Butanediol), have been extensively studied and reported in the prior art
Palladium catalysts containing one or more additional metal containing catalysts
Palladium based catalysts, invariably with one or more additional metal contents on various catalyst supports have been reported for hydrogenation of alkynes to alkenes/ alkanes:
US Patent # 5,583,274 claims selective hydrogenation of alkynes present in alkenes streams along with sulphur containing compounds, by using Pd/Ag catalysts containing fluorides in the form of potassium fluoride on alumina supports, whereas US Patent # 6,127,310 claims the use of Pd along with Pb and alkali metal or alkali metal haiide as selectivity enhancers. US Patents # 7,045,670 and 7,408,091 claim liquid phase selective hydrogenation of alkynes absorbed in liquid stream on Zn promoted Pd catalyst on alumina support, with hydrogen containing more than 2000 ppm CO. US Patent #6,054,409 reports selective hydrogenation of unsaturated hydrocarbons in olefins with a Pd/Ag catalyst on a low surface area (2-20 m2/g) alumina carrier with pore volumes greater than 0.4 cc/g and a particular size range of the pores. As per US Patent #5,750,806 selective hydrogenation of alkynes (acetylenes) to alkenes is reported on Pd/Bi monoliths in Trickle bed, and as per US Patent # 6,365,790 B2 for Pd/Bi and Pd/Ag monoliths on Kanthal-fabric. Recent US Patent # 7,288,686 reveals complete removal of acetylenic compounds from hydrocarbon streams by using Pd with Ag/Zn/Bi/K in a fixed bed reactor.
Palladium catalysts containing oneor more additional metal are also reported in prior art for selective hydrogenation of 1,4 butynediol to 1,4 butenediol/1,4 butanediol:
Canadian Patent # 1,090,829 mentions palladium with lead in the form of lead acetate hydrate dozing to the reactor (autoclave). US Patent # 4,438,285 mentions use of Pd/Ru in a batch process, on activated carbon as well as alumina supports. US Patent # 5,714,644 mentions use of Pd with Cu, Zn, Cd, Ag in a batch process, US Patent # 6,528,689 reports Pd or Pd/Ni catalysts, whereas a latest US patent # US 2006/0094910 A1 reports Ni in combination with Pd. Palladium catalysts in the form of monofrths have also been reported: US Patent # 5,521,139 reports Pb as additional metal (element) to Pd in monolith gauges in a Trickle bed reactor for 1,4 butenediol product from 1,4 butynediol; Ind. Eng. Chem. Res. 44, 2005, 6148-6153 reports palladium in activated carbon filters as catalyst in an autoclave for hydrogenation of molten pure (otherwise solid) 1,4 butynediol to 1,4 butenediol.
Catalysts other than Palladium
Catalysts other than Pd, have also been reported for 1,4 butynediol hydrogenation in prior art. US Patent # 6,469,221 B1 reports a platinum based catalyst in a trickle bed reactor. US Patent # 6,528,689 B1 also reports a platinum as well as ZSM-5 based catalyst in an autoclave, whereas US Patent # 2006/0094910 reports Pt along with Pd/Ni for a batch process. US Patent # 6262,317 B1 reports Ni/Mo catalyst in a continuous bubble column up flow reactor. Catalysts Today, 93-95 (2004), 439-443 mentions about the same in supercritical CO2 with stainless steel wall of the autoclave, promoting the reaction.
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Catalysts supports


Out of the various catalysts referred to in the previous discussions, majority are with alumina supports (Canadian Patent* 1,090,829; US Patents * 5,583,274; 5,714,644; 6,054,409; 6,127,310; 6,262,317 B1; 7,045,670; 7,408,091; 7,288,686). Other supports e.g. Ca, Mg, Ba carbonates (US Patents* 5,714,644; 6,469,221 B1; 2006/0094910 A1); MgO (US Patent* 5,714,644); activated carbon (US Patent* 4,438,285); apart from the monotiths or fibers (US Patents* 5, 521,139; 5,750,806; 6,365,790 B2; Ind. Eng. Chem. Res., 44, 2005, 6148-6153) etc. are also reported in prior art.
Reaction parameters, types of reactors etc.
The prior art studies referred previously are carried out between a pressure range of 1.5 to 60 bar (excepting in the supercritical CO2 case, Catalysis Today, 93-95 (2004) 439-443, it is 160 bar) and a temperature of 50 to150°C.
The studies have been reported both in batch rectors (autoclave type) or continuous gas liquid type trickle bed or bubble column up flow reactors. US Patent * 6,262,317 B1 describes a multi tubular reactor with 15 numbers of tubes for the hydrogenation study. For the continuous reactors, the gas hourly space velocities (GHSV) are reported from 250 to 12,000 h'1 and the liquid hourly space velocities (LHSV) from 0.05 to 20,000 h"1.
Alkynes in the form of gases or gases absorbed in liquids are reported in prior art.
1,4 butynediol is in the form of aqueous solution up to 50% concentration, excepting in one case (lnd.Eng.Chem.Res.44, 2005, 6148-6153), wherein molten pure 1,4 butynediol (from solid state) hydrogenation is reported in prior art.
The hydrogen gas reported in prior art is generally pure hydrogen; however controlled carbon monoxide addition to hydrogen for better selectivity towards double bond, is also reported in US patents # 5,750,806 and 6,365,730 B*
Catalyst activity
Catalyst activity, expressed in g of alkyne (or particularly 1,4 butynediol, as the case may be) reacted per day per gram of (total) metal contents in the catalyst is calculated typically for the following cases mentioned in prior art:
- For US Patent # 7,288,686 B1, in Exampte 2, WHSV values of 4, 3, 4, 6.1 g hydrocarbon/ (hour-g catalyst) are mentioned. For the catalyst composition of 0.2% Pd, 0.11% Ag, 0.27% Zn and 1.42% Bi, the total metal content of the catalyst is 2%, the balance being alumina. Hence catalyst activity values of 200, 150, 200, 305 g hydrocarbon/ (hour- g metal content), can be calculated for 36 g total catalyst used, which works out equivalent to 4800, 3600, 4800, 7320 g hydrocarbon reacted/(day-g metal).
- For Canadian Patent # 1,090,829 in Example 1, an activity of 3962 g butynediol reacted/(day-g metal), can be calculated for the Pd/ 'catalyst with Pb (as lead acetate), continuous addition in an autoclave.
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- For US Patent # 6,262,317 Bt, an activity in the range of 130 to 260 g butynediol/(day-g metal) can be calculated for the ranges Ni/Mo on AI2O3 catalyst. Particularly for Example 5 in a tube reactor, an activity of 75 g butanediol per hour i.e. 108 g butynediol reacted per hour, can be calculated for 20 g Raney Ni/Mo catalyst used, which works out equivalent to 130 g butynediol reacted/ (day-g metal).
- For US Patent # 6,469,221 Bi, an activity in the range of 80 to 260 g butynediol reacted/ (day-g metal) can be calculated for the 1% Pt/ CaC03 catalyst. Particularly for example 15 in a single tube reactor for 10 cc/h of 20% butynediol solution hydrogenated with 30 g of 1% Pt/CaCOs catalyst, the catalyst activity works out to 160 g butynediol reacted/ (day-g metal).
Object of the Invention
The object of the present invention is to provide an efficient, commercially attractive process for the preparation of aikenes, particularly 1, 4 butenediol with high selectivity and activity per unit of metal contents, by hydrogenating the corresponding alkynes, particularly pure or technical grade 1,4 butynediol, under low pressure and temperature, in the absence of any additives for improving selectivity (e.g. CO), by a commercially available suitably supported catalyst containing a single metal component, prepared in any conventional manner and achieving a longer catalyst life.
Summary of the Invention
The object of the present invention is achieved by a process for the hydrogenation of alkynes, particularly technical grade 1,4 butynediol, in a reactor, in the presence of a standard commercial catalyst prepared in any conventional manner, working under hydrogenation pressure from 1 to 20 bar, at a temperature range of 15 to 250°C, under hydrogen pressure from 1 to 20 bar, under space velocity ranging from: GHSV 1 to 10,000 h"\ and LHSV 0.001 to 10 h'1.
In one embodiment of the present invention, the process is preferably carried out using pure or technical grade 1,4 butynediol- synthesized by various alternate routes correspondingly , from acetylene and aqueous formaldehyde. The strength of butynediol solution is 20 to 60%, preferably aqueous solution.
In another embodiment of the invention, the hydrogen gas is in pure form and in particular, carbon monoxide or any other compound is not periodically added to the same for controlling the selectivity.
In a preferred embodiment of the invention, the hydrogenation reaction is carried out in a continuous single tube bubble column up flow reactor.
In another embodiment of the invention, the hydrogenation catalysts are capable of hydrogenating triple to double and subsequently to single bond compounds, which may contain very low amount of a single active metal, chosen from palladium, nickel, molybdenum, copper or platinum. The active metal content may vary from 0.0001 to 1%, preferably from 0.0005 to 0.01%. The catalyst support can be selected from alumina, alumino silicates, silica gel or activated carbons. More efficient utilization of
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the active metal results in high activity per unit of metal contents , at the same time giving very high selectivity. In another embodiment of the invention, typical physical properties of the catalyst being: the surface area between 3 to 300 nr/g, preferably 5 to 10 m2/g; the pore volume between 0.05 to 0.6 cc/g, preferably 0.15 to 0.50 cc/g; the side crushing strength between 2 to 20 kg, preferably 5 to 15 kg. The most preferred catalyst being palladium supported on alumina in a wide range of palladium contents offered within the range of these physical properties. Catalysts of. this type are commercially available under the various grades as follows:
M/s Arora Matthey, India: 50 B; Degussa, Japan: E/221, E/252; Johnson Matthey, UK: R-48, JM 308/1; Met-Pro, USA; Sud Chemie AG, Germany: G-68,G-68C, G83, G-83C; UCI, USA (now Sud Chemie, USA): G68E; UCIL, India (now Sud Chemie, India): 995X, 996X, 1021-X.WN-333.
In another embodiment of the invention, the process is carried out under hydrogen pressures from 5 to 15 bar.
In another embodiment of the invention, the process is carried out at a temperature in the range of 50-150°C.
In another embodiment of the invention, the gas hourly space velocity (GHSV) for the process is in the range of 10 to 1000 h-1.
In another embodiment of the invention, the liquid hourly space velocity (LHSV) for the process is in the range of 0.01 to 1 h-1.
In further embodiment of this invention, no special activation method is required for the catalyst before hand.
In another embodiment of the invention, the catalyst is run consecutively for more than 5000 hours.
In another embodiment of the invention, the process is scaled up 1:10 times in a similar single tube reactor, without adversely affecting the selectivity of alkenes.
Detailed Description
Hydrogenation reactor for the present study consisted of a standard stainless steel continuous single tube reactor, with an outside jacket arrangement for heat removal. Gas & liquid were introduced at the bottom of the reactor in co-current up flow manner. At the reactor outlet from the top, the two phases were separated in a gas-liquid separator. The hydrogenation runs were carried out once through for the liquid as well as gas. In an industrial set up, gas recycle arrangement after the gas-liquid separator is easily possible.
The reactor was packed with catalysts containing Pd in various proportions
from amongst the commercially available catalysts of various grades from different suppliers mentioned earlier. Pure industrial hydrogen gas as such was used. Carbon monoxide (CO) or any other components were not added at any time to the hydrogen to influence on the hydrogenation process selectivity. Pure 1,4 butynediol 'Afdrich' make was used. Technical grade 1,4 butynediol was obtained by synthesizing acetylene and aqueous formaldehyde under different catalysts/different conditions at Hindustan Organic Chemicals Ltd., Rasayani, Maharashtra, India.
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Analyses of the reactant as well as products were carried out by gas chromatography.
Runs were carried out starting with 0.1% Pd/A12O3 catalyst (a). To get a comparison of the selectivity improvement, zinc as the additional metal component was used in two ways. Firstly (b), impregnation with zinc and reduction of the 0.1% Pd/A12O3 catalyst were done 'in-situ'. In second method (c), continuous addition of zinc was made to butynediol solution in a similar manner as described by Hart for lead acetate addition (Canadian Patent # 1,090,829). This is illustrated by Example 1. It shows that marginal improvent in selectivity is achieved by additional component, that too when it is present in the feed solution and not on the catalyst surface, as compared to the base case when additional metal is not introduced.
Further investigations were carried out without any additional metal, other than the palladium already present in the available Pd/A12O3 catalyst. These are described from Example 2 onwards.
The catalyst activity for various Pd/A12O3 catalysts is described in Example 2, as a function of LHSV for constant value of GHSV. Technical grade 1,4 butynediol produced under different catalysts (typically Catalyst #1 and Catalyst #2) at Hindustan Organic Chemicals Limited, Rasayani, Maharashtra, India, was employed for the study. The catalyst activity expressed per unit mass of the catalyst shows inconsistency, however the activity based on unit mass of the active metal is found to increase with lower active metal containing (typically palladium) catalysts, under all conditions. Hence this was selected as a proper basts for all further comparisons. Example 3 showing the variation of GHSV with LHSV confirms that the reaction is influenced by mass transfer effects.
Further study, illustrated by Examples 4 to 8 focuses on the selectivity for 1,4 butenediol.
It can be seen from Example 4 that there is a threshold catalytic activity, beyond which the selectivity to 1,4 butenediol is adversely affected. The lower the active metal (palladium) contents of the catalyst, the higher the threshold catalytic activity. tn other words, the lower active metal contents can tolerate higher activity better' for the process, while retaining its selectivity towards 1,4 butenediol.
As per the specifications / requirements of pure 1,4 butenediol finished product, unreacted 1,4 butynediol has to be negligible in the same. This means that the hydrogenation process must proceed towards complete conversion of 1,4 butynediol. It also requires 1,4 butanedbl to be as low as possible (1-2%), Example 5 illustrates that with lowering of active metal (palladium) contents of the catalysts, selectivity towards 1,4 butenediol (desirable) improves significantly at complete conversions of 1,4 butynediol, by suppressing the formation of 1,4 butanedbl (undesirable). Example 6 further reaffirms this selectivity trend, where pure 1,4 butynediol is used. Thus the process selectivity improves with lower active metal contents for 1,4 butynediol prepared by various techniques.
It is also industrially required that the process should not only give good selectivity at complete conversions, but under over hydrogenation conditions, wherein the amount of 1,4 butynediol is absent. This is verified by Example 7 wherein pure 1,4 butenediol product in aqueous solution was introduced as feed, hydrogenated and the outlet product showed consistency in the assay content of 1,4 butenediol, under similar
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hydrogenation process conditions as for 1,4 butynedioi. This was further established in the 1:10 scaled up version of the bubble column up flow reactor by Example 8.
The present invention is described below by way of examples. However, the following examples are illustrative and should not be construed as limiting the scope of the invention. All the concentrations are expressed in percentage by weight, unless otherwise stated.
Example 1
(Comparative Example)
(a) Continuous hydrogenation with palladium on alumina (Pd/A12O3)
catalyst
The continuous single tube bubble column reactor described earlier, was packed with 0.1% of Pd/ Pd/A12O3 catalyst. Continuous Hydrogenation using the above catalyst for technical grade 35% butynedioi solution (prepared from aqueous formaldehyde and acetylene under different catalysts of butynedioi synthesis at Hindustan Organic Chemicals Limited, Rasayani, Maharashtra, India) was carried out in the same, under the foliowing experimental conditions/parameters:
Pressure = 10 bar
Temperature = 110°C
The gas hourly space velocfty (GHSV) was maintained at about 310 h-1 and the liquid hourly space velocity (LHSV) kept at about 0.075 h-11.
Catalyst activity obtained at full conversion of butynedioi was 504 g butynedioi/ (day- kg catalyst).
(b) Zinc surface treatment 'in situ 'for the Pd/A12O3 catalyst
About 1300 cc DM water containing 10 to 20% zinc acetate was charged to the feed tank. This was introduced into the hydrogenation reactor described in part (a), containing 0.1% Pd/A12O3 catalyst under 12 bar hydrogen pressure and at ambient (30°C) temperature. A liquid hourly space velocity (LHSV) of 0.15 h-1 was maintained for 24 hrs. The liquid feed was then stopped. The reactor was kept at ambient temperature and 12 barH 2pressure, subsequently for 65 hrs. Gas was then introduced at a gas hourly space velocity (GHSV) of 310 h, maintained by hydrogen bubbling for 24 hrs at 107°C to reduce the zinc acetate to zinc. The outlet gas was vented through a water seat Afterwards DM water wash was given under the same conditions as above so that total reactor holdup was displaced once. The catalyst was then ready for reaction.
Continuous Hydrogenation using the above pre-treated catalyst for technical grade 35% butynedioi solution, as described and under the same experimental conditions/parameters as mentioned in part (a) was carried out in the reactor.
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(c) Continuous line addition to butynediol solution with Pd/A12O3 catalyst
The hydrogenation reactor containing 0.1% Pd/A12O3 catalyst as described in part (a) was used for this study. Zinc (60- to 500 ppm) was introduced in the form of zinc acetate dihydrate by addition to the technical grade 35% butynediol solution , as described in part (a).
Continuous Hydrogenation using the zinc containing 1,4 butynediol solution was carried out in the reactor, under the same experimental conditions/parameters as described in part (a).
The selectivities for the three cases viz. (a) catalyst as such, (b) surface treatment on the catalyst with zinc and (c) zinc introduced in the liquid feed itself, are tabulated in Table 1.
Table 1

Example 2
The same continuous single tube bubble column up flow reactor as referred to in Example 1, was used for hydrogenation studies of technical grade aqueous butynediol solutions prepared from aqueous formaldehyde and acetylene under two different catalysts (Catalysts #1 and #2 respectively) of butynediol synthesis at Hindustan Organic Chemicals Limited, Rasayani, Maharashtra, India, under the same pressure and temperature conditions as mentioned in Example 1, except that the hydrogenation reactor was packed with standard industrial Pd/A12O3 catalysts containing palladium contents in varying amounts. The runs were carried out under varying liquid hourly space velocities (LHSV), keeping Gas hourly space velocity (GHSV) constant. The results are tabulated in Table 2. The catalyst activity in part (A) is expressed as grams of butynediol reacted per day- per kilogram of the catalyst. However, to get a better comparison of the activity, the same is also expressed in terms of grams of palladium contents in the catalyst in part (B).
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Table 2 (i) Runs with Butynediol Synthesized under Catalyst #1

(A)


(ii) Runs with Butynediol Synthesized under Catalyst #2



Example 3
The same continuous single tube bubble column up flow reactor as referred to in Example 1 was used for hydrogenation of j/arious technical grade aqueous butynediol solutions with standard industrial Pd/A12O3catalysts containing palladium contents in varying amounts, as referred to in Example 2 and was operated at the same temperature and pressure conditions as mentioned in Example 1, except that the runs were carried out under varying GHSV's, at constant LHSV's. The results are tabulated in Table 3. The catalyst activity is expressed here as grams of butynediol reacted per day- per gram of palladium contents in the catalyst.
Table 3



Example 4
The same continuous single tube bubble column up flow reactor as referred to in Example 1 was used for hydrogenation of various technical grade aqueous butynediol solutions with standard industrial Pd/AfeOs catalysts containing palladium contents in varying amounts, under the same range of GHSV and LHSV as referred to in example 2 and 3, and was operated at the same temperature and pressure conditions as mentioned in Example 1. The results are tabulated in Table 4. The catalyst activity, as in Example 3, is expressed as grams of butynediol reacted per day- per gram of palladium contents in the catalyst.
Table 4
(i) Runs with Butynediol Synthesized under Catalyst #1



• Threshold catalyst activity.

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Runs with Butynediol Synthesized under Catalyst #2



• Threshold catalyst activity.
@ Threshold catalyst activity still higher than this activity range.
Examples
The same continuous single tube bubble column up flow reactor as referred to in Example 1 was used for hydrogenation of various technical grade aqueous butynediol solutions with standard industrial Pd/A12O3 catalysts containing palladium contents in varying amounts, under the same range of GHSV and LHSV as referred to in example 2 and 3, and was operated at the same temperature and pressure conditions as mentioned in Example 1. Hydrogenation in this case, was carried out such that complete conversion of 1,4 butynedid is achieved, Selectivrties for the desired product (1,4 butenedioi) and the undesired product (1,4 butanediol) are expressed. The results are tabulated in Table 5.
Tables
(I) Runs with Butynediol Synthesized under Catalyst #1

S*lo Pd contents (%wfa)'m catalyst % Selectivity to butenedioi % Selectivity to butanediol
1. 0.1 55 29
2 0.018 60 15
3 0.0)54 62 14
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(ii) Runs with Butynediol Synthesized under Catalyst #2


Example 6
The same continuous single tube bubble column up flow reactor as referred to in Example 1 was used for hydrogenation studies of pure Butynediol ('Aldrich' make) dissolved in demineralized water to make a 35% solution and was operated at the same temperature and pressure conditions as mentioned in Example 1. The hydrogenation reactor was packed with standard industrial Pd/A12O3 catalysts containing 0.002% Pd contents, and was operated under the same range of GHSV and LHSV as mentioned in Examples 2 and 3. Hydrogenation was carried out just near complete conversion of butynediol. The catalyst activity achieved was 13,100 of butynediol/day-g palladium. Selectivities for the desired product (1,4 butenediol) and the undesired product (1,4 butanediol) are expressed. The results are tabulated in Table 6.
Table 6

Various runs on the 0.002% Pd/A12O3 catalyst as illustrated by Examples 2,3,4,5 and 6 were carried out for a total duration of more than 5000 hours. The catalyst activity showed consistency during this period.
Example 7
The same continuous single tube bubble column up flow reactor as referred to in Example 1 was used for hydrogenation studies of industrially available pure 1,4 butenediol, dissolved in demineralized water to make a 35% solution and was operated at the same temperature and pressure conditions as mentioned in Example 1. The hydrogenation reactor was packed with standard industrial Pd/A12O3catalysts containing 0.002% Pd contents (as in example 6), and was operated under the same range of GHSV and LHSV as mentioned in Examples 2 and 3. The results are tabulated in Table 7.
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Table 7


Example 8
Hydrogenation study for over hydrogenation of pure butenediol, as illustrated in Example 7, was repeated in a 1:10 scaled up version of the continuous single tube bubble column up flow reactor, as described in Example 1, and maintained at the same temperature and pressure conditions in Example 1 and operated under the same range of GHSV and LHSV as mentioned in Examples 2 and 3. The hydrogenation reactor was packed with standard industrial Pd/A12O3 catalysts containing 0.002% pd contents (as in Examples 6 and 7). The results are tabulated in Table 8.
Table 8

Advantages of the Invention
1. The process, which uses very tow palladium contents and no other additional
metal and which does not require any additional compound along with
hydrogen for achieving selectivity of alkynes to alkenes, as illustrated for
1,4 butynediol to 1,4 butenediol hydrogenation.
2. The process can utilize 1,4 butynediol right from highly pure grade to any technical grade, which may be synthesized by various alternative processes using different catalysts, from the reaction of formaldehyde and acetylene.
3. Very high selectivity of 1, 4 butenediol is obtained even with the complete conversion of 1, 4 butynediol by the present process and its good over-hydrogenation capability, with reproducible results even at higher scale up
ratios.
4. The influence of mass transfer on the present process can be advantageously
used for achieving high activity, by choosing a right combination of GHSV and
LHSV, which will result in more throughputs.
All the above aspects make the process commercially very attractive, as well as easier for operation at higher scale up ratios.
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We claim:
1. An improved process for the selective hydrogenation of alkynes to alkenes, using substantially lower content of a single metal suitably supported catalyst, under lower hydrogen pressure: from 1 to 20 bar, at a lower temperature: between .15 to 250*0, with GHSV in the range of 1 to 10, 000 h'\ LHSV in the range of 0.001 to 10 h'1, exhibiting high catalyst activity per unit of metal content and longer catalyst life.
2. The process as claimed in claim 1, which is further, carried out in continuous single tube bubble column up flow reactors, with pure hydrogen, without any selectivity enhancers.
3. The process as claimed in claims 1 and 2, wherein said selective hydrogenation of alkynes to alkenes further comprises of selective hydrogenation of 1,4 butynediol to 1,4 butenedto!.
4. The process as claimed in claim 3, wherein said 1,4 butynediol further comprises of pure 1,4 butynediol or technical grade 1,4 butynediol synthesized from aqueous formaldehyde and acetylene, using different catalysts by any suitable route.
5. Tihe process as cfarrned (h cfaims 1 and 2, wherein sard sfngte metat surtably supported catalyst contains a single metal in the range of 0.0001 to 1%.
6. The process as claimed in claim 5, wherein said catalyst further comprises of palladium metal on alumina support in the range of 0.0005 to 0.01%.
7. The process as claimed in claims 1 to 5, wherein said catalyst surface area is in the range of 3 to 300 m2 /g, preferably 5 to 10 m2 /g.
8. The process as claimed in claims 1 to 5, wherein said catalyst pore volume is in the range of 0.05 to 0.60 cc/g, preferably 0.15 to 0.50 kg.
9. The process as claimed in claim 1 to 5, wherein the side crushing strength of said catalyst varies from 2 to 20 kg, preferably 5 to 50 kg.
10. The process as claimed in claims 1 and 2, wherein the hydrogen pressure is preferably in the range of 5 to 15 bar.
11.The process as claimed in claims 1 and 2, wherein the temperature is preferably in the range of 50 to 150° C.
12. The process as claimed in claims 1 and 2, wherein the GHSV is preferably in the range of 10 to 1,000 h"1.
13.The process as claimed in claims 1 and 2, wherein the LHSV is preferably in the range of 0.01 to 1 h"1.
14. The process as claimed fn claims 1 to 13, wherein said catalyst activity is in the range of 10 to 10,00,000 g alkyne reacted/ (day-g of metal contents in the catalyst).
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15. The process as claimed in claims 1 to 14, wherein said catalyst is run for a long duration exceeding 5,000 hrs. ■
16.The process as claimed in claims 1 to 15, wherein the over hydrogenation of alkenes to atkanes is negligible.
17. The process as claimed in claims 1 to 16, which can be scaled up to a higher scale by at least a scale up ratio of 1:10 with the help of commercially available catalysts, in continuous single tube or multitubular reactor (s), without adversely affecting the selectivity towards alkenes substantially as herein described with reference to Examples 1 to 8 in the specification.
Dated this day of 2008

(ARVIND SHRIRAM DIDOLKAR) Chairman & Managing Director
For and on behalf of M/s Hindustan Organic Chemicals Limited
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Documents:

2215-MUM-2008-ABSTRACT(GRANTED)-(9-12-2011).pdf

2215-mum-2008-abstract.doc

2215-mum-2008-abstract.pdf

2215-MUM-2008-ANNEXTURE(19-8-2011).pdf

2215-MUM-2008-ANNEXTURE(20-10-2011).pdf

2215-MUM-2008-ANNEXURE A(20-10-2011).pdf

2215-MUM-2008-CANCELLED PAGES(20-10-2011).pdf

2215-MUM-2008-CLAIMS(AMENDED)-(20-10-2011).pdf

2215-MUM-2008-CLAIMS(GRANTED)-(9-12-2011).pdf

2215-MUM-2008-CLAIMS(MARKED COPY)-(20-10-2011).pdf

2215-mum-2008-claims.doc

2215-mum-2008-claims.pdf

2215-MUM-2008-CORRESPONDENCE(15-4-2011).pdf

2215-MUM-2008-CORRESPONDENCE(19-8-2011).pdf

2215-MUM-2008-CORRESPONDENCE(IPO)-(9-12-2011).pdf

2215-mum-2008-description(complete).doc

2215-mum-2008-description(complete).pdf

2215-MUM-2008-DESCRIPTION(GRANTED)-(9-12-2011).pdf

2215-mum-2008-form 1.pdf

2215-mum-2008-form 18.pdf

2215-MUM-2008-FORM 2(GRANTED)-(9-12-2011).pdf

2215-MUM-2008-FORM 2(TITLE PAGE)-(GRANTED)-(9-12-2011).pdf

2215-mum-2008-form 2(title page).pdf

2215-mum-2008-form 2.doc

2215-mum-2008-form 2.pdf

2215-mum-2008-form 3.pdf

2215-mum-2008-form 5.pdf

2215-mum-2008-form 9(15-10-2008).pdf

2215-MUM-2008-OTHER DOCUMENT(19-8-2011).pdf

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2215-MUM-2008-REPLY TO HEARING(20-10-2011).pdf

FORM9.TIF


Patent Number 250127
Indian Patent Application Number 2215/MUM/2008
PG Journal Number 49/2011
Publication Date 09-Dec-2011
Grant Date 09-Dec-2011
Date of Filing 15-Oct-2008
Name of Patentee HINDUSTAN ORGANIC CHEMICALS LIMITED
Applicant Address RASAYANI, DIST.RAIGAD.
Inventors:
# Inventor's Name Inventor's Address
1 SATHE AMOD MADHUKAR RASAYANI, DIST.RAIGAD, PIN-410207.
2 SHINDE BAPURAO SIDRAM RASAYANI, DIST.RAIGAD, PIN-410207.
PCT International Classification Number C07B61/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA