Title of Invention	"An improved process for the manufacture of hydrogenated rosin and its esters."
Abstract	This invention provides an improved process for the manufacture of hydrogenated rosin and its esters, using easily preparable, low cost, base metal catalyst such as Raney Nickel, at quite low pressure, using a mixture of hydrogen and an inert gas like nitrogen available commercially at much lower price than pure hydrogen.

Full Text

AN IMPROVED PROCESS FOR THE MANUFACTURE OF HYDROGENATED ROSIN AND ITS ESTERS This invention perticularly relates to an improved process for the manufacture of Hydrogenated Rosin and its Esters, using easily preparable, low cost, base metal caitalyst such as Raney Nickel, at quite low pressure, using a mixture of hydrogen and an inert gas like nitrogen available commercially at much lower price than pure hydrogen. The catalyst used is recovered through a sedimentation centrifuge instead of by settling forlong hours. The catalyst can be recycled a number of times and finally reused for making fresh catalyst. Rosin consists of mainly abietic type acids, small amount of pi-maric type acids in addition to little amount of non-acidic components such as rosin acid esters, anhydrides, aldehydes, hydrocarbons, unsaponifiable matter and fatty acids. It is sensitive to atmospheric oxidation due to the presence of conjugated double bonds in the molecules of abietic type acids. The pimaric type acids present are relatively inert. The arial oxidation causes rosin to darken embrittle and less soluble in low solvency solvents thereby making it of lower value for most uses.One of the most satisfactory methods of making it resistant to air oxidation and getting a product of light colour is by hydrgenation. The hydrogenated products prepared by the process of the invention are light in colour, highly resistant to atmospheric oxidation and find application in highly specialized adhesives, surgical tapes, synthetic rubber, chewing gum, high grade paper etc. The esters of hydrogenated rosin are equally important and are rather more suited for speciality applications where resistance to air oxidation and discolouration by heat are required. Such applications are pressure sensitive adhesives made from synthetic rubber, chewing gum and hot melt applied coatings. Some of the common esters in demand are those of glycerol, pentaerythritol, methanol etc. The hydrogenation reactions are presented in Figs I and II. Hydrogenation decreases the two double bonds present in the rosin acids from 74 to 3% and increases the dihydroacids from 1 to 75%, hence'an overall conversion of former to the hydrogenated rosin. Further hydrogenation completely eliminates the double bonds of rosin acids thereby producing to the extent of 1-14% dihydro acids and 66-8 0% tetrahydroacids to give highly or perhydrogenated rosin as shown in Table I. TABLE - I Double bonds present in hydrogenated Rosin Acids (Table Removed) Hydrogenation has been carried out by using different types of catalysts with or without the presence of solvents. Among the catalysts reported are: 1. Noble metal catalysts, such as Pt02 or Pd/c, Rh/c, Ru/c used individally or in combination. 2. Base metal catalysts, such as Ni.Mn.Si alloy, Ni-Si al 1 oy or Raney Nickel. Most of the catalysts reported have been used for hydrogenating rosin as well as its esters. Noble metal catalysts E.D. schulz (Hercules Power Co.), U.S. Pat. 2,346, 793, (1944) has reported that the reaction can be accomplised at atmospheric pressure at 20-30°C, using Pt02 as catalyst, in presence of acetic acid and H3Po4 but the catalyst concentration reported is as high as 30-75%, which is very high, A.L. Grasebrook (Hercules Power Co.), U.S. Pat.2, 776,276, Jan. 1957, carried out the reaction at 3000-5000 Psi, using 5% Pd/c at a concentration of 2%, eleminating the use of solvent. I.I. Bradysher and E.B. Smirnova, Gidrolizn, i, Lesokhim prom. 19(4), 4-6, 1966 (Russ), has reported an optimum pressure of 50 kg/cm2 at a palladium concentration of 0.3% which corresponds to 6% concentration of 5% Pd/c in presence of solvent like hydrogen saturated gasoline. Here again the catalyst concentration as well as pressure are high and the saturation obtained is to the removal of one double bond only. Zhao, Shoupu; et.al. Linchan Huaxve yu Gongye 1981,1(1), 1-12 (ch) have reported hydrogenation of rosin to a saturation of one double bond only on a continuous scale in a fixed bad reactor using 5% Pd/c as catalyst at 220-250°C and 130 kg/cm2 pressure. Here again the catalyst cncentration and pressure are high and hydrogenation partial only. Saving kh V.I., et.al, Gidroliz, Lesokhim, Promst 1992(3), 19-20(Russ) have used palladium containing catalyst 1KT3-31 for hydrogenation of Rosin at 13 0°C and 0.5-1.5 MPa H2 pressure But the product obtained still contained Chinese Academy of forest science, Lin yeh K'oH such, 1979, 15(4), 269-75(ch), have also reported hydrogenation of rosin in presence of 0.01 % catalyst (5% Pd/c) at 270°C, but the hydrogen pressure used was quite high, around 179 kg/cm2, corresponding to 100kg/cm2, initial cold pressure at 3 0°C. Recently Zhang, yunming et.al. in their patent Faming Zhuanli shenging Gongkai shuoming shu CN 1,097,448 (cl.C09Fl/04) 18 Jan, 1995 have reported the use of Palladium 0.05 % /c as catalyst. They obtained dihydrogenated rosin at 4-6 MPa at 150-170°C and tetrahydrogenated rosin at 7-10 MPa and 175-2 00°C. On the whole the concentration of 5% Pd/c varied from 0.01% to 6% at corresponding pressures of 179 kg/cm2 and 50 kg/cm2 respectively, whereas the concentration of Pt02 used at atmospheric pressure was as high as 30-75%. In case of noble metal catalysts, the basic cost of catalysts is quite high. Further they are once used only and need recovery of the metal every time for repreparation of the catalyst for reuse. This involve cost due to Ipsses, equipment, use of chemicals and labour etc. for repreparation. The pressures required are quite high e.g. 179 kg/cm2 at minimum of 0.01% catalyst concentration and 50 kg/cm2 at a concentration of as high as 6% of 5% Pd/c. Thus the overall pressures required are quite high and catalysts being cost prohibitive even after recovery and reuse. Base metal catalysts To reduce the cost of production, base metal catalysts such as Nickel supported on Si/Al etc. or unsupported like Raney Nickel have also been used with or without the use of solvents. I.W. Humphery (Hercules power co. ) U.S.Pat 2,113,808 (1938) reported the use of base metal catalyst such as Ni at 2000-15000 Psi at 125 -225°C.But it affected only 50% saturation of unsaturated bonds. Rolling J.B. (Herecules Power co) U.S. Pat 2, 155,036, April 1939, used Ni-si alloy as catalyst, but the pressure required was again high 2500-5000 Psi at 18 0-22 0°C. J.C. Funderbuck, U.S.Pat. 2,739,947, March 1956 incorporated Mn&C in the Ni-Si alloy catalyst to improve its strength, but the pressure required for hydrogenation was 5000 Psi at 525°;R.J. Byrket (Hercules power Co.) U.S. Pat. 2,094,117,Sept.28,1937 used Ni-Al alloy.as catalyst for hydrogenating Methyl or Glyceryl abietate at super atmospheric pressure and high temperature. Polish Pat. 46,722 of 1966 reported the use of Raney Nickel type of catalyst prepared from Nickel formate, but the most favourable conditions reported for hydrogenation are 210-300°C at 250 kg/cm2- with a catalyst concentration of 0.25% Nickel. They recovered the catalyst for reuse by sedimentation at 18 0°C for several hours, but the pressure required for hydrogenation was very high. It is thus clear that even in case of base metal catalysts, whether in the form of supported and shaped catalysts or in the form of Raney Nickel, with or without the use of solvents, the pressure required for hydrogenation is around 200 kg/cm2, which is quite high. This warrants the use of high pressure specialised equipment which is not made in India and has to be imported involving high initial cost. Secondly it require highly trained personnel for its operation and maintenance. Even the hydrogen gas used in all the processes reported is pure having more than 99.95% purity and-'expensive. All this make the process expensive. The main objective of the present invention is to provide an improved process for the manufacture of hydrogenated rosin and its esters, without the use of any solvent, using cheap, easily preparable Raney Nickel type catalyst which could be recycled as such a number of times without repreparation. Another objective of the present invention is to reduce the reaction pressure to a minimum so that the reactor of commercial size could be made in India. Still another objective of the present invention is to use a mixture of hydrogen and an inert gas like nitrogen available commercially from an ammonia cracker at a much cheaper rate than pure hydrogen or anyother such combination. Yet another objective of the present invention is to recover the catalyst through sedimentation centrifuge immediately after the reaction is over so as to produce product of lighter colour instead of allowing it to settle for several hours as is done conventionally. Accordingly the present invention provides an improved process for the manufacture of hydrogenated rosin and its esters which comprises: reacting rosin/rosin ester with a mixture of hydrogen and an inert gas, in presence of a catalyst such as herein described, at a concentration in the range of 0.1 to 10.0%, under a pressure in the range of 10 to 160 kg/cm2, at a temperature in the range of 120 to 300°C, for a period in the range of 1 to 12 hrs, separating the catalyst and recovering the products by conventional method, the said process is characterized in reacting rosin/rosin ester with mixture of hydrogen and inert gas in presence of catalyst, preferably nickel catalyst at a pressure ranging 10-160 kg/cm2. In an embodiment of the present invention an inert gas used may be such as N2, Ar, He, Kr. And the ratio of H2 and inert gas used may be in the range of 1 : 0 to 1: 2. In another embodiment of the present invention the catalyst used may be such as nickel obtained by thermal decomposition of nickel formate or a combination of nickel and copper obtained by thermal decomposition of their organic salts. After the reaction the catalyst may be separated by filtration , sedimentation or through sedimentation centrifuge. The catalyst thus recovered can be recycled as such a number of times before it looses its activity. It can then be converted back to nickel formate by usual method. The extent of hydrogenation depends upon the time duration (1 to 12 hours) given for the reaction. The product obtained is lighter in colour when the catalyst is recovered for recycling through sedimentation centrifuge. The catalyst on loosing its activity after recycling a number of times (15 to 20) , can be converted back to form Nickel formate for reuse. The invention is described further with reference to the examples given below. These examples should not be construed as to restrict the scope of the invention. Advantages of the process: The present invention uses low cost, easily preparable, base metal catalyst such as Raney Nickel. In this the reaction pressure has been brought down to only a fraction of that reported in litrature.lt does not involve the use of any solvent. Further it makes use of a mixture of hydrogen and an innert gas such as nitrogen available from a cheap source like ammonia cracker, instead of pure hydrogen which is costly. With these the total plant cost goes down and a plant having capacity of even one tonne/batch can be made in India. The catalyst is recovered through sedimentation centrifuge, giving a product lighter in colour, compared to recovery through settling for long hours, which is energy and time consuming. The catalyst thus recovered can be recycled a number of times,(15 to 20) till it looses its activity. It is then reconverted for preparation of fresh catalyst. The process can produce hydrogenated and highly hydrogenated products by varying reaction time only. The process is equally good for hydrogenating esters of rosin. The , following examples are given by way of illustrations an. should not construed to limit the scope of the present invention EXAMPLES:- A. HYDROGENATED ROSIN EXAMPLE 1 100 g Rosin and 3 g Nickel formate (Ni=0.953 g) charged in glass liner fitted in 4 litre rotating type high pressure autoclave. The autoclave was closed, purged and charged with hydrogen gas upto 90 kg/cm2at room temperature. The temperature was then raised to 250°C, when the pressure rose to 160 kg/cm2' After 6 hours reaction time the product was found matching with the ultraviolet spectrum and other properties of hydrogenated rosin. The yield obtained was more than 98%. EXAMPLE 2 100 g Rosin and 3 g Nickel formate (Ni=0.953 g) charged in glass liner fitted in 4 litre rotating type high pressure autoclave. The autoclave was closed, purged and charged with hydrogen gas upto 90 kg/cm2 at room temperature. The temperature was then raised to 250oC- when the pressure rose to 160 kg/cm2' After 8 hours reaction time the product was found matching with the ultraviolet spectrum and other properties of highly or perhydrogenated rosin.The yield obtained was more than 98%. EXAMPLE 3 100 g Rosin and 9 g Nickel formate (Ni=2.859 g) charged in glass liner fitted in 4 litre rotating type high pressure autoclave. The autoclave was closed purged and charged with hydrogen gas upto 15 kg/cm2 at room temperature. The temperature was then raised to 250oC' when the pressure rose to 25 kg/cm2' After 4 hours reaction time, the product was found matching with the ultraviolet spectrum & other properties of hydrogenated rosin. The yield obtained was more than 98%. EXAMPLE 4 100 g Rosin and 9 g Nickel formate (Ni=2.859 g) charged in glass liner fitted in 4 litre rotating type high pressure autoclave. The autoclave was closed, purged and charged with hydrogen gas upto 15 kg/cm2 at room temperature. The temperature was then raised to 250°°' when the pressure rose to 25 kg/cm2. After 6 hours reaction time, the product was found matching with the ultraviolet spectrum & other properties of highly or perhydrogenated rosin. The yield obtained was more than 98%. BATCH PROCESS WITH CONTINUOUS FLOW OF GAS EXAMPLE 5 In a 25 litres high pressure, stationary, verticle cylindrical autoclave, was placed a stainless steel liner of 19 litres capacity, charged with nickel rosin catalyst containing 300 g Nickel, alongwith extra rosin to make a total of 10 kg rosin. The nickel rosin catalyst was prepared by heating 1500 grams rosin with 345 grams Nickel formate at 220°C for 30 minutes in a 5 litres S.S. reactor fitted with stirrer and gas feed tube for continuous flow of innert gas like nitrogen. The catalyst thus prepared was charged in the autoclave liner. The autoclave was fitted with a gase sparger, turbine blade stirrer, thermometer pocket, gas inlet and outlet device for drawin samples. The autoclave was closed, purged with nitrogen gas. Inside temperature was continuously raised. When it reached 150°C, stirring and hydrogen gas purging was started. The hydrogen gas pressure in the autoclave was raised to 25 kg/cm2 and maintained throughout the experiment. When the inside temperature reached 250°C, hydrogen feed rate was raised and maintained at 1875 litres/hr at NTP. The experiment was continued for 8 hours under these conditions. Samples were drawn at 6 hours and 8 hours time periods for ultraviolet spectrum analysis etc. Hydrogen flow was then stopped temperature brought down to 150°C, when stirring was also stopped. The■temperature was then further brought down to 100°C. When the autoclave- lid was opened. The sparger and stirrer were removed. The autoclave lid was replaced and blanket of nitrogen atomsphere kept. The temperature inside was raised and kept at 180°C for 8 hours. It was then allowed to cool to 120°C. The liner was taken out and the upper clean layer of catalyst free material was removed from the liner, through a hole provided for the purpose at 10mm above the bottom of the liner. The ultraviolet sprectrum and other properties of the sample drawn at 6 hrs reaction period matched with that of hydrogenated rosin. The ultraviolet spectrum and other properties of the sample drawn at 8 hours reaction -period matched with that of highly or perhydrogenated rosin. The yield obtained was more than 98%. EXAMPLE 6 In a 25 litres high pressure, stationary, verticle cylindrical autoclave, was placed a stainless steel liner of 19 litres capacity, charged with nickel rosin catalyst containing 300g Nickel, along with extra rosin to make a total of 10 kg rosin. The nickel rosin catalyst was prepared by heating 1500 grams rosin with 345 grams Nickel formate at 220°C for 30 minutes in a 5 litres S.S. reactor fitted with stirrer and gas feed tube for continuous flow of innert gas like nitrogen. The catalyst thus prepared was charged in the autoclave liner. The autoclave was fitted with a gas sparger, terbine blade stirrer, thermometer pocket, gas inlet and outlet, device for drawing the samples. The autoclave was closed, purged with nitrogen gas. Inside temperature was continuously raised. When it reached 150°C. Stirring and purging with a mixture of H2 and N2 gases in the ratio of 1:1 by volume smarted. The gas pressure in the autoclave was raised, to 25 kg/cm2 and maintained -houghout the experiment. When the inside temperature reached 2 7 0°C, the feed rate of gas mixture raised and maintained at 2500 litres/hr at NTP. The experiment was continued for 8 hours under these conditions. Samples were drawn at 6 hours and 8 hours time period for ultraviolet spectrum analysis etc. The gas mixture flow was then stopped, temperature brought down to 150°C, when stirring v/as stopped. The temperature was then further brought down to 10 0°C,when the autoclave lid was opened. The sparger and stirrer were removed. The autoclave lid was replaced and blanket of nitrogen atmosphere kept. The temperature inside was raised and kept at 100°C for 8 hours. It was then allowed to cool to 120°C. The liner was taken out and the upper clean layer of catalyst free material was removed from the liner, through a hole provided for the purpose at 10mm above the bottom of the liner. The ultraviolet spectrum and other properties of the sample drawn at 6 hours reaction period matched with that of hydrogenated rosin. The ultraviolet spectrum and other properties of the sample drawn at 8 hours reaction period matched with that of highly or perhydrogenated rosin. The yield obtained was more that 98%. Recycling of the catalyst: EXAMPLE 7 The Nickel rosin catalyst setled at the bottom of the liner in example 6 was reused as such. To this 10 kg rosin was added. The autoclave was fitted with a gas sparger, turbine blade stirrer, thermometer pocket, gas inlet and outlet, device for drawing samples. The autoclave was closed perger with nitrogen gas. Inside temperature was continuously raised. When it reached 150°C, stirring and purging with a mixture of H2 and N2 gases in the ratio of 2:1 by volume started. The gas pressure in the autoclave was raised to 25 kg/cm2 and maintained throughout the experiment. When the inside temperature reached 2 6 0°C, the feed rate of gas mixture raised and maintained at 2500 litres/hr at NTP. The experiment was continued for 8 hours. Under these conditions samples were drawn at 6 hours and 8 hours time period for ultraviolet spectrum analysis etc. The gas mixture flow was then stopped, temperature brought down to 150°C, when stirring was stopped. The temperature was then further brought down to 100°C, when the autoclave lid was opened. The sparger and stirrer were removed. The autoclave lid was replaced and blanket of nitrogen atmosphere kept. The temperature inside was raised and kept at 180°C for 8 hours. It was then allowed to cool to 12 0°C. The liner was taken out and the upper clean layer of catalyst free material was removed from the liner, through a hole provided for the purpose at 10 mm above the bottom of the liner. The ultraviolet spectrum and other properties of the samples drawn at 6 hour reaction period matched with that of hydrogenated rosin. The ultraviolet spectrum and other properties of the sample drawn at 8 hours reaction period matched with that of highly or perhydrogenated rosin. The yield obtained was more than 98%. C. Hydrogenation of Rosin Esters: EXAMPLE 8 lOOg glyceryl ester of rosin and 9g Nickel formate charged in glass liner fitted in 4 litres rotating type high pressure autoclave. The autoclave was closed, purged and charged with hydrogen gas upto 28 kg/cm2 at room temperature. The temperature was then raised to 270°C. when the pressure rose to 50 kg/cnr. After 6 hours reaction time, the product was found matching with the ultraviolet spectrum and other properties of highly hydrogenated glyceryl ester of rosin. The yield obtained was more than 98%. Batch, process with continuous flow of hydrogen gas, using glyceryl ester of rosin. EXAMPLE 9 In a 25 litres high pressure, stationary, verticle cylindrical autoclave was placed a stainless steel liner of 19 litres capacity, charged with nickel in glyceryl ester of rosin catalyst containing 3 00 g nickel metal, along with extra rosin ester to make a total of 10 kg rosin ester. The catalyst was prepared by heating 1500 grams glyceryl ester of rosin with 345 gram Nickel formate at 220°C for 3 0 minutes in a 5 litres S.S. reactor fitted with stirrer and gas feed tube for continuous flow of innert gas like Nitrogen. The catalyst thus prepared was charged in the autoclave liner. The autoclave was fitted with a gas sparger, turbine blade stirrer, thermometer pocket, gas inlet and outlet,- device for drawing samples. The autoclave was closed purged with nitrogen gas. Inside temperature was continuously raised, when it reached 150°C, stirring and purging with the mixture of Hydrogen and nitrogen mixed in the ratio of 3:1 by volume, started. The gas pressure in the autoclave was raised to 50 kg/cm2 and maintained throughout the experiment. When the inside temperature reached 270°C, gas feed rate was raised to 2500 lit/hr at NTP. The experiment was continued for 8 hours under these conditions. Samples were drawn at 6 hours and 8 hours full time period for ultraviolet spectrum analysis etc. The gas mixture flow was then stopped, temperature brought down at 150°C when stirring was stopped. Temperature was then further brought down to 100°C, when the autoclave lid was opened. The sparger and stirrer were removed. The autoclave lid was replaced and blanket of nitrogen atmosphere kept. The temperature inside was raised and kept at 200°C for 8 hours. It was then allowed to cool to 120°C. The liner was taken out and upper clean layer of catalyst free material was removed from ,the liner, through a hole provided for the purpose at 10mm above the bottom of the liner. The ultraviolet spectrum and other properties of the sample drawn at 6 hours reaction period match with that of hydrogenated rosin ester. The ultraviolet spectrum and other properties of the sample drawn at 8 hours reaction period matched with that of highly of perhydrogenated rosin ester. The yield obtained was more than 98%. Recycling the catalyst: EXAMPLE 10 The nickel rosin ester catalyst settled at the bottom of the liner in example 9 was reused as such. To this 10 kg rosin ester was added. The autoclave was fitted with a gas sparger, turbine blade stirrer, thermometer pocket, gas inlet and outlet, device for We Claim: 1. An improved process for the manufacture of hydrogenated rosin and its esters which comprises: reacting rosin/rosin ester with a mixture of hydrogen and an inert gas, in presence of a catalyst such as herein described, at a concentration in the range of 0.1 to 10.0%, under a pressure in the range of 10 to 160 kg/cm2, at a temperature in the range of 120 to 300°C, for a period in the range of 1 to 12 hrs, separating the catalyst and recovering the products by conventional method, the said process is characterized in reacting rosin/rosin ester with mixture of hydrogen and inert gas in presence of catalyst, preferably nickel catalyst at a pressure ranging 10-160 kg/cm2. 2. A process as claimed in claim 1, wherein the inert gas used is such as N2, Ar, He, Kr and the ratio of H2 & inert gas used in the range of 1 : 01 to 1 :2. 3. An improved process as claimed in claim 1 and 2 wherein the catalyst used is nickel obtained by thermal decomposition of nickel formate or a combination of nickel and copper obtained by thermal decomposition of their organic salts. 4. An improved process for the manufacture of hydrogenated rosin and its esters substantially as herein described with reference to the examples.

Documents:

2443-del-1997-abstract.pdf

2443-del-1997-claims.pdf

2443-del-1997-complete specification (granted).pdf

2443-del-1997-correspondence-others.pdf

2443-del-1997-correspondence-po.pdf

2443-DEL-1997-Description (Complete).pdf

2443-del-1997-drawings.pdf

2443-del-1997-form-1.pdf

2443-del-1997-form-19.pdf

2443-del-1997-form-2.pdf

2443-del-1997-form-3.pdf