CLIAMS: ,TagSPECI:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003

PROVISIONAL SPECIFICATION
[See section 10, Rule 13]

PROCESS FOR GENERATING A MIXED MULTICOMPONENT VAPOR FOR PREPARATION OF MONOALKYL ETHERS OF DIPHENOLS.

CAMLIN FINE SCIENCES LTD., A COMPANY INCORPORATED UNDER THE COMPANIES ACT, 1956, WHOSE ADDRESS IS WICEL, PLOT NO. F/11 & 12, OPP. SEEPZ MAIN GATE, MIDC, MAROL, CENTRAL ROAD, ANDHERI (EAST), MUMBAI – 400 093, MAHARASHTRA, INDIA.

THE FOLLOWING SPECIFICATION DESCRIBES THE INVENTION.

Field of Invention
This invention pertains to monoalkyl ethers of diphenols. More particularly it pertains to a process for preparation of monoalkyl ethers of diphenols. Still more particularly it pertains to generating a mixed multi-component vapor for preparation of monoalkyl ethers of diphenols.
Description of the invention
One method of preparation of monoalkyl ethers of diphenols comprises reacting a diphenol or a diphenol derivative such as catechol, Hydroquinone, Resorcinol, 4-methyl catechol, 4-Chloro catechol etc. with lower alkyl alcohol such as Methanol, ethanol, Isopropyl alcohol, Isobutyl alcohol, tert-butyl alcohol, cyclohexanol etc. in vapor/gas state in presence of a phosphorus-containing catalyst. In this method, achieving a mixed vapor phase of the two reactants in proper proportion is a challenging task because the diphenol or a diphenol derivatives have higher boiling point whereas lower alkyl alcohols have comparatively lower boiling point. Hence, evaporating a solution of the diphenol or a diphenol derivatives with lower alkyl alcohol in conventionally known methods invariably results in higher proportion of lower alkyl alcohols in the resulting two-component vapor mixture. Further, if both these components are vaporized independently and then vapors mixed together prior to exposure to catalytic bed, it has been seen that significant degradation of the diphenol or a diphenol derivative occurs.
To achieve efficient conversion of the solution of diphenol or a diphenol derivative and lower alkyl alcohol, EP0914854 has disclosed An apparatus for generating a mixed multi-component vapor, comprising a thin film evaporator (1) having a feed inlet (1a) through which a mixed multi-component liquid comprising two or more liquid components different in boiling temperature from each other and soluble in or compatible with each other is fed into the evaporator and a delivery outlet (1b) through which a resultant mixed multi-component vapor is delivered from the evaporator; a feed line (2) for feeding the mixed multi-component liquid, connected to the feed inlet of the evaporator; a delivery line (5) for delivering the resultant mixed multi-component vapor, connected to the delivery outlet of the evaporator; and a forcedly liquid-circulating line (3) having a circulation inlet end (3a) connected to a delivery end side portion of the evaporator, a circulation outlet end (3b) connected to a feed side end portion of the evaporator and a liquid transporting means (4) arranged between the circulation inlet end and the circulation outlet end of the circulating line, whereby a non-evaporated portion of the mixed multi-component liquid is forcedly circulated through the circulation inlet end, the liquid transporting means and the circulation outlet end of the circulating line.
EP0914854 has also disclosed a process for generating a mixed multi-component vapor comprising the steps of: feeding a mixed multi-component liquid comprising two or more liquid components different in boiling temperature from each other and soluble in or compatible with each other into a feed side end portion of a thin film evaporator; evaporating the mixed multi-component liquid in the evaporator; and delivering a resultant mixed multi-component vapor from a delivery side end portion of the evaporator, wherein a non-evaporated portion of the mixed multi-component liquid present in the evaporator is forcedly circulated through a circulating line having a circulation inlet end connected to the delivery side end portion of the evaporator, a circulation outlet end connected to the feed side end portion of the evaporator, and forcedly liquid-transporting means located between the circulation inlet end and the circulation outlet end of the circulating line, by withdrawing the non-evaporated portion of the mixed multi-component liquid from the delivery side end portion of the evaporator through the circulation inlet end and returning the withdrawn non-evaporated portion of the mixed multi-component liquid into the feed side end portion of the evaporator through the forcedly liquid-transporting means and the circulation outlet end of the circulating line, thereby to promote the simultaneous evaporation of the two or more liquid components and the generation of a mixed multi-component vapor in which the two or more components are present in substantially the same composition as that of the mixed multi-component liquid.
However, this process and apparatus are capital intensive and inconvenient to operate. A simpler process involving simple equipment/apparatus was needed.
Process and apparatus of this invention comprise simpler apparatus and easier to operate process and yet gives acceptably good conversion to product.
It is an embodiment of this invention that the vapor mixture generation with desired mix of the diphenol or diphenol derivative and lower alkyl alcohol is achieved using a pre-heater (A) and Super-heater (B). It is a further embodiment of this invention that Jacketed section (C) is used to separate and discard the small amount of tar/ high boilers that is/are formed. It is also an embodiment of this invention that only the super-heated vapor mixture passes to next reactor to contact the catalyst.
Brief Description of figures and legends
Figure 1: Schematic diagram of process for generating a mixed multi-component vapor for preparation of monoalkyl ethers of diphenols.
A: Pre-heater, B: Super-heater, C: Jacketed section, D: Catalytic bed, 1: Feed inlet, 2: Vapor mixture, 3: Superheated vapors, 4: Superheated vapor feed to catalytic bed, 5: Product vapors for separation, 6: High boilers to drain, 7: Condensed product vapors to recycle, 8: Hot oil inlet to pre-heater, 9: Hot oil outlet from pre-heater, 10: Hot oil inlet to super-heater, 11: Hot oil outlet from super-heater, 12: Hot oil inlet to jacketed section, 13. Hot oil outlet from jacketed section.
The process scheme consists of mixing a diphenol or diphenol derivative such as catechol, Hydroquinone, Resorcinol, 4-methyl catechol, 4-Chloro catechol etc. with lower alkyl alcohol such as Methanol, ethanol, Isopropyl alcohol, Isobutyl alcohol, tert-butyl alcohol, cyclohexanol etc. in a mixing vessel at about 40 to 100 deg C. The mixed multi component liquid is then pumped into feed tank via in-line filter so as to separate any un-dissolved component. The clear multi component liquid in feed tank is analyzed & adjusted to desired composition by addition of required component. The said liquid is then transferred to pre-heater (A) & super-heater (B) heated by a heating source to get the superheated mixed multi component vapors from top of the Jacketed vessel (C). At the same time if some of the high boilers escape the process of super heating and condense, they are removed from the bottom as shown in the figure via “High Boilers to drain” so that only vapors are allowed to pass to next stage.
The superheated mixed multi component vapors are allowed to pass through a vertical externally heated (jacketed) section (c) through which hot oil goes in through (12) and comes out through (13) to facilitate the separation of the non-evaporated portion of the mixed multi component liquid. The heated section is being heated by a heating source to ensure the complete evaporation of the high boiling component of the mixed multi component liquid. The mixed multi component vapors, are ensured to have same composition as that of the multi-component liquid and are then transferred further to the vapor phase catalytic reactor (D).
The non evaporated portion of the mixed multi component liquid is drained from the bottom of the heated section (6).
The catalyst system used & further manufacturing process used for monoalkyl ether synthesis is as mentioned in WO 01/ 74485 A1 and the method of its preparation followed here has been described in description of the example below. Of course, in place of the catalysts described below, any other catalyst made by any other method that results in catalyzing a reaction between vapors of diphenol or diphenol derivative and lower alkyl alcohol to make monoalkyl ethers of diphenols can be substituted.
The catalyst used for this process, designated as ALPO catalyst, consists of Mixed oxides of elements such as Phosphorous & Aluminum and is prepared as mentioned in WO 01/74485 A1.
This invention may also be used for developing multi-component vapor mixture for reacting with each other in a catalytic reaction for preparation of producing a monoalkyl ether of a dihydric phenolic compound; the components of the vapor mixture comprising high boiler aromatic compounds having one or more hydroxyl group including, without limitation, phenol, guaiacol, catechol, hydroquinone, resorcinol, 2-methyl catechol, 4-methyl catechol, 2-methyl hydroquinone, 2-chlorocatechol and 4-chlorocatechol; and low boilers, including, without limitation, aliphatic alcohols, cycloaliphatic alcohols, aliphatic ethers, aliphatic ketones, aliphatic glycols, aliphatic carboxylic acid esters, aliphatic hydrocarbons, cycloaliphatic hydrocarbons, aromatic hydrocarbons and water, each having a boiling temperature of 50 to 200.degree. C.
In the following is described an illustrative example of this invention. The example is intended only as an illustration and does not limit the scope of the invention by any means by the specific reactants used and specific reaction conditions used. Variations from this example that are obvious to a person skilled in the art and obvious equivalents are considered to be within the scope of this invention.
Example
In a SS (Stainless Steel) reactor 4000 L capacity Catechol & Methanol was charged in a ratio 1: 20 moles. The ratio may also be 1:10; preferably 1:5 at room temperature under Nitrogen atmosphere. Heating was started to raise the temperature to about 50-70° C until a clear solution is formed.
In a Multiple tubular Reactor containing 146 tubes, the tubes were filled with heterogeneous ALPO catalyst (100kg -500kg.) in cube form of size 2 mm x 2 mm prepared as per example 2.
The length of each tube was 1000 to 1500 cm & diameter 72 cm. The tubular reactor was heated to 240 -300°C by circulating hot oil & kept under Nitrogen atmosphere throughout the course of the reaction.
The Catechol + Methanol hot solution (prepared as above) was passed through series of heaters & super heaters as described previously so as to eliminate any material in solid or liquid state . The vapors so formed are collected from (C) & fed at the rate of 250 L to 300L/ hr through the tubular reactor catalyst bed D. Te catalyst was prepared as described further below.
The reaction temperature is maintained within a range of 240-300 deg C during this operation so as to keep the reactants in vapor state during the reaction with the catalyst.
Thereafter, the vapors are cooled and the condensed liquid mass is then collected in a receiver. The typical content of this solution is as follows: Guaiacol – 50-60%, Veratrole – 1.2%, Catechol – 40-50% along with un-reacted Methanol & water formed in the reaction. The methanol & water was removed from above mixture. Methanol was recycled back to step I and water was discarded.
The Guaiacol & Veratrole Mixture cut was removed from the product mass through use of Thin Film evaporator (TFE) & the high boiling cut of Catechol left in the TFE was recycled.
The separation of Guaiacol & Veratrole was achieved by fractional distillation using 1000 to 1500 cm packed column (d = 60-70 cm) & under Vacuum.
Purity of Guaiacol – 99.75-99.85% & Veratrole – 0.2-0.3%. Yield 50 - 65%.
Residual mass consisting of mainly Catechol was sent to Step I without any distillation for reaction. Purity of Catechol was 97- 99%. The polymeric tars generated through continuous operation was eliminated from bottom of the reactor (8) as high boilers once in every 4 hours operation.
Preparation of catalyst
59.2 g of AlCl3.6 H2O were dissolved in 200 ml of 0.5N HCl (190 ml H2O +10 ml of 37 % HCl) with stirring. 21 ml of 85 % H3PO4 by weight are subsequently added. To the clear solution was then added drop-wise conc. NH4OH (about 90 ml) to adjust pH to about 7. The formed precipitate was subsequently dried by suction on a filter to obtain a paste. The paste was then dried in a static dryer at 120oC for 12 hours to obtain white mass, which was then treated in air stream at high temp, using following time table as follows: from room temp to 300oC at 10o/ min rate, keeping the temp of 300oC for 4 hours, subsequent heating from 300 to 600oC at 10o/min rate, keeping the temp. of 600oC for 4 hours. The surface area of the resulting sample was 74±5 m2/ g. The solid was then subjected to compression, granulation & sieving to obtain granules having average size ranging from 0.5 to 1 mm. The Al/P analytic ratio in the final catalyst determined by plasma spectrometry, was 0.064±0.04. The catalyst was then formed into square shapes of 2mm x 2mm by using standard methods as mentioned in the literature.
175 gm of this catalyst was mixed with 37.5 gm of binder (Kaolin or Bentonite clay procured from local supplier) & 37.5 gm of Polyvinyl Acetate (PVA) Powder in a sigma kneader. To this mixture was slowly added 210 ml of distilled water & kneading of mass continued so as to form a dough of a consistency similar to that required for bread making. This dough is then pressed in a mill so as to convert it in noodles shape. These noodles were slowly dried in a dryer at 100 deg C until constant weight is achieved. Total time required for drying is about 8 hours. Weight of dried product – 240 gm.
These noodles are then ground & passed through a 100 mesh sieve so as to convert it in fine powder. This powder is then passed through tabletting / pelleting machine so as to convert it in square shape of size 2mm x 2 mm. This square shaped catalyst has good hardness & strength. This square shaped catalyst is calcined at about 560 deg C temperature for 4 hours in Nitrogen atmosphere before using it for reaction.

Dated this 21st day of May, 2014.

FOR CAMLIN FINE SCIENCES LTD.
By their Agent

(MANISH SAURASTRI)
Agent No. IN/PA/291
KRISHNA & SAURASTRI ASSOCIATES

Name ; Camlin Fine Sciences Ltd. Sheet No. : 1

Appl. No. : /MUM/2014 Total Sheets : 1

Figure 1

(MANISH SAURASTRI)
Agent No. IN/PA/291
KRISHNA & SAURASTRI ASSOCIATES