Description:FORM 2

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

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
A CATALYST COMPOSITION FOR THE ALKYLATION OF AROMATIC COMPOUNDS

APPLICANT
VINATI ORGANICS LIMITED
An Indian entity
having address,
Parinee Crescenzo, "A" Wing, 11th floor, 1102,
'G' Block, Behind MCA, Bandra-Kurla Complex, Bandra (east),
Mumbai – 400051, India

The following specification describes the invention and the manner in which it is to be performed.
CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY
The present application claims no priority from any of the patent application(s).
TECHNICAL FIELD
The present invention relates to a catalyst composition for the alkylation of aromatic compounds. More specifically, this invention relates to a catalyst composition comprising a catalyst and a catalyst carrier in an aromatic hydrocarbon alkylation.
BACKGROUND
Catalysis is the backbone of many industrial processes, which use chemical reactions to turn raw materials into useful products. They are integral in manufacturing many items. The catalysis reaction depends on variety of factors such as type of temperature, pH, catalyst concentration, substrate concentration and presence of activators or inhibitors. Use of a proper catalyst in a large-scale industrial process can save lot of energy. Heterogenous catalysis is usually employed in large scale applications of synthesis of chemical products such as perfume industry, biofuel, petrochemical, etc.
Alkali metals are usually employed as catalyst for the alkylation and acylation reactions. Alkali metals are known in the art for their propensity for side-chain alkylation of alkyl aromatics or alkyl aromatic hydrocarbons. For instance, the catalyst having metallic sodium or potassium is dispersed onto the surface of a carrier. The carrier could be any support matrix having the capability of adsorbing metal onto its surface. Generally used carrier compounds are metal alkali carbonates and metal alkali bicarbonate. Compounds having a porous structure is employed in order to increase the available surface area for adsorption of the alkali metal catalyst.
The existing catalyst, however, suffers from several drawbacks which includes, but are not limited to, the inconvenient manufacturing and processing of the catalyst, less surface area, low yield of the required product, and decrease in the catalyst activity because of tar formation in the equipment. In addition, the catalyst is usually prepared ex-situ which further reduces the catalyst activity, reactivity, & product yield and increases the reaction time. Particularly in case of batch-type synthesis methods reduction of reaction time is an important factor.
Therefore, there is a long-felt need for an improved catalyst composition for the alkylation of aromatic hydrocarbons which can be prepared in-situ, having a good yield, minimum impurities, and requires less time for preparation. Further, the said improved catalyst composition can be implemented as an alternative to the use of porous support material which are difficult to maintain in a large-scale application.
OBJECTIVES OF THE INVENTION
The objective of the present inventive is to provide a catalyst composition having a good yield and no/minimum impurities.
Another objective of the present invention is to reduce the reaction time of the catalyst preparation reaction and thereby reducing overall reaction time, and to obtain an optimized particle size for better catalytic activity for its application in side-chain alkylation of aromatic compounds.
Also, yet another objective of the present invention is to replace the use of porous support material for catalyst as it is difficult to maintain for large applications.
SUMMARY
This summary is not intended to identify essential features of the claimed subject matter, nor is it intended for use in determining or limiting the scope of the claimed subject matter. This summary is provided to introduce concept related to composition of catalyst for alkylation of aromatic hydrocarbons, and the concepts are further described below in the detailed description.
In an embodiment of the present invention, a catalyst composition for the preparation of alkyl aromatic hydrocarbons may comprise a catalyst carrier, an alkali metal catalyst and an organic solvent, wherein the alkali metal catalyst in molten form is coated over a catalyst carrier and suspended in the organic solvent.
DETAILED DESCRIPTION
Reference throughout the specification to "various embodiments," "some embodiments," "one embodiment," or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases "in various embodiments," "in some embodiments," "in one embodiment," or "in an embodiment" in places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.
The words "comprising," "having," "containing," and "including," and other forms thereof are intended to be equivalent in meaning and be open-ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items or meant to be limited to only the listed item or items.
It must also be noted that the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Although any methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary methods are described. The disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms. Various modifications to the embodiment may be readily apparent to those skilled in the art, and the generic principles herein may be applied to other embodiments. However, one of ordinary skill in the art may readily recognize that the present disclosure is not intended to be limited to the embodiments illustrated but is to be accorded the widest scope consistent with the principles and features described herein. The detailed description of the invention will be described hereinafter referring to accompanied drawings.
The present invention intends to disclose a catalyst composition for the preparation of alkyl aromatic hydrocarbons, the composition comprising a catalyst carrier, an alkali metal catalyst, and an organic solvent wherein, the alkali metal catalyst in molten form is coated over the catalyst carrier and suspended in the organic solvent.
In one embodiment, the catalyst composition may comprise a predetermined amount of additive to form a uniform suspension of alkali metal catalyst in molten form coated over the catalyst in an organic solvent. The additive may be a suspending agent, dispersing agent, or a lubrication agent enabling uniform distribution of catalyst coated over carrier particles in the organic solvent. The said additive may be selected from dispersing agents such as fatty acids, hydrophobic materials, oleyl alcohol (OAh), oleylamine (OLA), and oleyl phosphate (OP), oleic acid, tall oil, palmitic acid, linoleic Acid, and stearic acid. In one embodiment, preferably an additive is the fatty acid selected from the group of but not limited to oleic acid, tall oil, palmitic acid, linoleic Acid, and stearic acid.
The catalyst composition may be used for alkylating aromatic hydrocarbons and is characterized in that the catalyst composition may be composed of a carrier material and alkali metal catalyst.
In an embodiment of the present invention, the catalyst carrier comprises at least one of potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate. The catalyst carrier is typically a solid material kept under certain conditions to carry, support or to load the catalyst which is usually inert but can contribute to catalytic activity.
In one embodiment of the present invention, the alkali metal catalyst comprises at least one of sodium, lithium, potassium, rubidium, caesium, NaK, Na2O. The said alkali metals used as catalyst are transition metals which are highly reactive and electropositive. These metals tend to lend or take electrons from other molecules easily thus increasing the rate of reaction. Alkali metals are employed in the reduction of organic compounds and in the preparation of many commercial compounds. More preferably, the alkali metal catalyst maybe selected as sodium.
The catalyst having metallic sodium or potassium is dispersed onto the surface of a carrier. The carrier could be any support matrix having the capability of adsorbing metal onto its surface. Generally used carrier compounds are metal alkali carbonates and metal alkali bicarbonate. Compounds having a porous structure is employed in order to increase the available surface area for adsorption of the alkali metal catalyst. Alternatively, in order to increase the surface area for the adsorption of alkali metal catalyst on the catalyst carrier, the catalyst carrier is crushed so that the molten alkali metal can form a coating layer on the surface of the carrier particles.
In one embodiment of the present invention, the said organic solvent may comprise at least one of aromatic hydrocarbon selected from but not limited to m-xylene, xylene, n-propylene, liquified isobutene. The said organic solvent is employed in the composition for the formation of a uniform mixture of the catalyst and the catalyst carrier. This solvent is usually inert and does not contribute to the catalysis reaction. However, the solvent may be a starting material in the reaction of an alkylation of aromatic compound which is also used as suspending solvent on a catalyst composition. In one embodiment, the said organic solvent is selected as m-xylene.
In one embodiment of the present invention, the said alkali metal catalyst is prepared in situ by following simultaneous crushing of the catalyst carrier and coating of the alkali metal catalyst in molten form over the catalyst carrier. In a related embodiment the said catalyst is used in applications such as alkylation of aromatic compounds. Alkylation of aromatic compound may include but not limited to preparation of n-propyl benzene, iso-butyl benzene, normal butyl benzene, secondary butyl benzene, tertiary amyl benzene, m-isobutyl toluene, styrene, olefins, etc.
In one embodiment of the present invention, the alkyl aromatic hydrocarbon is m-isobutyl toluene (MIBT). The catalyst composition as disclosed, improves yield and reduces the overall MIBT synthesis reaction time.
In another embodiment, the alkali metal catalyst is coated on the catalyst carrier in a ratio of 1:12 to 12:1 and preferably 1:10 to 10:1. In one embodiment, the ratio of the said alkali metal catalyst and organic solvent may be 1:1.1-2.
In another embodiment, the catalyst carrier has a particle size in the range of 0.6-0.9 mm.
In another embodiment, an amount of the dispersing agent is 0.1 g to 1g.
In one embodiment, the said catalyst carrier may be present in any form not limiting to powder, pellets, granules. More preferably, the said catalyst carrier is in a form of a crushed fine powder having a larger surface area. Larger surface area of means more surface area to form active sites thus leading to greater activity.
In another embodiment of the present invention, the particle size of the alkali metal catalyst coated over the catalyst carrier in a range of 25-100µm. In a preferred embodiment, the particle size of the catalyst coated over the carrier is >50µm. The layer coated on the carrier by the alkali metal catalyst is vital since too small layer might lead to lesser catalytic capacity further requiring more catalyst per batch reaction.
One of the advantages of the present invention is the use of a catalyst having catalyst alkali metal dispersed onto a carrier in presence of an aromatic hydrocarbon solvent further used for alkylation of aromatic hydrocarbons.
Experimental Details:
Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited to these examples.

Example 1: Preparation of catalyst
Catalyst carrier is prepared by adding K2CO3 in a catalyst drying unit and organic solvent is prepared by adding m-xylene in solvent drying unit. After the drying process both dried K2CO3 and m-xylene are added in the catalyst preparation apparatus. Sodium is added in the catalyst preparation apparatus and the apparatus is heated at 97°C to obtain molten sodium. Further, the crushing and coating of the carrier K2CO3 take place simultaneously and a uniform catalyst slurry is obtained which is directly added to the reactor for further downstream processing.

Example 2: Yield of m-isobutyl toluene (MIBT) using the said alkali metal catalyst
Table 1: Experimental details of m-isobutyl toluene (MIBT) production under different concentrations of alkali catalyst
Exp. No. Condition Moles of suspending solvent (m-xylene) Catalyst carrier (K2CO3) Catalyst
(Sodium) +dispersing agent MIBT %
1 catalyst coated over carrier and suspended in organic solvent in presence of a dispersing agent 7.60 106 12.5 37.19
2 catalyst coated over carrier and suspended in organic solvent in presence of a dispersing agent 7.60 106 10.9 36.97
3 catalyst coated over carrier and suspended in organic solvent in presence of a dispersing agent 7.60 106 10.7 35.74
4 Less qty. of catalyst without dispersing agent 7.60 75 7.5 9.42
5 No sodium added 7.60 106 0 0.68
6 Uncrushed K2CO3¬ without dispersing agent 7.60 106 10.5 14.63
7 Higher Moles of xylene charged 11.31 132 13.6 26.79

Production of MIBT was carried out using the sodium catalyst and the effect of different concentrations/conditions was observed in Table 1.
By referring to table 1 it is evident that organic solvent (m-xylene), catalyst carrier (K2CO3) and alkali metal catalyst in presence of a dispersing agent are taken in a defined form as discussed in various embodiments. Particularly, when the predetermined amounts of catalyst sodium in molten form and K2CO3 in crushed form is suspended in the m-xylene solvent the yield of MIBT is observed highest. Thus, MIBT product recovery is improved when the catalyst composition as shown.
Example 3: Yield of MIBT using different dispersing agents.
Table 2: Experimental details of m-isobutyl toluene (MIBT) production using different dispersing agents
Exp. No. K2CO3 Sodium MIBT Additives
1 106 12.4 37.19 2 gms Oleic Acid
2 106 10.231 4.68 2 gms Tall Oil
3 106 12.2 29.20 2 gms Stearic acid

Production of MIBT was carried out using the sodium catalyst, K2CO3 and the effect of different dispersing agents was observed in Table 2.
By referring to table 2 it is evident that addition of oleic acid as a dispersing agent is giving the maximum recovery of MIBT as compared with tall oil and stearic acid. Thus, to produce MIBT oleic acid may be used as a dispersing agent.
In one embodiment of the present invention, the said composition is enabled to improve the production of alkylation of aromatic hydrocarbons.
In another embodiment of the invention, the composition in accordance with the present invention may have the following advantages, including but not limited to:
• Uniform and consistent catalyst formation
• Improved catalytic activity
• Improves quality and quantity of catalyst obtained
• Improvement in the product yield such the up-to 40% MIBT is recovered.
• Reduced impurities formed during the formation of the desired product.
Although implementations for a composition of catalyst implemented thereon for the preparation catalyst used for the synthesis of alkylated aromatic hydrocarbons have been described in language specific to structural features and/or processes, it is to be understood that the appended claims are not necessarily limited to the specific features or processes described. Rather, the specific features and processes are disclosed as examples of implementations of for a composition of catalyst implemented thereon for the preparation catalyst used for the synthesis of alkylated aromatic hydrocarbons.
, Claims:WE CLAIM:
1. A catalyst composition for preparation alkyl aromatic hydrocarbons, the composition comprising:
a. a catalyst carrier;
b. an alkali metal catalyst; and
c. an organic solvent;
wherein the alkali metal catalyst in molten form is coated over the catalyst carrier and suspended in the organic solvent.

2. The catalyst composition as claimed in claim 1, wherein the said carrier comprises at least one of potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate.

3. The catalyst composition as claimed in claim 1, wherein the said alkali metal catalyst comprises at least one of sodium, lithium, potassium, rubidium, cesium, NaK, Na2O.

4. The catalyst composition as claimed in claim 1, wherein the said organic solvent comprises at least one of m-xylene, p-xylene, n-propylene, liquified isobutene.

5. The catalyst composition as claimed in claim 1, wherein the alkyl aromatic hydrocarbon is m-isobutyl toluene (MIBT).

6. The Catalyst composition as claimed in claim 1, comprises a dispersing agent selected from at least one of oleic acid, tall oil, stearic acid, linoleic acid, palmitic acid.

7. The Catalyst composition as claimed in claim 6, wherein the dispersing agent is added in a range of 0.1 to 1g.

8. The catalyst composition as claimed in claim 1, wherein the said alkali metal catalyst is coated on the catalyst carrier in a ratio of 1:12 to 12:1.

9. The catalyst composition as claimed in claim 1, wherein the ratio of the said alkali metal catalyst and the organic solvent is 1:1.1 to 1:2.

10. The catalyst composition as claimed in claim 1, wherein the catalyst carrier has a particle size of 0.6-0.9mm.

11. The catalyst composition as claimed in claim 1, wherein the catalyst carrier is in a form of a crushed fine powder having a larger surface area.

12. The catalyst composition as claimed in claim 1, wherein the particle size of the said alkali metal catalyst coated over the catalyst carrier is >50µm.

13. The catalyst composition as claimed in claim 1, wherein the said alkali metal catalyst is prepared in situ by following simultaneous crushing of the catalyst carrier and coating of the alkali metal catalyst in molten form over the catalyst carrier.
Dated this 02nd Day of August 2022