CROSS-REFERENCE TO RELATED APPLICATION AND PRIORITY

The present application claims priority from Indian complete patent application no. 202121060665 filed on the 24 December 2021, the details of which are incorporated herein by a reference.

FIELD OF INVENTION

The present subject matter relates to the field of a sulfonating agent preparation reactor, and more particularly relates to an oleum preparation reactor in Acrylamido tertiary butyl sulfonic acid monomer preparation.

BACKGROUND OF INVENTION

The subject matter discussed in the background section should not be assumed to be prior art merely because of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also correspond to implementations of the claimed technology.

Polymers of acrylamide monomers such as acrylamido tertiary butyl sulfonic acid (hereinafter may be interchangeably referred to as ‘ATBS’) and its copolymers are vastly used in various applications such as enhanced oil recovery, as the sulfonated polymers containing ATBS can be used in higher temperature and salinity conditions and impart thickening and fluid properties. The homopolymers and copolymers produced from ATBS monomer possess a crucial role in various industrial processes such as flooding and gel treatment agent in enhanced oil recovery, thickening agent in paints and emulsion, water absorbent material, cosmetic products, and pharmaceutical products. In a preparation process of ATBS monomer, a reactivity and acid number of a sulfonating agent has direct effect on the ATBS yield, purity, and impurity profile.

In state of art, a preparation of a sulfonating mixture in a synthesis process of ATBS is carried out in an agitated reactor comprising stirrer means. Stirred mixing of the sulfonating mixture results into formation of a sulfonating agent having inconsistent acid number and strength. The inconsistent acid number of the sulfonating mixture affects yield, purity, and appearance of ATBS compound.

Further, an inconsistent mixing of the sulfonating agent may result in presence of free/excess SO3 and SO2 ions inducing degradation and decomposition of organic molecules and imparting yellow colour to the ATBS compound and thereby affecting the purity and quality of an ATBS monomer. The range of acid number during ATBS monomer formation in the reaction is vital in order to achieve quality as well as yield.

Therefore, there is long standing need for an environment friendly, simple, and inexpensive modified oleum reactor for preparation of sulfonating mixture having a predefined strength with increased reactivity along with ease in working, and handling in an economical manner.

OBJECTIVES OF THE INVENTION

The main objective of the present subject matter is to provide an oleum reactor for preparation of sulfonating mixture with a consistent strength and to effectuate and control an acid number to a predefined range and increasing yield of acrylamido tertiary butyl sulfonic acid monomer.

Another objective of the present subject matter is to provide a process of preparing sulfonating mixture in an oleum reactor for synthesis of acrylamido tertiary butyl sulphonic acid.

Yet another objective of the present subject matter is to implement an oleum reactor and process of preparing sulfonating mixture which can exert steady moisture content during ATBS monomer preparation and reducing side product and impurity formation.

Yet another objective of the present invention is to control the yellowness of final ATBS monomer by controlling free SO3 in the sulfonating mixture and thus providing a clear coloration to a synthesized acrylamido tertiary butyl sulfonic acid product.

SUMMARY OF THE INVENTION

Before the present system, processes, method, and products are described in the said proposed subject matter, it is to be understood that the disclosed subject matter is not limited to the specific process, methods, and products as described herein, as there can be multiple possible embodiments which are not expressly illustrated in the present subject matter but may still be practicable within the scope of the subject matter.

This summary is provided to introduce concepts related to an oleum reactor and a process for preparing a sulfonating mixture in Acrylamido tertiary butyl sulfonic acid synthesis and the concepts are further described below in the detailed description. This summary is not intended to identify essential features of the claimed subject matter, nor it is intended for use in determining or limiting the scope of the claimed subject matter.

The instant subject matter describes about an oleum reactor and for preparing a sulfonating mixture in Acrylamido tertiary butyl sulfonic acid. The instant subject matter further describes a process of implementation of claimed oleum reaction for preparing a sulfonating mixture having a consistent strength and acid number.

In an embodiment of the present subject matter, an oleum reactor for preparing a sulfonating mixture in a synthesis of acrylamido tertiary butyl sulfonic acid monomer is disclosed. The oleum reactor may comprise a horizontal tank reactor comprising a plurality of baffles. The oleum reactor may further comprise a 98% sulfuric acid inlet at one side of the horizontal tank reactor. Further, the oleum reactor may comprise a 30% oleum inlet at another side of the horizontal tank reactor. The oleum reactor may further comprise a plate heat exchanger (PHE) affixed to the horizontal tank reactor in a circular conduit connection. Further, the oleum reactor may comprise a scrubber system in a vent line of the horizontal tank reactor. The oleum reactor may further comprise a discharge tank for storage of the sulfonating mixture.

In another embodiment of the present subject matter, a process of preparing a sulfonating mixture in an oleum reactor in the synthesis of acrylamido tertiary butyl sulfonic acid is disclosed. The process may comprise a step of inletting a predefined amount of 98% sulfuric acid in a sulfuric acid storage tank from one side of a horizontal tank reactor comprising a plurality of baffles. The process may further comprise a step of circulating 98% sulfuric acid via a circular conduit connection, and a plate heat exchanger affixed to the horizontal tank reactor. The process may further comprise a step passing the 98% sulfuric acid from a scrubber system in a vent line of the horizontal tank reactor to scrub off fumes from the horizontal tank reactor. The process may further comprise a step of sparging a predefined amount of 30% oleum into the horizontal tank reactor from another side of the horizontal tank reactor. The process may further comprise a step turbulent mixing of a 30% oleum with 98% sulfuric acid to obtain a sulfonating mixture via a plurality of baffles for a predefined time period. Furthermore, the process may comprise a step of collecting the sulfonating mixture in a discharge tank jacketed with N2 gas.

BRIEF DESCRIPTION OF DRAWINGS

The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to refer like features and components.

Figure 1 depicts a conventional stirred reactor system (100) for preparation of sulfonating mixture.

Figure 2 depicts an implementation of an oleum reactor (200) for preparation of sulfonating mixture, in accordance with an embodiment of the present subject matter.

Figure 3 depicts a scrubber unit (212) in a vent line of the oleum reactor, in accordance with an embodiment of the present subject matter.

Figure 4 depicts a process (400) for preparation of a sulfonating mixture in an oleum reactor, in accordance with an embodiment of the present subject matter.

DETAILED DESCRIPTION OF THE INVENTION

Some embodiments of this disclosure, illustrating all its features, may now be discussed in detail. 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 subject matter, wherein the exemplary methods are described. The disclosed embodiments are merely exemplary of the disclosure of the present subject matter, which may be embodied in various forms.

It may be understood by all readers of this written description that the example embodiments described herein and claimed hereafter may be suitably practiced in the absence of any recited feature, element or step that is, or is not, specifically disclosed herein. For instance, references in this written description to "one embodiment," "an embodiment," "an exemplary embodiment," and the like, indicate that the embodiment described can include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. The disclosed embodiments are merely exemplary of various forms or combinations. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one of ordinary skill in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

No terminology in this application should be construed as indicating any non-claimed element as essential or critical. The use of any and all examples, or example language (e.g., "such as") provided herein, is intended merely to better illuminate example embodiments, and does not pose a limitation on the scope of the claims appended hereto unless otherwise claimed.

Recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. Where a specific range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is included therein. All smaller sub-ranges are also included. The upper and lower limits of these smaller ranges are also included therein, subject to any specifically excluded limit in the stated range.

The main purpose of the disclosed subject matter is to provide a safe, easy, and cost- effective oleum reactor configured for preparing a sulfonating mixture with improved reactivity and consistent acid number.

Referring to Figure 1, a conventional stirred reactor (100) for preparing a sulfonating mixture is illustrated. In the conventional reactor the sulfonating mixture is prepared by simultaneously adding sulfuric acid (H2SO4) and liquid SO3. The conventional stirred reactor (100) further carries out mixing of sulfuric acid (H2SO4) and liquid SO3 by means of a stirrer.

The use of conventional stirred reactor (100) is observed to be less efficient and provides a sulfonating mixture with inconsistent strength and further causes variation in moisture content and acid number during ATBS monomer preparation. Further, the stirred type of oleum reactor (100) leads to excess heat dissipation and also produces harmful fumes.

Accordingly, the present subject matter is directed to provide an improved oleum reactor for preparing a sulfonating mixture in a synthesis of acrylamido tertiary butyl sulfonic acid monomer. Further, the subject matter discloses a process for preparing a sulfonating mixture in an oleum reactor in a synthesis of acrylamido tertiary butyl sulfonic acid in accordance with the embodiments of the present subject matter.

Referring to Figure 2, an oleum reactor (200) assembly for preparing a sulfonating mixture in a synthesis of acrylamido tertiary butyl sulfonic acid (ATBS), is illustrated in accordance with an embodiment of the present subject matter.

In one embodiment, the oleum reactor (200) is a horizontal non-agitated cylindrical reactor tank configured for a preparation of highly reactive sulfonating mixture having a predefined consistent strength and enabling a uniform acid number and moisture content in the ATBS monomer synthesis.

The oleum reactor (200) may comprise components such as a 98% sulfuric acid storage tank (201), a 30% oleum storage tank (202), a horizontal tank reactor (203), a 98% sulfuric acid inlet (204), a 30% oleum inlet (205), a plate heat exchanger unit (206), a circulation pump unit (207), a cooling water inlet (208), a cooling water outlet (209), a circulation conduit connection (210), a plurality of baffles (211) affixed to the horizontal tank reactor (203), a scrubber system (212) in a vent line, a sulfonating mixture storage unit (213) comprising a storage tank and a day tank.

In one embodiment, the horizontal tank reactor (203) may be selected as a static reactor having a plurality of baffles (211). The horizontal tank reactor (203) may be selected as a horizontal cylindrical tank reactor.

The 30% oleum inlet (205) may be configured for inletting 30% oleum to the horizontal tank reactor (203) from 30% oleum storage tank (202). The 30% oleum inlet (205) may comprise a sparger (not shown) comprising a plurality of pores configured for inletting the 30% oleum in the horizontal tank reactor (203) by a sparging mechanism. The sparging of the 30% oleum enables uniform distribution of 30% oleum in a 98% circulating sulfuric acid. The 98% sulfuric acid inlet (204) may be configured for inletting 98% sulfuric acid to the horizontal tank reactor (203) from a 98% sulfuric acid storage tank (201). The horizontal tank reactor (203) may be connected to components such as the circulation pump unit (207), the plate heat exchanger unit (206), the cooling water inlet (208), and the cooling water outlet (209), through a circulation conduit connection (210). The circular conduit connection (210) may be configured for circulating a 98% sulfuric acid through a scrubber system (212), plate heat exchanger unit (206) and the horizontal tank reactor (203).

In one embodiment, the circular conduit connection (210) may be enabled for simultaneous passage and gradual turbulence mixing of 30% oleum and 98% sulphuric acid in a circular motion in a predefined ratio via the coaxially mounted baffles (211). In an embodiment, a turbulence mixing of 98% sulfuric acid and 30% oleum in the oleum reactor enables white colour retention of an ATBS monomer slurry product.

In one embodiment, the plate heat exchanger unit (206) may be connected to the horizontal tank reactor (203) via the circular conduit connection (210). The 98% sulfuric acid may be pumped to the plate heat exchanger unit (206) via the circulation pump unit (207). The said plate heat exchanger unit (206) may be configured to control the heat of mixing via jacketed cooling through cooling water inlet (209), and cooling water outlet (210) arrangement. In one embodiment, the plate heat exchanger (PHE) (206) is configured to control the reaction temperature between 30-50°C and more preferably between 30-40°C.

In an embodiment, the plurality of baffles (211) of the horizontal tank reactor (203) may be mounted internally to the horizontal tank reactor (203) at an equidistant position and disposed coaxially at an alternate locale. In one embodiment, % baffle cut of each of the baffles (211) may be between 30-40% and preferably 35%. In one embodiment, number of baffles (211) affixed to the horizontal tank reactor (203) may be between 2-7 and preferably 3. In one embodiment, the plurality of baffles (211) may be coaxially mounted metallic plates each having thickness of 8 mm. In one embodiment, the arrangement of baffles in the horizontal tank reactor (203) is configured to reduce the residue content of the sulfonating mixture below 22%.

Referring to Figure 3, a scrubber system (212) in a vent line of the horizontal tank reactor (203) is described in detail. The scrubber unit (212) may comprise components such as sparger (301), column packings (302), vent line inlet (303) connected to the horizontal tank reactor (303) and a collection area (304) comprising. The scrubber system (212) may be enabled for scrubbing any fumes generated during mixing of 98% sulfuric acid and 30% oleum in a predefined ratio and collecting the clarified sulfuric acid in a collection area (304) and passing the clarified sulfuric acid to the plate heat exchangers via the circulation pump unit (207) and thereby reducing the environmental impact of preparing a sulfonating mixture.

In one embodiment of the present subject matter, the oleum reactor (200) may comprise the sulfonating mixture storage unit (213) comprising a storage tank and a day tank configured for recovering and storing the sulfonating mixture having a predefined ratio. The sulfonating mixture storage unit (213) is blanketed by N2 maintaining a predefined strength of the sulfonating mixture for a prolonged period.

Referring to Figure 4, a process (400) of preparing a sulfonating mixture in the said oleum reactor (200) is depicted, in accordance with an embodiment of the present subject matter. The process (400) of preparing the sulfonating mixture by the said oleum reactor provides a consistent strength and acid number between 35-37 to the ATBS monomer.

The process (400) may comprise a step of inletting (401) a predefined amount of 98% sulfuric acid in the sulfuric acid storage tank (201) from one side of a horizontal tank reactor (203) comprising a plurality of baffles (211).

The process (400) may comprise a step of circulating (402) 98% sulfuric acid via a circular conduit connection (210), and a plate heat exchanger (206) affixed to the horizontal tank reactor (203) at a predefined rate. In one embodiment, a rate of circulation may be adjusted between 15-25 m ³ /hr and preferably 20 m ³ /hr. In an embodiment, the circulation of 98% sulfuric acid via the circular conduit connection (210), and the plate heat exchanger (206) controls a reaction temperature between 30- 50°C and preferably between 30-40°C.

The process (400) may comprise a step of passing (403) the 98% sulfuric acid from a scrubber system (212) in a vent line of the horizontal tank reactor (203) to scrub off fumes from the horizontal tank reactor (203).

The process (400) may comprise a step of sparging (404) a predefined amount of 30% oleum into the horizontal tank reactor (203) from another side of the horizontal tank reactor (203) at a predefined flow rate. In one embodiment, a rate of sparging of 30% oleum is adjusted between 2000-3000 kg/hr and preferably 2500-2700 kg/hr. The process (400) may comprise a step of turbulent mixing (405) of a 30% oleum with 98% sulfuric acid to obtain a sulfonating mixture via a plurality of baffles (211) for a predefined time period. At the step of turbulent mixing (405), the mixing ratio of 30% oleum with 98% sulfuric acid may be maintained within a range of 0.09 to 0.25:1. Preferably, at step (405), the mixing ratio of 98% sulfuric acid with 30% oleum is maintained within a range of 0.09:0.25:1 and preferably 0.12 to 0.20:1. In one embodiment, the predefined time period for turbulent mixing (405) of a 30% oleum with 98% sulfuric acid to obtain a sulfonating mixture via a plurality of baffles (211) is between 0.5-1 Hrs.

The process (400) may comprise a step of collecting (406) the sulfonating mixture in a discharge tank (213) jacketed with N2 gas.

The instant subject matter is further described by way of the following examples:

Experimental Details: Preparation of a Sulfonating mixture by using liquid SO3 in a conventional agitated reactor (100)

The process involves the batchwise mixing of liquid SO3 in 98% H2SO4. A batch quantity of 98% H2SO4 is taken in an agitated batch reactor. As the agitation is established, controlled addition of liquid SO3 is started in order to mix it in 98% H2SO4 to form a concentrated sulfonating mixture. The mixing ratio of liquid SO3 to 98% H2SO4 is 0.03 to 0.07. The addition time is maintained as 0.5 to 1 hr. During agitated mixing, the heat of mixing is removed by cooling water provided to limpet coil of the batch reactor. As the addition is completed, the strength of sulfonating mixture formed in reactor is checked and the complete batch of sulfonating mixture is transferred to storage tank. Preparation of a Sulfonating mixture by using 30% SO3 in a modified oleum reactor (200)

This process involves the turbulent mixing of 30% SO3 in 98% H2SO4 passing in a circular loop. A batch quantity of 98% H2SO4 is taken in a static batch reactor. It is circulated in the same reactor by means of a centrifugal pump. As the circulation is established, a controlled addition of 30% SO3 is started via a sparger to 98% H2SO4 in a circular flow to form a concentrated sulfonating mixture. The mixing ratio of 30% SO3 to 98% H2SO4 is maintained within the range of 0.12 to 0.20:1. The addition and mixing time is adjusted between 2 to 3 hrs. During mixing, a generated heat of mixing is removed by a plate heat exchanger mounted in the circulation line. The fumes are removed by using a scrubber unit in a vent line of the modified oleum reactor. As the mixing is completed, the strength of sulfonating mixture formed in reactor is checked, and then the complete batch of sulfonating mixture is transferred to storage tank.

Example 3: Comparative analysis of strength of sulfonating mixtures prepared in Example 1 and 2

Referring to Table 1 below a comparative data showing improvement in consistency and steady strength preparation of a sulfonating mixture are disclosed herewith. Table 1 specifically discloses a comparative data of six consecutive preparation batches of the sulfonating mixture in an oleum reactor (200) and a conventional stirred reactor (100).

Table 1

Referring to Table 1, a variation in strength of the sulfonation mixture was observed, when a conventional stirred reactor was used in the sulfonating mixture preparation process. When the conventional stirred reactor (100) was replaced with a modified oleum reactor (100) as described in the various embodiments of the present disclosure, an improvement in sulfonating mixture strength was observed in view of consistency and steady value within 99.79% -99.99% .

Example 4: Details of Example 4 describes a Comparison ATBS compound synthesized by using a sulfonating mixture prepared by Conventional stirred reactor and Modified oleum reactor based. The comparative details of ATBS monomer such as Appearance, Acid number, moisture of reaction mass filtrate when the Conventional stirred reactor and Modified oleum reactor are incorporated in preparation of sulfonating mixture is tabulated below in Table 2 and 3.

Table 2 (Data where conventional stirred reactor (100) was implemented)

Table 3 (Details where modified oleum reactor (200) was implemented)

Table 4 (Summary of comparative average data of ATBS where conventional stirred reactor (100) and modified oleum reactor (200) was implemented)

Referring to the details of Table 2, 3 and 4 it is observed that no or minimal variation in acid number and moisture of the filtrate was achieved in case of modified oleum reactor (200) having a static mixing mechanism implementation rather than conventional stirred reactor having agitated mixing mechanism. It is also observed that yellowness index (APHA) had a reduced value showing white appearance of a final ATBS product where a modified oleum reactor (200) was implemented. The reduction in moisture content during ATBS formation by implementing the modified oleum reactor (200) reduces moisture induced and SO3 induced impurity formation during ATBS synthesis.

Example 5: A sulfonating mixture prepared by implementing oleum reactor (200) and a conventional stirred reactor (100) was incorporated as a starting material in a synthesis of ATBS. The comparative details of HPLC analysis showing the impurity profile are tabulated in the below Table 5.

Table 5

Acrylamide (AM), Acrylonitrile (ACN), Isobutyl di-sulfonic acid (IBDSA), Isobutyl sulfonic acid (IBSA), Tertiary butyl acrylamide (TBA), Acrylamido methyl propane di-sulfonic acid (AMPDSA), Acrylamido tert-butyl sulfonic acid (ATBS)

Referring to Table 5 it is found that the content of impurities in final ATBS product were reduced when a sulfonating mixture prepared by the oleum reactor (200) was used as a starting material in the ATBS synthesis process. In accordance with embodiments of the present subject matter, the said oleum reactor (200) and the process (400) of preparing the sulfonation mixture in the oleum reactor (200) in the synthesis of ATBS provides following advantages but not limited to:

• Improvement & steadiness in resulting Sulfonating mixture.

• Steadiness in Acid numbers & moisture of ATBS reaction filtrate, and colour of ATBS product.

• Reduction in SO3 and moisture induced impurities during ATBS monomer formation.

• Improvement in quality of ATBS product.

The embodiments, examples, and alternatives of the preceding paragraphs or the description and drawings, including any of their various aspects or respective individual features, may be taken independently or in any combination thereof. Features described in connection with one embodiment apply to all embodiments unless such features are incompatible.

Although implementations for an oleum reactor for preparing a sulfonating mixture in a synthesis of acrylamido tertiary butyl sulfonic acid monomer 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 an oleum reactor for preparing a sulfonating mixture in a synthesis of acrylamido tertiary butyl sulfonic acid monomer.