Description: FIELD OF INVENTION
[001] The present invention relates to a method for synthesis of Iodobenzene diacetate. More particularly, the present invention relates to a method for synthesis of Iodobenzene diacetate using freshly prepared Peracetic acid, resulting in high yield of Iodobenzene diacetate.

BACKGROUND OF THE INVENTION
[002] Iodobenzene diacetate is a hypervalent iodine chemical reagent having a chemical formula C6H5I(OCOCH3)2. Iodobenzene diacetate comprises of hypervalent iodine (III) compounds that function as oxidizing agents due to the stability and selectivity of such compounds. Iodobenzene diacetate also function as an essential reagent in the formation of a wide range of heterocyclic compounds.

[003] Iodobenzene diacetate, being an oxidizing agent, possess a number of applications. It serve an essential purpose in industrial, and medical industry. Iodobenzene diacetate is also used in antiseptics and disinfectants for humans and animals as well as polarizing films for liquid crystal display [LCD] chemicals, and pharmaceutical intermediates. Iodine derivatives are also utilized as analytical reagents, organic building blocks, etc. Further, it also serve as an essential reagent for synthesis of a large variety of heterocyclic compounds.

[004] Some of the conventional method for synthesis of Iodobenzene diacetate employs Sodium Perborate tetrahydrate and acetic anhydride. However, acetic anhydride exhibits a number of disadvantages such as acetic anhydride is extremely corrosive and thus banned. Further, acetic anhydride pose a number of risk to human health such as acetic anhydride cause irritation and/or burning sensation in eyes and skin of people, possibly resulting in damage to eyes. Furthermore, inhalation of acetic anhydride may cause irritation in throat, nose, and mouth of people. Inhalation of acetic anhydride at higher concentration may damage the lungs.

[005] There are several patent literature that discloses a method for preparation of Iodobenzene diacetate. One such Japanese Patent Application JP2003238496A discloses a method for producing an Iodo-aromatic compound diacetate by reacting an Iodo-aromatic compound with Peracetic acid. However, the cited prior art includes an incubation temperature of 50? after addition of Peracetic acid into Iodobenzene. However, such temperature may not be able to control/minimize risk factors involved during the synthesis of Iodobenzene diacetate.

[006] Another Japanese Patent Literature JP2001354617A relates to an improvement in a method for acetylating iodine of an iodinated aromatic hydrocarbon with Peracetic acid. Acetylates of iodinated aromatic hydrocarbons, such as Iodobenzene diacetate, are useful for the oxidation of glycol diacetate from olefins to the corresponding azo-compounds of aromatic amines, ring acetylation of N-arylacetamides, and the like. The amount of Peracetic acid used in the cited prior art affects the yield of Iodobenzene diacetate such as the amount of Peracetic acid used in the cited prior art i.e. less than 3 moles may not result in high yield of Iodobenzene diacetate.

[007] In view of the above problems associated with the state of the art, there is a need of a method for producing high yield of Iodobenzene diacetate using freshly prepared Peracetic acid with enhanced activity and stability.

OBJECTIVES OF THE INVENTION
[008] The primary objective of the present invention is to provide a method for synthesis of Iodobenzene diacetate.

[009] Another objective of the present invention provides a method for synthesis of Iodobenzene diacetate using freshly prepared Peracetic acid, resulting in high yield of Iodobenzene diacetate.

[0010] Another objective of the present invention is to provide a method for preparation of freshly prepared Peracetic acid exhibiting 35% activity and enhanced stability.

[0011] Another objective of the present invention is to eliminate the use of acetic anhydride & Sodium Perborate tetrahydrate for the synthesis of Iodobenzene diacetate.

[0012] Another objective of the present invention is to maintain a desired reaction temperature so as to control/regulate risk factors involved during the synthesis of Iodobenzene diacetate.

[0013] Another objective of the present invention is to simplify the overall process for the synthesis of Iodobenzene diacetate.

[0014] Other objectives and advantages of the present invention will become apparent from the following description taken in connection with the accompanying drawings, wherein, by way of illustration and example, the aspects of the present invention are disclosed.

[0015] Another objective of the present invention is to eliminate the use of solvents, and directly crystalizing the product by chilling the reaction mass.

BRIEF DESCRIPTION OFDRAWINGS
[0016] The present invention will be better understood after reading the following detailed description of the presently preferred aspects thereof with reference to the appended drawings, in which the features, other aspects and advantages of certain exemplary embodiments of the invention will be more apparent from the accompanying drawing in which:
[0017] Figure 1 illustrates Fourier transform infrared (FT-IR) spectra of Iodobenzene Diacetate; and
[0018] Figure 2 and Figure 3 illustrates Nuclear Magnetic Resonance (NMR) spectra of Iodobenzene diacetate.
SUMMARY OF THE INVENTION
[0019] The present invention relates to a method for synthesis of Iodobenzene diacetate. The present invention relates to a method for synthesis of Iodobenzene diacetate. The adding Peracetic acid (l) drop wise in Iodobenzene (l) within 1.5 to 2 hours in a molar ratio of 1:3.3 and at a temperature ranging between 15?-35?; stirring uniformly the obtained solution; mixing the obtained solution, incubating the prepared solution for 2 to 4 hours at a temperature ranging between 15? to 35?; cooling the obtained solution at a temperature ranging between 0?-10?, forming a slurry; filtering the slurry; and drying the filtered solid in a dryer, resulting in the production of Iodobenzene diacetate.

DETAILED DESCRIPTION OF THE INVENTION

[0020] The following detailed description and embodiments set forth herein below are merely exemplary out of the wide variety and arrangement of instructions which can be employed with the present invention. The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. All the features disclosed in this specification may be replaced by similar other or alternative features performing similar or same or equivalent purposes. Thus, unless expressly stated otherwise, they all are within the scope of the present invention.

[0021] Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

[0022] The terms and words used in the following description and claims are not limited to the bibliographical meanings but are merely used to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purposes only and not for the purpose of limiting the invention.

[0023] It is to be understood that the singular forms “a”, “an” and “the” include plural referents unless the context clearly dictates otherwise.

[0024] It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps, or components but does not preclude the presence or addition of one or more other features, integers, steps, components, or groups thereof.

[0025] Accordingly, the present invention relates to a method for synthesis of Iodobenzene diacetate. More particularly, the present invention relates to a method for synthesis of Iodobenzene diacetate using freshly prepared Peracetic acid, resulting in high yield of Iodobenzene diacetate.

[0026] In an embodiment, the method for synthesis of Iodobenzene diacetate involves reaction between Iodobenzene and freshly prepared Peracetic acid as provided below:

Wherein,
(A) = Iodobenzene
(B) = Peracetic acid
(C) = Iodobenzene diacetate

[0027] In an embodiment, the present invention provides a method for the synthesis of Iodobenzene diacetate. The method involves preparing Iodobenzene diacetate using freshly prepared Peracetic acid exhibiting 35% activity and enhanced stability. The method comprises of the following steps :
(a) adding Peracetic acid (l) drop wise in Iodobenzene (l) within 1.5 to 2 hours in a molar ratio of 1:3.3 and at a temperature ranging between 15?-35?;
(b) stirring uniformly the solution obtained at step (a);
(c) mixing the solution obtained in step (b);
(d) incubating the solution prepared at step (c) for 2 to 4 hours at a temperature ranging between 15? to 35?;
(e) cooling the solution obtained at step (d) at a temperature ranging between 0?-10?, forming a slurry;
(f) filtering the slurry obtained at step (e); and
(g) drying the filtered solid obtained step (f) in a dryer, resulting in the production of Iodobenzene diacetate.

[0028] In an embodiment, Peracetic acid used in the present invention is in a concentration of 25-40 weight percentage.

[0029] In an embodiment, the reactor used in the present invention for mixing the contents of the flask may include such as, but not limited to, glass line reactor.

[0030] In an embodiment, the dryer used in the present invention for drying the filtered solid may include such as, but not limited to, tray dyer.

[0031] In an embodiment, the Iodobenzene diacetate is synthesized in solid form.

[0032] In an embodiment, Iodobenzene diacetate synthesized in the present invention is in a range of 90% - 92%.

[0033] In an exemplary embodiment, the apparatus used for mixing the solution obtained in step (b) may include, such as, but not limited to, a reactor.

[0034] In an embodiment, the process for preparation of Peracetic acid comprises of the following steps:
(a) adding sulphuric acid (l) to acetic acid (l) in a molar ratio of 1:0.006 (acetic acid : sulphuric acid);
(b) stirring uniformly the solution obtained in step (a);
(c) adding hydrogen peroxide (l) drop wise into the solution obtained in step (b) within 1.5 to 2 hours such that the molar ratio of acetic acid and hydrogen peroxide is 1:0.40 and at a temperature ranging between 25°C-35°C; and
(d) incubating the solution obtained in step (c) for 8 to 10 hours at a temperature ranging between 25°C to 40°C, resulting in preparation of aqueous solution of Peracetic acid.

[0035] In an embodiment, the Hydrogen peroxide used in the present invention for the preparation of Peracetic acid is in a concentration of 25-50 weight percentage. After completion of the reaction, the concentration of unreacted Hydrogen Peroxide is less than 5 %.

[0036] In an embodiment, the Peracetic acid prepared in the present invention exhibits 35% activity and enhanced stability.

[0037] In an embodiment, the Iodobenzene diacetate prepared in the present invention may exhibit a number of applications such as, but not limited to, as an intermediate in active pharmaceutical ingredients (API) and in industries such as cosmetics, dyes, and the like.

[0038] The present invention will be described in detail with reference to specific examples provided below. However, such examples should not be construed to limit the scope of the present invention.

EXAMPLE 1
[0039] The method for preparation of Iodobenzene diacetate involves addition of 51grams (0.25mol) of Iodobenzene in a 1litre three necked round bottom flask followed by adding 178.5grams(0.82mol) of 35% Peracetic acid drop wise into the flask at a temperature ranging between 15°C-35°C for two hours along with uniform stirring, so as to control drop in temperature. The method further involves mixing the contents in the flask, and incubating the prepared solution for two hours a temperature ranging between 15°C-35°C. The prepared solution is then cooled at a temperature ranging between 0°C-10°C. The slurry is then filtered. The prepared solid is then dried in a dryer, resulting in the production of 74.4 grams & 92% yield of Iodobenzene Diacetate.

EXAMPLE 2
[0040] The method for preparation of Iodobenzene diacetate involves addition of 51grams (0.25mol) of Iodobenzene in a 1litre three necked round bottom flask followed by adding 208grams (0.82mol) of 30% Peracetic acid drop wise into the flask at a temperature ranging between 15°C-35°C for two hours along with uniform stirring, so as to control drop in temperature. The method further involves mixing the contents in the flask, and incubating the prepared solution for two hours a temperature ranging between 15°C-35°C. The prepared solution is then cooled at a temperature ranging between 0°C-10°C. The slurry is then filtered. The prepared solid is then dried in a dryer, resulting in the production of 72.4 grams & 90% yield of Iodobenzene Diacetate.

EXAMPLE 3
[0041] The method for preparation of Peracetic acid involves addition of 250grams (4.16mol) of acetic acid in a 1litre three necked round bottom flask followed by adding 2.5grams of sulfuric acid along with uniformly stirring the solution. The method further involves adding 115grams (1.69mol) of 50% Hydrogen peroxide drop wise at temperature ranging between 25°C-35°C for 2 hours, so as to control the drop in temperature. The prepared solution is then incubated for 10 hours at a temperature ranging between 25°C-40°C, resulting in the preparation of Peracetic acid.

[0042] The following experimental data should not be construed to limit the scope of the present invention.

EXPERIMENTAL DATA

[0043] Several experimental tests were performed for quality analysis of Iodobenzene diacetate synthesized in the present invention. The standard procedure was followed for performing the tests. It was reported that the Iodobenzene diacetate was in a form of white powder. The melting range of the Iodobenzene diacetate evaluated using a melting point apparatus and was reported to be in a range of 162°C - 163°C. Iodobenzene diacetate was placed inside loss on drying (LOD) oven followed by weighing the Iodobenzene diacetate using weighing balance and the amount of Iodobenzene diacetate lost on drying was reported to be 0.32% by weight of the Iodobenzene diacetate. The concentration of Iodobenzene diacetate was reported to be 99.73% on dried basis using potentiometric titrations.

[0044] Table 1 illustrates several experimental tests and results obtained along with standard limit.

TESTS RESULTS LIMITS
Description White powder [white to off white crystalline powder]
Identification by IR Complies The infrared spectrum of test sample should be concordant with infrared spectrum of the standard.
Melting Range 162°C - 163°C [160°C - 164°C]
Loss on drying 0.32% w/w [NMT 0.5% w/w]
Assay 99.73% on dried basis [NLT 99.0% on dried basis]

Table 1

[0045] FT-IR Spectroscopy of Iodobenzene diacetate synthesized in the present invention was performed.

[0046] Procedure: The procedure for performing FT-IR Spectroscopy involves drying potassium bromide at 120° C followed by cooling potassium bromide; weighing approximately 100mg to 200mg of potassium bromide in to a mortar. Dried potassium bromide was then grounded into fine powder. Approximately 1 mg of the Iodobenzene Diacetate was mixed thoroughly with dried potassium bromide followed by grounding the mixture into fine powder. A small quantity of powdered mixture was put into a pellet making die and converted to pellet by applying force of approximately 10 tons. IR spectrum of the disk was recorded from 4000 cm -1 to 400 cm -1 taking potassium bromide as a reference.

[0047] Analysis: The blank was measured by transferring empty potassium bromide pellet into sample chamber. The sample was placed into sample holder and analyzed using FT/IR-4100 Type-A instrument.

[0048] The FT-IR spectra of Iodobenzene diacetate as shown in Figure 1 which depicts more than 64 bands in the range of 4000 cm-1 to 400 cm-1. Table 1 shows 20 structurally bands identified and assigned out of the 64 bands. The strong and broad bands observed at 3427 cm-1, 3416 cm-1 and 3077 cm-1 were assigned to ? O-H bond stretching, however, the nature is intermolecular, indicating the presence of hydrogen bonding between two successive molecules. The weak shoulder observed at 1714 cm-1 was assigned to ? C=O stretching, however, the nature is dimer, indicating the presence of intermolecular hydrogen bonding. The aromatic nature of molecule was identified by the bands observed at 1644 cm-1, 1625 cm-1, 1572 cm-1 and 683 cm-1. The sharp and strong bands observed at 1644 cm-1, 1625 cm-1, 1572 cm-1 were assigned to ? C=C stretching vibration, indicating unsaturation in the molecule, whereas the band observed at 683 cm-1 confirms the presence the benzene derivative and also confirms the presence of hydrogen bonding between two successive molecules, intermolecular hydrogen bonding, and unsaturation in the molecule. The weak Bands observed at 1273 cm-1 and 1163 cm-1 were assigned to ? C-O bond stretching vibration and confirms ester linkage. The presence of two terminal methyl groups in the structure was confirmed by assigning sharp bands observed at 1472 cm-1 and 1438 cm-1 to ? C-H bending vibrations. Three structurally essential bands were observed at 764cm-1, 683cm-1 and 500cm-1 out of which weak shoulder at 764cm-1 is assigned to ? O-I vibration , band at 683 cm-1 confirms the presence the benzene derivative and sharp band at 500cm-1 is assigned to ? C-I stretching. The assignment of observed bands to a particular type of bond stretching confirms the analyzed sample to be Iodobenzene diacetate.

Sr. No. wavenumber (cm-1) assignments
1 3427 ?-OH (Stretching) Intermolecular
2 3416 ?-OH(Stretching) Intermolecular
3 3059 ?-CH (stretching)
4 3027 ?-CH (stretching)
5 3017 ?-CH (stretching)
6 1714 ?-C=O (stretching) Carboxylic acid (dimer)
7 1644 ?-C=C (Stretching) Conjugated Alkene
8 1625 ?-C=C (Stretching) Cyclic Alkene
9 1572 ?-C=C (Stretching) Cyclic Alkene
10 1472 ?-C-H (bending) (Methyl)
11 1438 ?-C-H (bending) (Methyl)
12 1273 ?-C-O stretching Aromatic ester
13 1164 ?-C-O stretching ester
14 995 ?-C=C (bending) alkene
15 893 ?-C=C (bending) alkene
16 764 ?-O-I
17 745 ?-C-H (bending)
18 683 benzene derivative
19 667 ?-C=C (bending)
20 500 ?-C-I (stretching)

Table 1

[0049] NMR Spectroscopy of Iodobenzene diacetate synthesized in the present invention was performed. Particularly, Proton Nuclear Magnetic Resonance spectra was obtained for Iodobenzene diacetate.

[0050] Procedure: The procedure for performing NMR spectroscopy involves placing approximately 5mg to 25 mg of Iodobenzene diacetate in a secondary vial followed by transferring deuterated chloroform in to the vial containing sample. The solution inside the secondary vial was thoroughly mixed. Tetramethyl Silane (TMS) was used as internal standard.

[0051] Analysis: The sample was transferred to NMR tube using Pasteur pipette. The prepared sample of Iodobenzene diacetate was scanned using JNM-ECZ400S/L1 spectrometer at applied strength of 400MHz, 9.38977 T.

[0052] 1H-NMR spectra of Iodobenzene diacetate as shown in Figure 2 and Figure 3, depicts six peaks at d 2.01ppm, d 7.37ppm, d 7.51 ppm, d 7.60 ppm, d7.85ppm, d 8.09 ppm respectively, out of which peak observed at d2.01ppm was singlet in nature, and peaks observed at d 7.51 ppm, d 7.60 ppm and, d 8.09ppm were multiplets in nature. The below figure shows the arrangement of the protons on benzene ring.
[0053] Table 2 depicts the value of six peaks and at its position on benzene ring. The terminal C-CH3 protons (Ha) present at acetoxy groups are featured at d2.01ppm and appeared as singlet. All six protons of methyl groups are equivalent and therefore coupled to give sharp singlet. The other three peaks appeared as multiplets featuring 5 protons of Ortho, Meta and Para positions (C-H) of benzene ring. The multiplet at d 7.60 ppm features single proton at Para position (Hd) of benzene ring and other two multiplets at d 8.09 ppm and d 7.51 ppm are related to 2 protons at Ortho (Hb)and 2 protons at Meta position (Hc) of benzene ring respectively.

Position integral Pattern Assignment
8.09[ppm] 2 m H (ortho )
7.85[ppm] 0 d J1 = 7.7[Hz]
7.60[ppm] 1 m H (para)
7.51[ppm] 2 m H (meta )
7.37[ppm] 0 t J1 = 7.7[Hz]
2.01[ppm] 6 s CH3
Table 2
[0054] The present invention exhibits a number of advantages:

1. The Iodobenzene diacetate prepared in the present invention is used as a strong oxidizing agent in several industries.
2. The freshly prepared Peracetic acid exhibits 35% stability and enhanced stability.
3. The Iodobenzene diacetate exhibits improved color appearance unlike commercially available pale yellow color.

[0055] While this invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.
, Claims:WE CLAIM:
1. A method for the synthesis of Iodobenzene diacetate, comprising steps of:
(a) adding Peracetic acid (l) drop wise in Iodobenzene (l) within 1.5 to 2 hours in a molar ratio of 1:3.3 and at a temperature ranging between 15?-35?;
(b) stirring uniformly the solution obtained at step (a);
(c) mixing the solution obtained in step (b);
(d) incubating the solution prepared at step (c) for 2 to 4 hours at a temperature ranging between 15? to 35?;
(e) cooling the solution obtained at step (d) at a temperature ranging between 0?-10?, forming a slurry;
(f) filtering the slurry obtained at step (e); and
(g) drying the filtered solid obtained step (f) in a dryer, resulting in the production of Iodobenzene diacetate.

2. The method as claimed in claim 1, wherein the Peracetic acid is in a concentration of 25-40 weight percentage.

3. The method as claimed in claim 1, wherein the Hydrogen peroxide is in a concentration of 25-50 weight percentage.

4. The method as claimed in claim 1, wherein the Iodobenzene diacetate is synthesized in a range of 90% - 92%.

5. The method as claimed in claim 1, wherein the process for preparing Peracetic acid comprises of the following steps:
(a) adding sulphuric acid (l) to acetic acid (l) in a molar ratio of 1:0.006 (acetic acid:sulphuric acid).;
(b) stirring uniformly the solution obtained in step (a);
(c) adding hydrogen peroxide (l) drop wise into the solution obtained in step (b) within 1.5 to 2 hours such that the molar ratio of acetic acid and hydrogen peroxide is 1:0.40 and at a temperature ranging between 25°C-35°C; and
(d) incubating the solution obtained in step (c) for 8 to 10 hours at a temperature ranging between 25°C to 40°C, resulting in preparation of Peracetic acid.

6. The method as claimed in claim 6, wherein the Peracetic acid prepared in the present invention exhibits 35% activity.