1. A diol functionalized antioxidant which is 2,6-di-tert-butyl-4-(bis(2-hydroxy isopropyl)aminomethyl)phenol.
2. A process for the preparation of diol-functionalized antioxidant of the formula I below:
wherein R1 is tert-butyl and R2 is selected from the group consisting of C1 to C8 linear or branched alkyl, said process comprising dissolving a compound formula III:
wherein R1 is a tertiary butyl group and X is hydrogen in a dry solvent, adding dropwise a solution of bromine in dry carbon tetrachloride or liquid bromine maintaining reaction mixture at a temperature in the range of 80-85\xb0 C. under inert condition for a span of 4-5 hours, cooling the reaction mixture to room temperature and evaporating the solvent to obtain a hindered phenol of formula II in the form of a viscous, pale yellow liquid,
wherein R1 is a tertiary butyl group and X is Br, and dissolving the compound of formula II in an organic solvent, reacting the solution of compound of formula II with a diol of general formula IV:
wherein R2 is selected from the group consisting of C1 to C8 linear or branched alkyl, along with an inorganic mild base under continuous stirring, refluxing the reaction mixture at a temperature in the range of 85-90\xb0 C. for 4-6 hrs to obtain fine crystals of the diol functionalized antioxidant of formula (I).
3. A process as claimed in claim 2 wherein the dry solvent used for dissolving compound of formula III is a chlorinated solvent.
4. A process as claimed in claim 3 wherein the chlorinated solvent is selected from the group consisting of carbon tetrachloride, chloroform, chlorobenzene and dichloromethane.
5. A process as claimed in claim 2 wherein the bromination of compound of formula (III) is carried out using liquid bromine.
6. A process as claimed in claim 2 wherein the organic solvent selected for dissolving the compound of formula II is selected from the group consisting of benzene, toluene, xylene, carbon tetrachloride, dichloromethane and tetrahydrofuran.
7. A process as claimed in 2 wherein the diol is selected from C1 and C3 to C8 linear or branched alkyl ethanolamine.
8. A process as claimed in claim 2 wherein the mild inorganic base is selected from carbonates and bi-carbonates of alkali metals.
9. A process as claimed in claim 8 wherein the carbonates and bicarbonates of alkali metals are selected from the group consisting of potassium carbonate, sodium carbonate, calcium carbonate, sodium bicarbonate and potassium bicarbonate.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A process for preparing benzophenones of the formula I,
where X may be chlorine, hydroxyl, methoxy or C1C6-alkylcarbonyloxy, and Y may be chlorine or bromine, by reacting an acid chloride of the formula II
where X and Y are as defined above with 3,4,5-trimethoxytoluene, which comprises carrying out the reaction in the presence of
a) an aromatic hydrocarbon selected from the group of: chlorobenzene, benzotrifluoride and nitrobenzene as a diluent and
b) from 0.01 to 0.2 mol % of an iron catalyst, based on the acid chloride,
c) at a temperature between 60\xb0 C. and the boiling point of the particular diluent.
2. A process as claimed in claim 1, wherein the diluent used is chlorobenzene.
3. A process as claimed in claim 1 or 2, wherein 3,4,5 -trimethoxytoluene is initially charged, optionally in the particular diluent, and the acid chloride together with the iron catalyst is metered in, optionally in the particular diluent.
4. A process as claimed in claim 1, wherein the hydrochloric acid forming in the reaction is removed from the reaction mixture by stripping using an inert gas stream.
5. A process as claimed in claim 4, wherein the diluent is distilled off toward the end or during the course of the reaction, and the remaining product melt is crystallized in a C1-C6-alcohol.
6. A process as claimed in claim 1, wherein the acid chloride of the formula II is prepared by reacting an acid of the formula III
where X and Y are each as defined above with thionyl chloride or phosgene, optionally in the presence of dimethylformamide, in the same diluent which is also used in the subsequent Friedel-Crafis stage.
7. A process as claimed in claim 6, wherein, after formation of the acid chloride II, at least a portion of the diluent is distilled off with excess thionyl chloride and recycled into the process.
8. A process as claimed in claim 6, wherein the acid of the formula IIIa
is prepared by brominating the compound IV
with elemental bromine in the same diluent which is also used in the two subsequent stages.
9. A process as claimed in claim 8, wherein at least a portion of the diluent and excess bromine is distilled off at the end of the bromination and recycled into the process.
10. A process as claimed in claim 1, wherein the amount of iron catalyst is 0.03 to 0.1 mol %, based upon the acid chloride.
11. A process as claimed in claim 1, wherein the amount of iron catalyst is less than 0.1 mol %, based upon the acid chloride.
12. A process as claimed in claim 1, wherein the diluent used is benzotrifluoride.
13. A process as claimed in claim 1, wherein the diluent used is nitrobenzene.