Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2000-01-05
2001-07-03
Shippen, Michael L. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S788000
Reexamination Certificate
active
06255538
ABSTRACT:
INTRODUCTION
This invention pertains to a novel process for the preparation of dialkyl aromatic hydroxyl compounds such as dialkylphenols, dialkylbenzenediols, dialkylnaphthols and dialkylnaphthalenediols. More specifically, this invention pertains to a process for the preparation of dialkylbenzenediols, especially 2,5-dialkylhydroquinone, by contacting a benzenediol with an olefin in the presence of a sulfonic acid and sulfuric acid.
BACKGROUND OF THE INVENTION
Many processes are known for the preparation of dialkylphenols, dialkylbenzenediols, naphthols and dialkylnaphthalenediols. Czech Patent CS 111,292 describes the alkylation of 2-methylhydroquinone, 2-tert-butylhydroquinone, and 2-tert-octylhydroquinone with diisobutylene in the presence of concentrated sulfuric acid and an inert solvent such as chloroform or a reactive solvent such as acetic acid or excess diisobutylene. The yields reported are of the order of 35%. See also, J. Pospisil and L. Taimr,
Collect. Czech. Chem. Comm.,
29 (1964), 381-5. British Published Patent Application GB 1,469,896 described a process for the synthesis of a hydroxy-(1,1,3,3-tetramethylbutyl)benzene by the reaction of a hydroxybenzene having one or more hydroxyl groups and optionally substituted, in particular hydroquinone, and a 2,2,4-trimethylpentene, i.e., one of its isomers: &agr;-diisobutylene and &bgr;-diisobutylene, or a mixture of the two, in the presence of highly concentrated sulfuric acid and ethylene glycol. According to this patent, highly concentrated sulfuric acid means a concentration in water that is greater than 90%, preferably in the range of 95±3%.
Czech Patent CS 273,290 discloses the preparation of 2,3-bis-(1,1,3,3-tetramethylbutyl)hydroquinone by the alkylation of hydroquinone with diisobutylene using sulfuric acid as a catalyst in a mixture of methanol and aliphatic hydrocarbons. The yield reported is of the order of 65%. U.S. Pat. No. 3,373,210 describes a process wherein the alkylation is carried out in the presence of methanol and sulfuric acid as catalyst to achieve reported yields of 60%. Japanese Kokai 04-103,550 discloses the preparation of dialkylhydroquinones by treating hydroquinone with an olefin containing 6-30 carbon atoms using a strongly acidic polystyrene sulfonic acid-type cation resins wherein the resin preferably consists of particles having a particle diameter of not greater than 0.2 mm. 2,5-Bis(1,1,3,3-tetramethylbutyl)hydroquinone was prepared in a yield of 81% by the reaction of diisobutylene with hydroquinone at 125° C. for 6 hours in the presence of <0.05 mm diameter particles of a strongly acidic polystyrene sulfonic acid resin. Japanese Kokai 04-103,550 also discloses the preparation of 2,5-bis(1,1,3,3-tetramethylbutyl)hydroquinone in a 40% yield by the reaction of diisobutylene with hydroquinone at 35° C. for 6 hours in the presence of acetic, phosphoric and sulfuric acids. Published PCT Patent Document WO 97/16402 discloses a process for the C-alkylation of a hydroxylated aromatic compound having at least one ortho or para hydrogen atom with respect to the hydroxyl group wherein the hydroxylated aromatic compound is contacted with a strong proton acid and a compound which forms a carbocation in the presence of the acid and in the presence of a solvent consisting of a water alcohol couple. In an example, 2,5-di-tert-octylhydroquinone is prepared by contacting hydroquinone with diisobutylene in the presence of water, methanol and benzenesulfonic acid over a period of 8.5 hours to obtain a reaction yield of 74% with an 88% conversion of the hydroquinone.
BRIEF STATEMENT OF THE INVENTION
We have now discovered an improved process for the preparation of dialkyl aromatic hydroxyl compounds such as dialkylphenols, dialkyl-benzenediols, naphthols and dialkylnaphthalenediols. The present invention provides a process for the preparation of dialkyl aromatic hydroxyl compounds such as benzenediols, especially 2,5-dialkylhydroquinone, which comprises contacting an aromatic hydroxyl compounds with an olefin in the presence of a sulfonic acid and sulfuric acid wherein the sulfonic acid:sulfuric acid molar ratio is in the range of about 0.3:1 to 3:1. Our novel process provides dialkyl aromatic hydroxyl compounds in good yields over shorter reaction periods. The product is of high purity, avoiding complex work-up such as alkali washes, thereby increasing product shelf-life. The product precipitates cleanly from the reaction mixture facilitating application in a continuous reactor system. The reaction proceeds readily in a temperature range which minimizes contaminant build-up and avoids the requirement of specialized pressure equipment. Low cost, readily available catalysts are utilized. No organic alcohol or alkane cosolvent is required beyond the reacting olefin itself. The compounds which may be prepared according to the present invention are useful as antioxidants and stabilizers in a variety of products such as oils and fats and petroleum products and as industrial intermediates for the production of surface active agents, coating materials and plastics.
DETAILED DESCRIPTION OF THE INVENTION
The process of our invention comprises contacting an aromatic hydroxyl compound such as a benzenediol with an olefin in the presence of a sulfonic acid and sulfuric acid wherein the sulfonic acid:sulfuric acid molar ratio is in the range of about 0.3:1 to 3:1 to produce a dialkyl aromatic hydroxyl compound such as a dialkylbenzenediol. The process is particularly valuable for the production of 2,5-dialkylhydroquinones from hydroquinone and will be described herein with particular reference to such hydroquinone compounds.
The olefin reactant employed in the process may contain from 3 to 30 carbon atoms, preferably &agr;-olefins containing from 3 to 12 carbon atoms. Examples include, but are in no way are limited to, isobutylene, isoamylene, 1-hexene, 2-methyl-1-pentene, 2-methyl-2-pentene, 1-octene, diisobutylene, 1-decene, 1-dodecene, 2-dodecene, 1-tetradecene, 2-tetradecene, 1-hexadecene, 1-eicosene, &agr;-pinene, camphene, limonene and styrene. Olefin precursors which dehydrate or in some other way eliminate or rearrange under the reaction conditions to form an olefin also may be employed as the olefin source. However, the olefin-generating feedstock should be chosen judiciously to insure that its reactivity or bulk does not slow the conversion, generate contaminants or otherwise affect detrimentally the desired alkylation reaction. Isobutylene and diisobutylene are particular preferred olefin reactants, e.g., for the production of 2,5-bis(tertiary butyl)hydroquinone and 2,5-bis(1,1,3,3-tetramethylbutyl)hydroquinone. The olefin:aromatic hydroxy compound mole ratio normally should be at least 2:1 and typically is in the range of about 3:1 up to 9:1, preferably about 4:1 to 6:1. Since the reaction mixture contains two distinct phases, the reaction of the olefin with the aromatic hydroxy compound is influenced by a variety of factors. Clearly, as in the case of the formation of 2,5-bis(1,1,3,3-tetramethylbutyl)hydroquinone wherein hydroquinone is reacted with two equivalents of olefin, at least two moles of diisobutylene is required for each mole of hydroquinone. Other factors that can minimize excessive olefin requirements include insuring reasonable stir rates and minimizing olefin side reactions.
The alkylation reaction is carried out in the presence of at least one sulfonic acid and sulfuric acid. The sulfonic acid may be selected from a wide variety of halosulfonic acids and aliphatic, cycloaliphatic and aromatic sulfonic acids. Specific examples of the sulfonic acids include fluorosulfonic acid; chlorosulfonic acid; alkane mono- and di-sulfonic acids containing up to about 6 carbon atoms such as methanesulfonic acid, ethanesulfonic acid, ethanedisulfonic acid and trifluoromethanesulfonic acid; aryl mono- and di-sulfonic acids such as benzenesulfonic acid, toluenesulfonic acid, benzenedisulfonic acid, naphthalenesulfonic acid, napthalenedisulfonic acids, camphorsulfonic acid and xylenesulfonic a
DeBord Sharon Denise
Dougherty Shawn Marie
Maleski Robert Joseph
Blake Michael J.
Eastman Chemical Company
Gwinnell Harry J.
Shippen Michael L.
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