EP3060539A1 - Use of alkane sulphonic acid for preparing phenolic alcohol - Google Patents

Abstract

The use of alkane sulphonic acid for preparing phenolic alcohol. The invention relates to a use of at least one alkane sulphonic acid for preparing phenolic alcohol by decomposing aryl hydroperoxide, and to a method for preparing phenolic alcohol comprising the following successive steps: -bringing aryl hydroperoxide into reaction in the presence of at least one alkane sulphonic acid, -neutralising the reaction medium, -separating the ketone or the aldehyde, -separating phenolic alcohol by distillation.

Description

 Use of alkane sulfonic acid

 for the preparation of phenolic alcohol

The present invention relates to the use of alkanesulfonic acid for the preparation of phenolic alcohol. The invention also relates to a process for the preparation of phenolic alcohol by decomposition of aryl hydroperoxide.

 The decomposition reaction of cumene hydroperoxide to phenol and acetone has been known for many years. This reaction has the following pattern:

 hydroperoxide phenol acetone

 of cumene

Documents US 2,757,209 and US 2,737,527 dating from 1956 disclose this method of synthesis. In general, cumene hydroperoxide, or the crude of the cumene hydroperoxidation reaction, is reacted with an acid catalyst at a temperature between 40 and 100 ° C. The reaction medium is then cooled and neutralized with a base. The medium is then distilled to first separate the acetone on a first distillation column, then the heavier phenol on a second column, which are the desired products. The acid used is usually a strong acid, usually in the form of a concentrated aqueous solution. The strong acids usually used are sulfuric acid, hydrochloric acid or phosphoric acid which generate, after neutralization of the reaction medium with an aqueous base, sulphates, chlorides or phosphates. Each of these acids has disadvantages, in terms of corrosion, or generation of effluents harmful to the environment, to name only some of these disadvantages.

 Moreover, the presence of these salts (sulphates, chlorides and phosphates) is actually very troublesome in many respects during the purification of the phenol, especially during its subsequent distillation. Indeed, it has been observed that sulphates, chlorides and phosphates are not soluble in the acetone / phenol / water or phenol / water mixture. This low solubility can be detrimental to the conduct of the distillation and the recovery of the purified phenol under conditions of acceptable yield and purity.

 The presence of insoluble compounds in the streams of an industrial distillation plant is highly detrimental in that these insoluble compounds can cause flow disturbances, especially in the distillation column itself, and consequently lead to losses of load, even risk of co-slagging, deposits, etc. In addition, any loss of charge requires greater energy consumption, in particular to operate at a higher temperature, which results in degradations and decompositions of the products, thus causing a loss of quality of the purified phenol and losses of overall distillation yield.

 Improvements in this method have been proposed in the prior art.

 The use of trichloromethanesulfonic acid resulting in a lower amount of used acid, a lowering of the reaction temperature and better yields is described in GB 803, 480.

 More recently, the use of organic base to neutralize the reaction medium has been described in US 6,201,157.

 Document US 2003/0088 129 describes a two-step process involving two distinct temperature stages.

The use of solid acid catalysts, such as montmorillonite, cation exchange resins, catalysts Alumina-silica type has also been envisaged in JP2007-099746.

 The inventors have found that the use of one or more alkanesulphonic acids leads to a clear improvement of the phenol preparation process.

 First, compared to sulfuric acid, the alkanesulfonic acid is not desiccant. Indeed, in the case of the phenol synthesis, it has been observed that the content of by-products, especially acetone, such as mesityl oxide is lower. As a result, a gain in selectivity and yield is observed.

 In addition, the neutralization of the reaction medium results in the formation of insoluble salts, such as sodium or potassium sulphates, which need to be removed generally by filtration, before carrying out the distillation. The use of alkanesulfonic acid has the advantage of leading to the formation of organic salts which are more soluble in the reaction medium. As a result, the filtration step becomes unnecessary. In addition, the risks of clogging due to the presence of salts are avoided. Therefore, on the industrial level, the use of alkanesulfonic acid allows a gain in productivity by simplifying the process.

 Thus, a first object of the present invention is the use of at least one alkane-sulfonic acid for the preparation of phenolic alcohol by decomposition of aryl hydroperoxide and preferably the use of at least one acid alkanesulfonic acid for the preparation of phenolic alcohol and ketone or aldehyde by decomposition of aryl hydroperoxide.

 Another object is to provide an improved process for the preparation of phenolic alcohol comprising a step of decomposing aryl hydroperoxide in the presence of at least one alkane sulfonic acid.

 Still other objects will become apparent from the following description of the present invention.

On the other hand, any range of values designated by the expression "between a and b" represents the range of values from more than a to less than b (i.e., bounds a and b excluded), while any range of values designated by the expression "from a to b" means the range of values from a to b (c) that is, including terminals a and b).

 use

 The present invention relates to the use of at least one alkanesulfonic acid for the preparation of phenolic alcohol by decomposition of aryl hydroperoxide.

 Aryl hydroperoxide

 For the purposes of the present invention, aryl hydroperoxides are understood to mean compounds with aromatic groups whose hydroperoxide function is carried by a carbon atom positioned in the alpha position of the aromatic ring.

 Aromatic means aromatic rings having from 6 to 14 carbon atoms, preferably from 6 to 10 carbon atoms (inclusive) and typically phenyl and naphthyl.

 The aryl hydroperoxides according to the present invention are preferably of the following general formula (or structure) (I):

 in which

the groups R 1 and R ₂ denote, independently of one another, a hydrogen atom, a C 1 to C ₁₈ , preferably C 1 to C ₁₀ , more preferably C 1 to C ₆ , linear alkyl radical; or branched, a C ₆ to C ₁₄ aryl radical, preferably a C ₆ to C ₁₀ aryl radical, and typically phenyl and naphthyl,

the groups R ₃ to R ₇ denote, independently of one another, a hydrogen atom, a C 1 -C ₁₈ alkyl radical, preferably Ci -C _10, more preferably C, to C ₆ linear or branched, a halogen atom, in particular fluorine, chlorine, bromine and iodine, a radical -N0 _2, -CN radical, a substituted alkyl radical by one or more halogen atoms, a C ₆ to C ₁₂ aryl radical,

two adjacent groups R ₃ to R ₇ may together form one or more aliphatic or aromatic rings.

For example, R ₃ and R ₄ may together form an aromatic ring of 6 carbon atoms then leading to a naphthalene hydroperoxide. R ₃ and R ₄ can also together form an aromatic bicycle with 12 carbon atoms, thus leading to an anthracene hydroperoxide.

Preferably, the groups R 1 and R ₂ are chosen from a hydrogen atom, a methyl, an ethyl, an n-propyl, an iso-propyl, a n-butyl, an isobutyl or a tert-butyl.

Preferably, the groups R ₃ to R ₇ are chosen from a hydrogen atom, a methyl, an ethyl, an n-propyl, an iso-propyl, an n-butyl, an isobutyl or a tert-butyl, a chlorine atom, a fluorine atom, a bromine atom, a phenyl radical.

 According to a preferred embodiment, the group R 1 in the compound of formula (I) does not represent the hydrogen atom.

According to another preferred embodiment, the group R ₂ in the compound of formula (I) does not represent the hydrogen atom.

According to yet another preferred embodiment, the groups R 1 and R ₂ in the compound of formula (I) do not denote a hydrogen atom.

Preferably, the aryl hydroperoxide is chosen from cumyl hydroperoxide, butylbenzene hydroperoxide, ethylisopropylbenzene hydroperoxide, (propyl) naphthalene hydroperoxide, diisopropylbenzene hydroperoxide and hydroperoxide. sec-butylbenzene hydroperoxide, para-ethyl-iso-propylbenzene hydroperoxide and α-z ^{'so-propylnaphtalène,} preferably cumyl hydroperoxide.

As a result, the decomposition in an acidic medium of this aryl hydroperoxide of formula (I) makes it possible to lead to formation of phenolic alcohol and ketone or aldehyde according to the nature of the groups R 1 and R ₂ and according to the following reaction scheme:

the groups R 1 to R ₇ being identical to those described above.

Thus, by phenolic alcohol is meant in the sense of the present invention phenol and phenols bearing substituents R ₃ to R ₇ .

The compound of structure R ₂ C (= O) R 1 is hereinafter referred to as the co-product. It can be a ketone or an aldehyde according to whether R 1 and / or R ₂ represent (nt) a hydrogen atom.

 Preferably, cumyl hydroperoxide is used. S decomposition in acidic medium leads to the formation of phenol and acetone.

 Alkane sulfonic acid

 The decomposition of aryl hydroperoxide into alcohols is most often carried out in an acid medium, or at least in the presence of acid (s), and preferably in the presence of an aqueous solution of at least an alkanesulfonic acid.

 In the present invention, the term "alkanesulfonic acid" means the acids of the following general formula (II):

(II) R-S0 ₃ H,

 in which the group R represents a saturated or unsaturated hydrocarbon chain, linear or branched having from 1 to 6 and preferably from 1 to 4 carbon atoms.

 The compounds of formula (II) for which R represents a saturated, linear or branched hydrocarbon-based chain containing from 1 to 6 and preferably from 1 to 4 carbon atoms are preferred.

The alkane-sulphonic acids that can be used in the context of the present invention are very particularly preferred. selected from methanesulfonic acid, ethanesulfonic acid, n-propanesulfonic acid, isopropane sulfonic acid, n-butanesulfonic acid, iso-butane sulphonic acid, sec-butanesulfonic acid, tert-butanesulphonic acid, and mixtures of two or more of them in all proportions. The pKa of the alkanesulfonic acids are all less than zero.

According to a very particularly preferred embodiment, the alkane-sulphonic acid used in the context of the present invention is methanesulfonic acid or ethanesulphonic acid, and it is most preferably the acid used. methanesulfonic acid of formula CH ₃ SO ₃ H.

 Any type of formulation comprising at least one alkanesulfonic acid may be suitable. It is possible to use at least one alkanesulphonic acid in anhydrous form or in the form of an aqueous solution. As a rule, the formulation comprises from 1% to 100% by weight of alkane-sulphonic acid (s), preferably from 1% to 99% by weight, more preferably from 1% to 95% by weight, in general. from 5% to 95% by weight and more generally from 5% to 90% by weight, in particular from 10% to 80% by weight of alkanesulphonic acid, and more particularly from 15% to 75% by weight, 100% supplement usually consisting of water. It goes without saying that when the formulation comprises 100% by weight of alkane-sulphonic acid (s), it is meant that the alkane-sulphonic acid (s) are used pure, more precisely are used alone, without addition of other formulation components.

The formulation also comprises the possible presence of one or more additives well known to those skilled in the art and by way of nonlimiting examples chosen from solvents, hydrotropic or solubilizing agents, biocides, disinfectants, rheological agents, preservatives, surfactants and the like. active ingredients, organic or inorganic acids (eg sulfuric, phosphoric, nitric, sulfamic, acetic, citric, formic, acetic, glycolic, oxalic and others), foaming agents, antifoam agents, anti-gels (for example ethylene glycol, propylene glycol, and the like) ), dyes, perfumes, anti-corrosion additives, UV protectors and other additives known to those skilled in the art, alone or as a mixture of two or more of them in all proportions.

 The formulation is for example an aqueous formulation which can be prepared as a concentrated mixture which is diluted by the end user. Alternatively, the formulation may also be a ready-to-use formulation, i.e., it does not need to be diluted. It is possible, for example, to use methanesulphonic acid in aqueous solution sold by Arkema, for example an aqueous solution of methanesulphonic acid at 70% by weight in water, or even methanesulphonic acid. Anhydrous sulfonic acid or AMSA, acronym for "anhydrous methane sulphonic acid" in English.

 According to a preferred embodiment, the present invention relates to the use, for the preparation of phenol by decomposition of cumyl hydroperoxide in the presence of methanesulfonic acid (AMS) in all possible concentrations, ranging from AMSA ( AMS anhydrous) at concentrations of the order of 5% by weight of AMS in water, and in particular the aqueous solutions of AMS at 70% by weight in water, marketed by the company ARKEMA.

 It is of course possible to use a mixture of at least one alkane-sulphonic acid of formula (II), as just defined, in association with one or more acids (organic and / or inorganic), in all proportions.

 However, it is preferred to use an alkanesulfonic acid or a mixture of alkanesulfonic acids alone.

 Process

 The invention also relates to a process for preparing phenolic alcohol, comprising a step of decomposing aryl hydroperoxide in the presence of alkanesulfonic acid.

 More particularly, the method according to the invention comprises the following steps:

reacting aryl hydroperoxide in the presence of at least one alkanesulphonic acid, -neutralization of the reaction medium,

 separation by distillation of the co-product, that is to say the ketone or the aldehyde, then

 -separation by distillation of the phenolic alcohol.

 The reagent of the process according to the invention is aryl hydroperoxide, as described above and more particularly cumyl hydroperoxide.

 It can be used pure. It can also be present in a crude peroxidation reaction.

 For example, for the case of cumyl hydroperoxide, the reaction crude of the hydroperoxidation step may comprise benzene derivatives, such as cumene, dimethylphenylcarbinol, dicumyl, dicumyl peroxide, acetophenone.

 The acidic catalyst comprises at least one alkanesulfonic acid as described above and advantageously methanesulfonic acid. It can be used pure or in aqueous solution.

 Preferably, the content of alkane-sulphonic acid (s) is between 100 ppm and 50,000 ppm, more particularly between 200 and 8,000 ppm, relative to the aryl peroxide (s) introduced. .

 The amount of alkane-sulphonic acid (s) introduced into the reaction crude may therefore vary according to the reagent present, namely the pure aryl hydroperoxide or the reaction crude of the hydroperoxidation. Those skilled in the art will be able to adapt the amount of alkane-sulphonic acid (s) to be added to the reaction crude depending also on the concentration of said acid (s). According to one embodiment, the acid is introduced either into the stream of the aryl hydroperoxide or into the stream of solvent, which solvent is generally added as a diluent because the reaction is very exothermic. This reaction is generally, and most often, carried out in the liquid phase.

The reaction solvent may be any organic solvent or mixture of organic solvents, optionally with water (hydro-organic solvents) known to those skilled in the art and suitable for this type of reaction, and in particular one or more solvents ( s) organic (s) polar (s), protic (s) or aprotic (s), preferably polar (s) and aprotic (s). Ketones, and especially acetone (dimethylketone), are particularly suitable for carrying out the process according to the present invention.

 The reaction temperature is generally between

50 ° C and 150 ° C. Those skilled in the art will be able to adapt the reaction temperature according to the reactants present, the catalyst content and the concentration of the reactants in the medium.

 Similarly, the duration of the reaction will depend on the above parameters.

 According to one embodiment, the aryl hydroperoxide, pure or in the crude reaction is reacted, optionally but preferably in a solvent medium, with at least one alkanesulfonic acid, as described above.

 The process then comprises a step of neutralizing the reaction medium.

 The neutralization of the acid phase is not without consequences on the nature of the medium which is intended to be distilled. Indeed, during this neutralization step, the acidic species are neutralized in the form of salts.

 The inventors have surprisingly discovered that the different alkali metal and / or alkaline earth metal salts, present in this phase, thus neutralized and intended to be distilled, are more soluble in the phenol / ketone / water or phenol mixture. water, when the neutralization has been carried out on a medium previously acidified with at least one alkanesulfonic acid, in particular methanesulphonic acid, whereas the same salts are less soluble when the acidification has It has been carried out with other acids, especially strong mineral acids commonly used in the field, such as sulfuric, hydrochloric or phosphoric acids.

In addition, the aforementioned salts in the form of alkanesulfonates, preferably methanesulfonates, have proved more soluble than sulphates, chlorides and other phosphates in the phenol / ketone mixture. (or aldehyde) / water or phenol / water (once ketone or distilled aldehyde).

 This is all the more remarkable in that the distillation operations are very sensitive to solid impurities present in the distillation plants and in particular in the distillation boiler (or foot) but also in the distillation columns. However, phenol / ketone / water (or phenol / water) concentration gradients and temperatures vary along the distillation columns.

 Acidification with at least one alkanesulphonic acid, and preferably with methanesulfonic acid, has the advantage of improving the solubility of the salts, especially the sodium and / or potassium salts present in the phenol mixture. / ketone / water (or phenol / water).

 This advantage of the alkanesulphonic acid relative to the other strong acids currently in use makes it possible to avoid the formation of solid deposits which can cause flow disturbances, especially in the distillation column itself and consequently lead to loss of loads, or even risks of clogging, deposits, etc.

 In addition, this greater solubility of the salts of alkanesulfonic acids in the phase comprising phenol, and in particular in the boiler, at the bottom of the column, makes it possible to continue the distillation operation to a more advanced degree. , and thus further improve the distillation yield. Another advantage related to a better solubility of the salts in the phenol is the reduction of the risk of coagulation in the bottom of the column, where the phenol / water mixtures are the most concentrated in phenol. The overall yield of the distillation is thus greatly improved.

The greater solubility of the salts in the medium to be distilled can also make it possible to envisage a significant reduction in the number of theoretical plates of the column, and consequently the physical height of the column, as well as substantially reducing the quantity of column. energy used for the total distillation of phenolic alcohol. Yet another advantage, related to the acidification by at least one alkanesulphonic acid of the crude reaction containing the phenolic alcohol, is that the solids deposits are less important and therefore the shutdown periods for cleaning. Distillation plants are further spaced over time.

 Yet another advantage is that the alkanesulfonates, and more particularly the methanesulfonates, are very soluble in an aqueous medium and are biodegradable. The installations are therefore easier to clean, and as a result require much smaller volumes of water, and the cleaning effluents are more respectful of the environment.

 This neutralization implements basic substances. Preferably, the bases used are mineral species which are inert with respect to the species present in the reaction medium. More particularly, the bases are selected from alkali metal or alkaline earth metal hydroxides, such as sodium or potassium hydroxide, alkali metal or alkaline earth metal carbonates. These bases are most often and advantageously used in aqueous solution. Preferably, sodium hydroxide is used.

 In cases where insoluble salts are present, a filtration step may be contemplated, although this is not a preferred variant of the process of the invention. These insolubles can in particular come from the hydroperoxidation reaction crude.

 Preferably, a settling step is carried out in order to separate the aqueous phase from the neutralization solution and the organic phase containing the species to be purified.

 The phenolic alcohol present in the neutralized reaction medium is then separated from the residual water and by-product. This separation can be carried out according to any method known to those skilled in the art and, preferably, by distillation. During this distillation operation, the co-product is first distilled, then water, and finally phenolic alcohol.

The distillation of the phenolic alcohol is generally carried out under reduced pressure, generally under vacuum (for example at 280 mm Hg, 37.33 kPa) with boiler at 170 ° C. and distillation of the phenol at about 150 ° C.

 This process is characterized in that it uses at least one alkanesulfonic acid and more preferably methanesulfonic acid. The use of this acid has the advantage of being less corrosive, biodegradable, respectful of the environment, and also has the advantage of solubilizing the salts present in the reaction medium allowing the conduct of the final distillation of the acid. phenolic alcohol under more economical conditions, as explained above in the description.

 Preferably, the method according to the invention comprises the following steps:

 reacting cumyl hydroperoxide in the presence of at least one alkanesulfonic acid, preferably methanesulfonic acid,

 neutralization of the reaction medium,

 - separation by distillation of acetone, and

 - Distillation of the phenol by distillation. The following examples illustrate the present invention without however limiting its scope defined by the following claims.

EXAMPLES: Comparison of solubilities

 In a 50 ml trico l equipped with a condenser, a thermometer and a magnetic stirrer, 25 g of solvent to be tested are introduced. The solvent is brought to the desired temperature, and then the alkane sulphonic acid salt is added in portions until there is a cloudiness signifying the saturation of the medium.

 The solubility is calculated as follows:

 % solubility salt = m / (m + M) x 100

with m = mass of dissolved salt, M = mass of solvent

The results are shown in the tables below. 1. Solubility of salts in a mixture by weight: phenol / acetone / water (50/50/5):

 A first measurement is made at 20 ° C at atmospheric pressure, then a second measurement is performed at 60 ° C. The point at 60 ° C makes it possible to evaluate the solubility of the species in the boiler during the distillation of acetone.

 1. 1 Salts of potassium

 Table 1

In this mixture, at 20 ° C and 60 ° C, potassium methanesulfonate is more than 6.7 times more soluble than potassium sulfate.

 1 .2 Sodium salts

 Table 2

In this mixture, at 60 ° C, sodium methanesulfonate is more than 2.4 times more soluble than sodium sulfate. 2. Solubility of salts in a mixture by weight: phenol / water (95/5):

A first measurement is performed at 55 ° C at atmospheric pressure, then a second measurement is performed at 100 ° C. The point at 100 ° C makes it possible to evaluate the solubility of the species in the boiler during the distillation of the water.

 2. 1 Salts of potassium

 Table 3

In this mixture, at 20 ° C and 60 ° C, potassium methanesulfonate is respectively 15 and 8 times more soluble than potassium sulfate.

 2.2 Sodium salts

 Table 4

In this mixture, at 20 ° C and 60 ° C, sodium methanesulfonate is more than 2 times more soluble than sodium sulfate.

Claims

1. Use of at least one alkanesulfonic acid for the preparation of phenolic alcohol and ketone or aldehyde by decomposition of aryl hydroperoxide.  2. Use according to claim 1, characterized in that the aryl hydroperoxide has the following structure (I):  (I)  in which the groups R 1 and R ₂ denote, independently of one another, a hydrogen atom, a C 1 to C ₁₈ , preferably C 1 to C ₁₀ , more preferably C 1 to C ₆ , linear alkyl radical; or branched, a C ₆ to C ₁₄ , preferably C ₆ to C ₁₀ , aryl radical and typically phenyl and naphthyl, the groups R ₃ to R ₇ denote, independently of each other, a hydrogen atom, a C 1 to C ₁₈ , preferably C 1 to C ₁₀ , more preferably C 1 to C ₆ , linear or branched alkyl radical; a halogen atom, in particular fluorine, chlorine, bromine and iodine, an -NO ₂ radical, a -CN radical, an alkyl radical substituted with one or more halogen atoms or a C ₆ -C ₁₂ aryl radical; two adjacent groups R ₃ to R ₇ may together form one or more aliphatic or aromatic rings. 3. Use according to claim 2, characterized in that the groups R 1 and R ₂ do not denote a hydrogen atom. 4. Use according to claim 2 or 3, characterized in that the aryl hydroperoxide is cumyl hydroperoxide.  5. Use according to any one of claims 1 to 4, characterized in that the alkanesulfonic acid corresponds to the following general formula (II): (II) R-S0 ₃ H,  in which the group R represents a saturated or unsaturated hydrocarbon chain, linear or branched, having from 1 to 6 and preferably from 1 to 4 carbon atoms.  6. Use according to claim 5, characterized in that the alkanesulfonic acid is methanesulfonic acid (CH3SO3H).  7. Use according to any one of the preceding claims, characterized in that the alkanesulfonic acid is in anhydrous form or in the form of an aqueous solution comprising from 5% to 90% by weight, in particular from 10% to 80% by weight. > by weight of sulphonic acid, and more particularly from 15% to 75% by weight, the 100% complement consisting of water.  8. A process for the preparation of phenolic alcohol comprising the following successive steps:  reacting aryl hydroperoxide in the presence of at least one alkanesulphonic acid,  -neutralization of the reaction medium,  -separation by distillation of the ketone or aldehyde, - separation by distillation of the phenolic alcohol.  The process of claim 8, wherein the aryl hydroperoxide is cumyl hydroperoxide.  The process of claim 8 or 9 wherein the alkanesulfonic acid is methanesulfonic acid.