DE1668942A1 - Alkylation process - Google Patents

Description

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Monsanto Chemicals Limited, London, S.W.1

date

"Alkylation process"

This invention relates to an alkylation process and in particular a process for the preparation of alkylated bis (mienols) ♦

Materials of this type are used to effect oxidation inhibition organic materials, for example oils, plastics and rubber, are known. The class of alkylated bis (phenols) include members that are solids

Gase Ho. B-518

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and others who, under normal atmospheric conditions, Liquids are. Although there is no general correlation between the effectiveness of an alkylated bis- (phenol) as an antioxidant · and its physical. State at atmospheric temperatures is preferred the rubber industry often uses solid rather than liquid additives in the manufacture of theirs because of the handling Products.

The alkylated alkylidenebis (phenols) form an important group of the alkylated bis (phenols), but potentially The cheapest route to these compounds, namely the direct alkylation of bis (phenols), was previously for their production solid products are not available because under the conventional alkylation conditions liquid mixtures of Compounds with different degrees of alkylation are obtained. It has now been found that when used a certain reaction medium alkylidenebis (phenols) can be alkylated to form, from any bisphenol) , a product that consists largely of the monoalkylated bis (phenol), which in many cases is found in ordinary Temperatures is a solid.

The process according to the invention is used to produce an alkylidene bis (phenol), an alkylidenebis (phenol) having at least one ortho or para position unsubstituted to the phenolic hydroxyl group and free 109839/17 83

contains from tertiary alkyl groups in such ortho and para positions is reacted with an alkylating agent, wherein aqueous sulfuric acid, at least 50 wt.% H ^ ^ UEO is used as Keaktionsmedium to form a mono-alkylated derivative of alkylidenebis (phenol) as Main component of the product.

Under the above restrictions, the phenolic nucleus can be substituted or unsubstituted, so that the Process, for example, for the introduction of a further alkyl group in the phenol nucleus, in which an alkyl group already exists, can be used.

The process is particularly useful for the alkylation of 4,4 * -alkylidenebis (phenols) of the general formula:

wherein R is a hydrogen atom or an alkyl group with from 1 to 3 carbon atoms and the radicals R ¹ and R ¹ 'each an alkyl group with from 1 to 3 carbon atoms, for example 4,4'-isopropylidenebis (phenol) (bisphenol A) and 4, 4 ^l -Isopropylidenbis (2-methylphenol) is.

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The optimal alkylation conditions vary according to the particular alkylidenebis (phenol) that is to be alkylated. In the case of, for example, 4,4'-isopropylidene bis (phenol), the acid concentration is preferably in the range of 55 to 65 wt. #, And the (temperature at which the alkylation is carried out is preferably particularly preferably from 35 to 5O ⁰ G acid concentrations of 5 NC to 62 wt.% and (temperatures of from 4-0 to 45 ° C. Similar conditions can in the alkylation of 4,4'-isopropylidenebis (2-methylphenol) can be used.

The alkylating agent used in the process of the invention is preferably an olefin, but it can optionally, for example, the corresponding alcohol or the Halide, for example an alcohol or halide can be used, which the olefin by dehydration or respectively Can form dehydrohalogenation. The alkylating agent can be straight, branched or cyclic Chain, usually having from 5 to 12 carbon atoms contains.

Examples of suitable alkylating agents include i-ropylene, Isobutylene, 2-diethylbutene-1,2-methyl-2-butene, cyclohexene, 1-I "iethyl eye lohexen, di-isobutene, ötyrol, - 1-topylenetrimer and -tetramer, isopropanol, t-butanol, t-jimylalkoiiol, cyclohexanol, I-methylcyclohexanol, isopropyl chloride, t ~ .tiutyl-

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chloride, t-Amylchloric !, honochlorocyclohexane, i-methyl-2-chloro-cyclohexane and the compounds formed by substituting bromine for chlorine where appropriate will. The preferred alkylating agent is an isoolefin and especially isobutylene.

Although the product obtained by the process according to the invention is largely the monoalkylated derivative of alkylidenebis (phenol) it is usually necessary to obtain good yields, more than 1 mole of alkylating agent to use alkylidenebis (phenol) per hol. The yield of mono-alkylated product is higher if, for example 3 moles of alkylating agent can be used instead of 1.5 moles, but above 3 moles of alkylating agent per mole Alkylidenebis (phenol) the increase in yield is significantly less and there is generally no benefit in Use of more than 3 »5 moles of alkylating agent. In general the preferred amount of alkylating agent is in the range of 2.5 to 3-5 moles per mole of alkylidenebis (phenol). The amount of heat in relation to the quantity of alkylidenebis (phenol) to be alkylated is not critical, the minimum amount being determined by the need for a stirrable mixture, while the use of larger amounts than necessary for economic reasons Greens is avoided. The weight of the action mode canoe, for example, in the area of a quantity

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lie, which is approximately equal to the weight of alkylidene bis (phenol) to a 10-fold amount of that weight, and in practice is a 2- to 8-fold Plenge, f 5, in particular, a 3- to ^a che amount of weight des alkylidenebis (phenol) is usually preferred.

After the reaction of the alkylating agent with the bis (phenol) has ended, the solid product is released from the reaction mixture separated and treated to remove traces of acid. This is done simply by ashing the product first with water, then with saturated iatrium carbonate solution and then again with water.

According to a further object of the invention, an alkylidenebis (phenol), which is intended for alkylation, formed by the process described above itself by condensation of a phenol with a ketone in a reaction medium, which is an aqueous sulfuric acid which has at least the concentration of sulfuric acid, which is required in the reaction medium for the alkylation process. The alkylidenebis (phenol) does not have to be off isolated from the reaction medium in which it is formed; it is only necessary that the mixture be diluted with water should be to form a sulfuric acid solution of suitable strength for the alkylation reaction.

The AllcyiidenoitKphenole), which in this. «Is produced

include those that are available by the condensation of phenol, o-cresol, or 2-ethylphenol 2n-propylphenol with ketones of the general formula:

GO - Jfci

wherein the radicals R ¹ and H ″ have the same meaning as in the above formula for alkylidenebis (phenols). Examples of such ketones are acetone and ethyl ethyl ketone.

It has generally been found that the optimum concentration of sulfuric acid for the condensation reaction is higher than the optimum for the alkylation reaction. The former is usually in Bereicn of 70 to 75 wt. P bchwefelsäure. The lower limit for this concentration is of course the same as the lower limit for the concentration of the aqueous oulfuric acid reaction medium in the alkylation process (taking into account the water formed in the condensation process) while the upper useful limit is normally about ÖO / y.

In practice, the condensation of the phenol and ketone is usually carried out at a temperature of 30 to 50 ° 0, where is aerei.cn of Jj'o to 4-3 ° 0 preferred. It is customary to use essentially equivalent cheeks i-henol and ketone, that is, two holar parts of the former to one of the latter. Condensation is preferred

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wisely in the presence of a catalytic amount of an organic Thio compound, for example thioglycolic acid or mercaptopropionic acid, carried out.

The invention is illustrated by the following examples.

example 1

This example describes the alkylation of 4,4'-isopropylidenebis (phenol) using isobutylene as the alkylating agent.

A 250 ecm three-necked flask was fitted with a Stirrer, a thermometer and a three-way stopcock connected to a vacuum and an isobutylene feed. The latter was measured by water displacement as in a conventional hydrogenation device.

59 cc of water were placed in the flask, followed by 98 cc sulfuric acid. 25 "5 g of 4,4'-isopropylidene bis (phenol) of sulfuric acid were added at a temperature not exceeding 50 ⁰ C. The flask was vented using a water pump and then connected to the isobutylene feed. After heating the mixture of sulfuric acid and bis (phenol) to 45 ° C, isobutylene was added until a total of 8800 ecm was absorbed, the process between 5 and 4 1/2

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•. It lasted. The temperature was kept at 45 ° 0 during this time. The mixture was then stirred for 2 hours at 4-5 ⁰ O, cooled, filtered and washed with 50 cc of water, with two 50 cc amounts of saturated bicarbonate solution and finally with 50 cc water. The product was a free-flowing cream-colored powder after drying at approximately 60 ^{0 O under vacuum.} In a number of runs using the same amounts of starting materials, yields of 29.7 to 33.1 g have been obtained. A typical product had a melting range of from 134 to 154- ⁰ G by gas chromatography and was determined the following composition:

2-tert- ± sutyl-4,4 ^! -isopropylidenebis (phenol) 65 2,2'-di-tert-butyl-4,4'-isopropylidenebis (phenol) 6-10 $ 2,6-di-tert-butyl-4,4'-isopropylidenebis (phenol) 2 -4 ^ 6 2,6,2 ^l -tri-tert-l3utyl-4,4'-isobutylidenebis (phenol) 1- 3 #

There were also small amounts of di- and tri-tert-butylphenol and unreacted 4,4'-isopropylidenebis (phenol) is present.

Example 2

This example describes the alkylation of 4,4'-isopropylidenebis (2-methylphenol) with isobutylene.

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Using the apparatus described in Example 1, isobutylene was passed through a stirred suspension of 20 g 4,4 -'- Isopropylidenebis (2-methylphenol) in 80 g 6Q # iger (wt.) Sulfuric acid passed at a 'temperature of 4-5 ° C until . after 1 3/4 hours, 3.75 liters was absorbed. The procedure the procedure used in Example 1 to isolate the product was essentially the same. The alkylated 4-, 4 -'-Isopropylidenebis (2-niethylphenol) turned out to be leather colored obtained colored powder weighing 21.2 g.

Example 3

This example describes the preparation of a t-butylated 4,4'-isopropylidenebis (phenol) using Phenol, acetone and isobutylene as starting materials.

A mixture of 20.9 g phenol, 0.1 ecm acetone, 0.33 g 85 ^ -iger thioglycolic acid and 0.66 ecm toluene was with at a uniform rate, with stirring, to 150 g of 72.5% strength by weight sulfuric acid over a period of Added 1 hour. The temperature became Dei 40 to 42 ° G during the addition and the subsequent 1 1/2 hours held. At this point a further 0.5 ecm of acetone was added and the reaction mixture was then heated at 40 ° G for held for another 1 1/2 hours.

The reaction mixture was then diluted with 32 ecm of water, whereby a sulfuric acid concentration of 60 wt.

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received. The addition of isobutylene and isolation of the product was carried out in essentially the same manner as in FIG Example 1 described, carried out. In different processes one obtained varying yields of 29 | 4- to 32.9 g « The physical properties and compositions did not differ significantly from the product that according to the procedure described in Example 1 was obtained.

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Claims (1)

Claim e: 1. A process for the preparation of monoalkylated derivatives of alkylidenebis (phenols), characterized in that an alkylidenebis (phenol) which has at least one unsubstituted ortho or para position to a phenolic hydroxyl group and in such ortho or para positions is free from tertiary alkyl groups is reacted with an alkylating agent, using aqueous sulfuric acid which contains at least 50 wt.% H ₂ SO ^ as reaction medium. 2. The method according to claim 1, characterized in that the amount of alkylating agent used is more than 1 mole but not more than 3.5 moles per mole of alkylidenebis (phenol). 3 · Method according to one of claims 1 and 2, characterized characterized in that the alkylating agent is an olefin having from 3 to 12 carbon atoms per molecule. ^. Process according to claim 3 _S, characterized in that the olefin isobutylene, 2-methylbutene-1 or 2-methylbutene 2 is. 5. The method according to any one of claims 1 to ¹ J ₅ characterized - 13 1 0 9 8 3 9/1783 indicates that the alkylidenebis (phenol) is a 4,4'-alkylide enbis (phenol) of the general formula wherein each R is a hydrogen atom or an alkyl group having from 1 to 3 carbon atoms and the radicals R ¹ and R "are each an alkyl group having from 1 to 3 carbon atoms. 6. A process for the preparation of a product which contains a larger proportion of mono-alkylated 4,4 ^f -isopropylidenebis (phenol), characterized in that 4 | 4'-isopropylidenebis (phenol) with an alkylating agent at a temperature of 35 to 50 ⁰ G using aqueous sulfuric acid, which of 55 to 65 wt. $ HgSO . ala reaction medium contains, is reacted, the amount of alkylating agent introduced into the reaction medium being more than 1 mol per mol of 4 _f 4 ^f ~ propylidenebia (phenol), 7 «Method according to claim 6, characterized in that the temperature in the range from 40 to 45 ° 0 and the sulfuric acid concentration is in the range of 58 to 62 wt. -14- 109839/1783 16689A2 8. The method according to any one of claims 6 and 7, characterized in that that the alkylating agent is an olefin with is from 3 to 12 carbon atoms per molecule. 9. The method according to any one of claims 6 to 8, characterized in that that the alkylating agent isobutylene, 2-methylbutene-1 or 2-methylbutene-2. 10. The method according to any one of claims 6 to 9, characterized in that that the amount of alkylating agent introduced into the reaction mixture is 2.5 to 3 »5 ttol per half of 4,4'-isopropylidenebis (phenol) is. 11. The method according to any one of claims 6 to 10, characterized in that the weight of the Heaktionsmediums from 3 to 5 times the weight of 4,4'-isopropylidenebis (phenol) is. 12 .. The method according to any one of claims 1 to 9, characterized in that the alkylidenebis (phenol) by itself the condensation of a phenol with a ketone is formed in a reaction medium, the reaction medium is an aqueous sulfuric acid that has at least the concentration which contains sulfuric acid, which is required in the reaction medium for the alkylation process. -15- 109839/1783 13. Process for the alkylation of an alkylidenebis (phenol) essentially as described in one of Examples 1 to 5. 14. Alkylated alkylidenebis (phenol), if it is after a Process according to any one of claims 1 to 9 »12 and 13 was obtained. 15. Alkylated 4,4'-isopropylidenebis (phenol), if it is according to a method according to one of claims 10 and 11 was obtained. 3 9/1783