DE2253963C3 - Process for the production of lactones - Google Patents

Description

in which R denotes an alkyl, alkenyl or aralkyl radical and the radicals optionally one or contain several other substituents, in an inert diluent, among essentially anhydrous conditions in the presence of a catalyst, characterized in that the reaction at a temperature between 120 and 200 ° C in the presence of 0.1 to 20 mol percent, based on the cyclic ketone, metaboric acid, its anhydride or one of its esters the general formula

IR ₁ -OB = O) _n

in which R ₁ denotes an alkyl, aryl, alkaryl or aralkyl radical and each of the radicals optionally contain _{one or more other substituents J5} and η denotes an integer 1 or 3.

The present invention relates to a method / ur production of lactones by reacting a cyclic ketone with 5 or 6 carbon atoms with a hydroperoxide of the general formula

ROOH,

35

in which R denotes an alkyl, alkenyl or aralky radical and the resie optionally contain one or more other substituents, in an inert one Diluent under essentially anhydrous conditions in the presence of a catalyst.

The inventive method is characterized in that the reaction takes place at a temperature between 120 and 200 ° C in the presence of 0.1 to 20 mol percent, based on the cyclic ketone, Metaboric acid, its anhydride or one of its esters of the general formula

differs from the present process in that a completely different catalyst, najnhch a Friedel-Crafts catalyst, is used and If the reaction was carried out in the temperature range from 0 to 50%, while .m, present Case the reaction temperature between 120 and

"The present method has the advantage over the above-mentioned method that the use catalyst much easier to handle (in the known process, aluminum trichloride and sulfuric acid in particular are used as Fnedel-Caüs catalyst used, its handling due to the use of concentrated Sulfuric acid is more difficult to a certain extent, since extremely careful handling of the sulfuric acid must become).

Another advantage of the present process is the extraordinarily high selectivity which is achieved with the present method.

It is surprising that the implementation with such a high selectivity with the relatively high Temperatures can be carried out; because one had to expect that at these temperatures the Side reactions were increasing, which is compulsory lead to heavily contaminated products.

It could not be ruled out that with higher Temperatures cause extensive decomposition of the reactants would take place and that the yield of the desired product was correspondingly low would fail.

The cyclic ketones used in the process of the present invention are, for example Cyclopentanone, cyclohexanone

D> s used in the method according to the invention Hydroperoxide has the general formula

(R ₁ -OB = O) ,,,

in which R 1 denotes an alkyl, aryl, alkaryl or aralkyl radical and each of the radicals optionally contain one or more other substituents and η denotes an integer 1 or 3

Cyclic esters (lactones) are valuable intermediates, from which the corresponding lakuime can be produced, which in turn can be used to make nylon. The cyclic esters have so far been made by Oxidation of ketones produced. However, this production is associated with various disadvantages.

The German Offenlegungsschrift 940 409 also contained a process for the production of lactones from a cyclic ketone and a hydroperoxide in the presence of a catalyst in an organic Known solvents.

This process does not involve the usual parts of similar processes; it under-ROOH,

in which R denotes an alkyl, alkenyl or aralkyl radical and the radicals optionally contain one or more substituents.

R is preferably an alkyl or alkaryl radical. Suitable hydrogen peroxides are cumene hydroperoxide, cyclohexyl hydroperoxide, ethylbenzene hydroperoxide and tertiary butyl hydroperoxide. The latter two hydroperoxides are particularly preferred. The catalysts used in the process according to the invention are metaboric acid or its anhydride (B ₂ O ₁ ) - metaboric acid can be prepared by azeotropic distillation of orthoboric acid. According to a preferred embodiment of the present invention the catalyst is metaboric acid which is formed in situ. It is also possible to use a metaborate ester of the general formula (R —O — BO) _n , in which R ^{1 is} an alkyl, alkaryl or aralkyl radical, for example an alkyl radical having 1 to 12 carbon atoms, each of the radicals optionally being substituted and η is an entire number of 1 or 3, depending on the alkyl, aryl, alkaryl or aralkyl radical present. According to the invention, the metaboric acid or the anhydride or an ester thereof is used in a catalytic amount, and this can make up, for example, 0.1 to 20 mol percent, preferably about 10 mol percent, based on the amount of ketone.

The diluent used according to the invention is inert, i.e. it does not impair the reactants under the reaction conditions.

essential and it can for example be cyclohexane, 8.0 g of cyclohexane diluted and ge-ethylbenzene or toluene in a pressure vessel. Give this dilution. The reaction was carried out for 3 hours. The hydroperoxide reaction was carried out easily with a stirrer. The result was: 50% of the reaction partner was attacked, but not in such a way that this conversion of the ketone De. a selectivity of grip is detrimental to the process. But it becomes ₅ 90% Λ-valerolactone. it is preferred that the diluent be a hydrocarbon such as benzene. Example 6

The reaction is carried out at a temperature between ethylbenzene hydroperoxide (4.6 g). Cyclohexanone

see 120 and 200 ° C, depending on the re- _{y used} . ' _BenZ Q | ( ₂ 6 g) and boric anhydride

action partners carried out. The optimal tempe- _l0 ^ "'. R ^' _wurc i _en i _ne in glass reaction vessel with a

The temperature for the production of the esters is generally a minimum of 120 ml.

between 165 and 175 ° C. Temperatures between ' _b * _covered | _n stirrer was provided. The

However, 120 and 140 ° C are sometimes more favorable. The _reaction vessel was through a ring coupling with a

is preferred, the reactants and the encryption _pressure _ g _{e {a} ß _V on 15 kg / ^cm: and a security

diluent under sufficient pressure to keep 15 _{unit valve} connected.

keep all in the liquid phase u, and it will Reaktionsgetäß was out wide-preferably by immersion in a when one higher than at- _{ö |?} j _{bad on ng a} stirrer hotplate 2 hours mosphärischen press operates at a low _{o Q heated} during the reaction, the hydroperoxide concentration rose. for example about 10 _{pressure in the} system to 6.6 kg / cm ² . Weight percent. *> _{Manerhie t} i in this manner in order Encrypt-side reactions to decrease a 32%, ^ should _{by Cyc [o} h _e xanon in ε-caprolactone, wherein a compounds and metals, the Hydroperoxidzer- ₁₀ o% _lg e selectivity advertising initiate with respect to the consumed translation, kept to a minimum _K was achieved etonmenge, the. If a solid catalyst is used, insufficient stirring can also result in the formation of undesirable by-products at the expense of the chemical oxide (46 g). Cyclohexanone wished to favor esters. , Vi? ^ Äf% g) and boric anhydride The following examples illustrate the invention. 2.95 β). Benzene ^ (ZOg) J ^ ^ _{pressure vessel}

Example 1 ₃₀ analogous to Example 6 at 120 ° C. for 6 hours.

0.2 g boric anhydride, 2.0 g tertiary butylhy- The pressure in the Sys «™ ^ ™ ^ conversion droperox.d and 2.0 g cyclohexanone with 2.8 ^^^ S ^^^ * Ki the Selek-18.0 g of cyclohexane diluted and in a pressure of Cyclohexanonη ε-u> p _needed Ke-

given container. The reaction is carried out by heating tivitat, based on the amount of ver at 170 ° C for 4.5 hours with stirring. _J5 tons, 90%. A 70% conversion of the ketone is obtained in ReisDiel 8

90% of the selectivity of ε-caprolactone. ^v ■ ■, *. _A ^ ",.

⁸ "The implementation was carried out as in Example 6

Example 2 _{with the exception} that the benzene by 25 g

0 08 g boric anhydride, 1.0 g tertiary butylhy- ^ _{0 A} thy5benzene was replaced. The conversion of Cydroperoxid and 1.0 g of cyclohexanone were mixed with 9.0 g _c i _one xanon in ε-caprolactone was 6 A diluted wobei_ uie benzene and placed in a pressure vessel. The selectivity, based on the amount of reaction consumed, is carried out by heating to 170 ° C. for 4.5 hours of ketone, 93%, while stirring. You get one

65% conversion of the ketone with 95% Selek ₄₅ Example 9

activity on ε-caprolactone. _t . _B utylhydroperoxid (3 ^, cyclohexanone (3 g) and

Example 3 Metaboric acid (0.012 g) were mixed with BenzolI (24 g)

08 g of boric anhydride, 1.0 g of tertiary butylhydric acid and diluted droperoxide and 1.0 g of cyclohexanone with _{50 6 are} introduced into a pressure vessel analogously to the example. The reaction is carried out by heating benzene and placing the mixture in a pressure vessel. _au f etaer stirrer-hot plate at 145 C 2 hours, the reaction results in 4.5 hours at 140 ° C un- performed. One obtained a ² ™ * ξ ™ Nahrungsmittel * r * ^ r stirring. A 40% conversion _of cyclohexanone into ketone is obtained with a selectivity of 87% of the amount of ketone used, the Selewivi caprolactone being 92%.

Example 4

5.0 g tricyclohexyloxyboroxine, 1.2 g tertiary Bu - Example 10

tyl hydroperoxide and 1.0 g of cyclopentanone diluted.

one with 9.0 g tertiary butyl alcohol and gives the geo 'ysators to show, an experiment without metabormix became in a pressure vessel. The reaction is carried out acid, its anhydride or its ester, for! 7 hours at 120 ° C with stirring. 2.0 g tertiary butyl hydroperoxide and 2.0 g cyclo-

A 55% conversion of ketone with hexanone was obtained and diluted with 18.0 g of benzene and dissolved in 81% selectivity of ö ^ valerolactone. given a pressure vessel. The implementation was

6 ₅ by heating at 170 ° C for 4.5 hours with stirring

Example 5 carried out. There was no F-Ca-

1.6 g tricyclohexylboroxine. 0.5 g tertiary butyl prolactone using gas chromatography or hydroperoxide and 0.5 g of cyclopentanone were determined by nuclear magnetic resonance analysis.

Claims (1)

Claim: Expired to make lactones by reacting a cyclic ketone with 5 or 6 5 Carbon atoms with a hydroperoxide of the general formula ROOH,