JPS5936972B2 - Selective production method of phenylene diacetate - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing phenylene diacetate.

More specifically, the present invention provides oxygen,
It relates to the conversion of phenylacetate to phenylene diacetate at high temperature and pressure in the presence of acetic anhydride and acetic acid. More particularly, the present invention relates to a process for the preparation of paraphenylene diacetate as the main product. [The present invention is based on Japanese Patent Application No. 50671 of 1982 (Japanese Patent Application Laid-open No. 50671/1983) entitled "Oxy-acetylation of phenylacetate to metaacetoxyacetophenone using a palladium catalyst."
Publication No. 56233) C! f, National Application No. 137708)
It is related to. ]Phenylene diacetate may have utility as a solvent. The production of phenyl acetate is disclosed in US Pat. No. 4,156,783. Pd(0Ac)2 in acetic acid under oxygen atmosphere and N
The acetoxylation of chlorobenzene in the presence or absence of O2 and with metaselectivity has been proposed by Acta Chemica Scandinavia.
ndinavia) B28 (1974) 771-J Mo V6
, reported in El Everson et al.

In this specification, "Ac" refers to an acetyl group, that is, one CH3-q group, and "0Ac" refers to an acetoxy group, that is, one CH3-q group. ．． -C
It means -0-. The latter is 2,2'-Bipy in acetic acid.
The stoichiometric acetoxylation of phenyl acetate by Pd(0Ac)(NO3) at 115 °C under oxygen atmosphere is also disclosed, and after 2 h reaction time metadiacetoxybenzene (metaphenyl diacetate) acetate) is the main product (60%). The above reference is 597-60
On page 2, heterogeneous gas-phase acetoxylation of monofunctional benzene derivatives that occurs in acetic acid in the presence of oxygen reverses the normal substitution effect, i.e. substituents in the ortho, para direction are predominantly metaacetoxylated. , and those in the meta direction give ortho and para acetoxylation. The formation of methylbenzyl acetate via a homogeneous reaction between palladium l) acetate and paraxylene in the presence of oxygen in acetic acid was studied at Acta Chemica Scandinavia.
27, 1973, L. Everson et al. 1162-117
Reported in articles on pages 4, 1249-1254, and 1255-1267.

Acetoxylation of phenyl acetate with potassium peroxydisulfate in the presence of acetic acid to form 25% ortho, 42% meta and 33% para isomeric phenylene diacetate using Pd(2) as catalyst has been reported in Acta Chemica Scandinavia B3O. (1976) pp. 361-364, Everson et al. Palladium (n) (
(along with other components such as oxidants and co-oxidants)
Use to catalyze aromatic acetoxylation is described in U.S. Pat. Org. Chem, Volume 36, No. 1
No. 4, 1971, P. M. Henry, and J. S. C.C.
hem. COmm. Reported in the literature as exemplified by L. Everson et al., pages 1974885-886.

The acetoxylation of benzene to phenyl acetate using oxygen, palladium on silica or alumina in the presence of acetic acid is described in ErdOlUndKOhle, 2379,
Reported in 197O.

According to Journal of Organic Chemistry, Vol. 33, November 1968, by R. Bryant et al., acetoxylation of toluene at high temperatures in the presence of oxygen, palladium acetate and alkali metal carboxylates yields benzyl acetate and higher conversions. This produces benzylidene diacetate.

However, none of the references cited so far disclose or suggest converting phenyl acetate to phenylenedia, acetate via the process of the present application.

Furthermore, in contrast to the previously mentioned references (Acta Chemika Scandinavia B-28, pages 597-602 and 771-J Mo V6), the process of the present invention produces primarily paraphenylene diacetate isomers. The process of the invention consists of reacting phenyl acetate, acetic anhydride and acetic acid in the presence of a palladium catalyst and an inert gas under high temperature and pressure, and a gas mixture containing not more than 13% by volume of oxygen, and includes the following reaction: Thus, phenylene diacetate is produced. Since either acetic acid or acetic anhydride or both can be the source of the second acetoxy group attached to phenyl acetate, the above reaction equation is only representative of the possible reactions that may occur. . Paraphenylene diacetate is the major product followed by the ortho and meta isomers.

As used herein, the term "acetoxylation" refers to the addition of an acetoxy group CH3-9-0- to the organic compound being treated.

The process of the invention is conveniently carried out in the liquid phase under acetoxylation conditions, ie, temperature, pressure and oxygen levels that favor the formation of phenylene diacetate.

High temperatures of about 100°C to about 300°C are preferred, and about 150°C.
C. to 250.degree. C. is more preferred. Approximately 7.03 to 10.
5.5kg/~ (gauge) (approximately 100 psig to approximately 1
Reaction pressures of up to 500 psig are preferred. Reaction times vary considerably depending, in part, on operating conditions, including, for example, catalyst, relative concentrations of raw materials, temperature, and pressure used. The process can also be carried out in batch, continuous or semi-continuous mode. The amount of acetic acid is not critical.

A preferred range is about 0.2 to about 5.0 moles per mole of phenyl acetate. Acetic anhydride should desirably be present in an amount from about 0.1 to about 3 times by weight the amount of phenyl acetate used, with 0.3 to 1.5 times being preferred. The molar ratio of palladium catalyst to phenyl acetate used should be from about 0.0001 to about 1, preferably from 0.001 to 0.5. The amount of oxygen is the amount of acetoxylation.

That is, the amount of phenylene diacetate, preferably the para isomer, rather than the acetoxyacetophenone of the previously referenced pending application is enhanced. Oxygen is generally used in combination with an inert gas such as nitrogen. The oxygen content of the gas mixture should be kept low, e.g. no more than 13% by volume, preferably about 1-8% by volume,
Most preferably about 3-5% by volume. Above 13% by volume, the oxy-acetylation reaction of the pending application will predominate.

The palladium catalyst is preferably palladium on alumina.

Other palladium catalysts that would yield effective reaction mixtures may also be used, such as palladium acetate and other supports such as carbon and silica.

Generally, the present process results in substantial conversion of phenyl acetate to phenylene diacetate, with the para isomer being the predominant isomer.

Products other than phenylene diacetate may be produced, but in small, if not merely trace amounts. The selectivity with respect to paraphenylene diacetate is also quite high, for example in the example experiments the selectivity was 82%. The following examples are given to illustrate the invention described herein. EXAMPLE The following reaction was carried out in a stirred stainless steel autotale using 5% palladium on alumina (2.35 mmol), acetic anhydride (510 mmol), phenyl acetate (950 mmol) and acetic acid (4200 mmol) as catalysts. The reaction was carried out.

Autoclave under nitrogen (800 psig = 56.24
kg/ml) and heated to 200°C. Then 4% 02 and 960 of acetoxylated gas! ) N2 was passed through the heated mixture at a rate of 21 (80
0psig-56.24kg/Cd).

At the end of the experiment, the autoclave was cooled to room temperature and the products were analyzed by gas chromatography. The total product yield based on Pd was 80,001). Three products were detected by gas chromatography. Selectivity of orthophenylene diacetate, 14 (F6: selectivity of metaphenylene diacetate, 4%; and selectivity of paraphenylene diacetate, 82(f).

Only trace amounts of acetylated product were found.

Phenyl diacetate can be recovered and separated by known methods such as distillation and/or crystallization. Selectivity, as used herein, is defined as the mole percent of one isomer over all products. The above yields indicate that the para isomer is the major diacetate product and the ortho isomer is the minor diacetate product.

The meta isomer is present in only small amounts. These amounts can be varied by changing operating conditions, however, outside of the conditions of the present invention, they generally favor the formation of the para isomer as the predominant isomer. The use of D palladium catalysts, such as palladium acetate O, and other operating conditions were similar.

Claims (1)

[Scope of Claims] 1. It consists of reacting a reaction mixture consisting of phenyl acetate, acetic acid and acetic anhydride in the presence of a palladium catalyst and a gas mixture consisting of an inert gas and oxygen at high temperature and high pressure, A process for the acetoxylation of phenyl acetate in which the amount of oxygen in the mixture does not exceed 13% by volume, so that paraphenylene diacetate is produced as the main product. 2 Pressure range is approximately 105.5kg/cm^2 in gauge pressure
(1500 psig).
Method by term. 3. A method according to claim 1, wherein the temperature is from about 100°C to about 300°C. 4. A process according to claim 1, wherein the catalyst:phenyl acetate molar ratio is from about 0.0001 to about 1. 5 The amount of acetic anhydride is approximately 0.1 by weight relative to phenyl acetate.
A method according to claim 1, in which the amount is from about 3 times to about 3 times. 6. A method according to claim 1, wherein the amount of oxygen in the gas mixture is from about 1 to about 8% by volume. 7. A process according to claim 1, wherein the amount of oxygen in the gas mixture is approximately 4% by volume. 8. A process according to claim 1, wherein the palladium catalyst is selected from the group consisting of palladium on alumina, palladium acetate, palladium on silica, palladium acetate on silica and palladium on carbon. 9 The temperature is about 100° C. to about 300° C., the amount of acetic anhydride is about 0.1 to about 3 times the weight of phenyl acetate, and the molar ratio of catalyst to phenyl acetate is about 0.00.
01 to about 1 and the amount of oxygen in the gas mixture is about 1 to 8% by volume. 10. Process according to claim 9, wherein the catalyst is palladium in a support.