JPS6094940A - Production of cinnamic acid ester - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing cinnamic acid esters. Specifically, the present invention relates to a method for producing citrate esters by oxidatively carbonylating styrenes in the presence of alcohol.

Cinnamic acid is cinnamaldehyde, cyclamenaldehyde, β-
It is a pesticide used as a fragrance raw material along with amyl cinnamaldehyde.

For a method for producing cinnamic acid ester by oxidative carbonylation reaction of styrene, see, for example, JP-A-Sho! J-4I
θri09, Tokukaisho, tA-/, tko4'J, 4? R.A.,
! i A-λko7da? , Tokukai Showa S Mi-Yukotro.

JP-A Showa 5t-tio3 de, JP-A Showa tough-knot 3g λ, JP-A show 37-ko 13 da J1 JP-A show! 70536, etc.

In JP-A-Sho & A-, 227 Da9, the reaction is carried out using palladium chloride, cupric chloride, and a tertiary amine as a catalyst under conditions where the partial pressure of carbon oxide is / II Kg/c4G or less. , ethyl cinnamate was obtained at a yield of 3%, 0% to 30.3%, based on the consumed styrene. In addition, in JP-A-5A-, 22-ri 5θ, JP-A-Sho Art-
: Using the same catalyst as palladium chloride, cupric chloride, and tertiary amine as in 12ri'19, the partial pressure of carbon monoxide in the reaction system was maintained at or above / g Kr /ctl G, and the reaction was continued. The ratio of carbon monoxide partial pressure to oxygen partial pressure in the system (Pco/Pot) was maintained below k'I, and the yield of ethyl cinnamate was 4.3% to 3.9% (relative to consumed styrene). It has gained. Furthermore, JP-A-10-/aAA
In O&, when producing esters of carboxylic acids having one or more carbon atoms than the olefin from olefins, alcohols, oxidized oxygen, and oxygen, Group S noble metals are used as catalysts, and the reaction system is It is preferable that the carbon monoxide partial pressure is pressurized, more preferably S atmosphere or higher, and in specific examples, the reaction is carried out at a carbon monoxide partial pressure of around 60 atmospheres. . However, in this reaction, the yield of saturated carboxylic acid is high, and nothing is described regarding cinnamic acid esters.

On the other hand, in JP-A-57-7θ Za 3A, (a) platinum metal or its salts, (b) copper or iron salts, and (c) alkali metal or alkaline earth metal Methyl cinnamate is obtained using a catalyst system consisting of seven or more compounds selected from hydroxides, carbonates, and acetates. In this, we will consider the partial pressures of two types of gases, carbon monoxide and oxygen, which are reaction substrates, and the oxygen partial pressure in the reaction system is not particularly limited. Carbon monoxide has a high partial pressure. Although the reaction rate is higher in this case, on the other hand, the amount of by-product of phenylsuccinic acid dialkyl ester increases, so the partial pressure of -carbon oxide is 30 Ky/cd or less, especially O1θ left ~ 2 k K4 /
It is stated that it is preferable to hold it at ctrt.

The inventors of the present invention have conducted intensive studies to industrially advantageously produce cinnamic acid esters using inexpensive raw materials, and have made a detailed study of the behavior of the amount of carbon dioxide by-product produced in the oxidative carbonylation reaction. discovered that cinnamic acid esters could be produced with extremely high selectivity by carrying out the reaction while maintaining the carbon monoxide partial pressure and oxygen partial pressure within the reaction system, and achieved the present invention. did.

Namely, the object of the present invention is to provide an industrially excellent method for producing cinnamic acid esters by oxidative carbonylation of styrenes, and the object is to provide (a) palladium metal in accordance with the present invention. or a compound thereof, (b) copper-
Alternatively, a cinnamic acid ester is produced by reacting styrene with an aliphatic alcohol having 1-d carbon atoms, carbon oxide, and oxygen in the presence of iron salts and (C) alkali metal or alkaline earth metal salts. At this time, the partial pressure of carbon monoxide in the reaction system was set to 0. /Kq/crAa or above, 7 guns have 9/a (l or above, lχ pressure has 11+1 and 1
, (2), can be easily achieved by carrying out the reaction while maintaining the ratio of carbon differentiation to carbon dioxide partial pressure between 1.0 and S.

The present invention will be explained in detail below.

The styrene used in the method of the present invention has the general formula (wherein R1 represents hydrogen, halogen, an alkyl group with a number of carbon atoms/~2 or an alkoxy group with a number of carbon atoms/~1, and R2 represents hydrogen or a carbon represents an alkyl group having an atom number of 1 to 2), specifically styrene,
Examples include β-methylstyrene, p-methylstyrene, p-methkinstyrene, p-chlorostyrene, β-methyl-p-isopropylstyrene, and β-amylstyrene.

Specific examples of aliphatic alcohols with a carbon atom number of ~g/~g include methanol, ethanol, inpropyl alcohol,
Examples include n-7' methyl alcohol, -butyl alcohol, etc., but acetals, ketals, carboxylic acid orthoesters, dialkoxychloroalkanes, orthoboric acid esters, etc. dissociate in the reaction system to release the above alcohols. Compounds obtained can also be used.

The above-mentioned styrenes are usually used in a molar ratio of θ0.8' to these aliphatic alcohols, preferably OJ to i,
used at a rate of o.

- Carbon oxide and oxygen can be used in a pure state, but they can also be used diluted with an inert gas such as nitrogen or argon.

In carrying out the method of the present invention, either a batch reaction method or a flow reaction method can be adopted, but in the present invention, the partial pressure of carbon monoxide in the reaction system is reduced to 0.0 at the start of the reaction and during the reaction. /Kg/a/ia to 7Kg/c4a1 preferably 0, /Kq/ctd from G! r Ky
/cr/I G , more preferably 0, 2-3
The ratio of the carbon monoxide partial pressure to the oxygen partial pressure in the reaction system must always be maintained between 3 and 3, preferably between 8 and λ and θ. be.

In the method of the present invention, it is thought that by maintaining the carbon monoxide partial pressure in the reaction system at 7~/cr/icj or less, the water produced by the reaction has a protective effect on its formation. This makes it possible to suppress the total amount of carbon dioxide by-product produced to a relatively small amount, and at the same time maintain the partial pressure of carbon monoxide relative to the partial pressure of oxygen (pco/po2) within the range from i, o to co, left. p1Pco/po, >;1. !
By avoiding the fact that under the conditions of i, phenylsuccinic acid dialkyl esters are produced as the main products, and on the other hand, under the conditions of Pco/po <80, the alkylallyl ketones are produced as the main products, and This makes it possible to produce all of the target cinnamic acid esters in very good yields. In order to maintain the -carbon oxide partial pressure and oxygen partial pressure within the above-mentioned ranges, it is preferable to use an inert gas so that the reaction system does not fall within the explosive range.

The reaction according to the method of the invention is carried out in the presence of (a) palladium metal or a compound thereof, (b) a salt of copper or iron, and (C) a salt of an alkali metal or alkaline earth metal.

Examples of palladium include metal palladium such as palladium with a carrier, zero-valent palladium complexes such as tetrakis(triphenylbosphine) palladium, inorganic salts of divalent palladium such as palladium chloride and palladium nitrate, and palladium acetate. , divalent palladium carboxylates such as palladium benzoate, and covalent palladium complexes such as bis(acetylacetonato)palladium and bis(triphenylphosphine)dichloropalladium.

When using these palladiums supported on a carrier,
Silica, alumina, silica alumina, magnesia, titania, diatomaceous earth, activated carbon, graphite, barium carbonate,
Calcium carbonate and the like are used as carriers.

Examples of salts of copper or iron include copper or iron hydrochlorides, nitrates, sulfates, phosphates, borates, etc. Salts of alkali metals or alkaline earth metals include inorganic salts such as hydrochlorides, acetates, etc. , propionate, butyrate, pivalate, stearate, and other organic acid salts.

The mixing ratio of these three components used as a catalyst is an atomic ratio of palladium metal or its compound to copper or iron salts: /:0. /~ri θO1, preferably l vs. 10 to 30
It is appropriate to use it so that it is in the range of 0.

The molar ratio of copper or iron salts to alkali metal or alkaline earth metal salts is /:0. / to ioo, preferably / to O1,8' to θ.

When carrying out this reaction, there is no problem even if no reaction solvent is used, but in some cases, an appropriate inert solvent may be used to facilitate the operation. Examples of inert solvents include ethers such as diethyl ether, diphenyl ether, dioxane, tetrahydrofuran, and ethylene glycol dimethyl ether, ketones such as acetone, methyl ethyl ketone, dibutyl ketone, and acetophenone, methyl acetate, ethyl acetate, ethyl propionate, and benzoic acid. Esters such as benzyl and dimethyl phenylsuccinate, aromatic hydrocarbons such as benzene, toluene, p-xylene, and ethylbenzene, aliphatic or alicyclic hydrocarbons such as n-hexane, n-octane, and cyclohexane. , carbonates such as ethylene carbonate and propylene carbonate, and amides such as acetamide and N-methylpyrrolidone.

In the method of the present invention, by increasing the reaction temperature,
Although the yield of cinnamic acid esters can be improved,
If the temperature is too high, side reactions such as carbon dioxide formation will occur, and the selectivity of cinnamic acid esters will decrease. be.

For the reaction product liquid obtained by carrying out the method of the present invention,
By employing conventional separation means such as distillation and extraction,
Cinnamate esters can be separated and obtained.

In the present invention, as described above, <0. / ＜Pco ＜ '
), θ and /, 0≦Pco/Po, ≦Co, j, cinnamic acid esters can be produced with high selectivity by carrying out the reaction under very limited specific conditions.

Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

Example / In a spinner agitation type Hastelloy C autoclave with an internal volume of 90 m1, styrene, methanol 3 vtt, zt
p→d/A, a, pa is 0.25 mmot (3% by weight of palladium supported on activated carbon), 0.25 mmot of cupric chloride. ! r mmot, barium acetate J, (7 mmot
was charged, and after sealing, 6.3 kg/di G of -carbon oxide was press-fitted. Next, l-% Ox/kJt (nitrogen containing 6 volumes of oxygen) was injected and the total pressure was reduced to s Kg/cdG.
And so. The autoclave was heated to ioθC and the reaction was carried out for 30 minutes. After the reaction was completed, the autoclave was cooled with water and depressurized, and the reaction gas composition and product liquid composition were analyzed by gas chromatography.

As a result, methyl cinnamate tr, g q mmo
t.

carbon dioxide/, 09 mmot, methyl cinnamate selectivity [
(Methyl cinnamate)/(methyl cinnamate + co- and methyl 3-propionate + acetophenone + dimethyl phenylpropionate) x lOθ]911, lArch.

What is the total pressure after the reaction is complete? A,! r Kf/ada had decreased. Also, the amount of carbon oxide absorbed is / da, 9 da B
mot, the amount of oxygen absorbed! In Example 1, - carbon oxide partial pressure and total pressure tube Table 1 below: r,'l/mmoA
All reactions were conducted under the same conditions except for the conditions shown in . The results are shown in Table 1.

Example 3 In Example 3, S%Pd/mu, 0. θ, kojmmo
t is palladium chloride (pdcts) 0-06 mmO
The reaction was carried out under the same conditions except that the conditions were changed to 2.

As a result, methyl cinnamate g, 0/mmol
, carbon dioxide θ, 9 K mmot, methyl cinnamate selectivity 90, and 3%.

Example 6 The reaction was carried out under the same conditions as in Example 1 except that cupric chloride θj mmot was changed to ferric chloride θ,A; mmot.

As a result, the produced methyl cinnamate, k 2 mmol
.

To carbon dioxide-/mmot, methyl cinnamate selectivity was 30%.

Example 7 Example/In! r% Pa/A, a, 00.2
! r mmol! %P(1/A, 0.0.Oj mm
ot, also barium acetate 3. The reaction was carried out under the same conditions except that Ommot was changed to lithium acetate/ommot.

As a result, methyl cinnamate AJ commoz was produced.

The selectivity of methyl cinnamate to carbon dioxide was 90.21%. The amount of carbon monoxide absorbed at this time is / 3. A g mmot, the amount of oxygen absorbed is da, /θm
It was moz.

Example g In Example/, 3% Pd/A, c, θ, cojmmO
1 to j% pd/A-0,0,0j mm0t, and barium acetate 3. Ommol to 80mmol of sodium acetate
The reaction was carried out under the same conditions except that t was changed.

As a result, methyl cinnamate AJ/mmot was formed.

Carbon dioxide, 9 mmot, methyl cinnamate selectivity is 9
k, g was 9%.

Example? In the example/! %Pd/A, O, θ, 2 km
mot to 5% Pd/a, o, θ, OA; mmol;
Also barium acetate 3. Ommot as magnesium acetate θ
,! The reaction was carried out under all the same conditions except for changing to r mmot.

As a result, methyl cinnamate t,! ; 3 mmo
t.

Carbon dioxide/,/Ommot, methyl cinnamate selectivity was Kuku, CoA%.

Example 1θ Hastelloy C11 with an internal volume of -〇〇ml equipped with a magnetic induction rotary stirrer, a reflux condenser, a gas introduction pipe, and a liquid extraction pipe.
Autoclave with 5% Pd/a,o.

QJ mmol as Pd, cupric chloride/0. O
mmot.

Filled with barium acetate 3θ, Ommot, styrene 30-1 and methanol 70d, nitrogen/oxygen/-carbon oxide mixed gas (Kof, Ada/Hedak/Heg?) was introduced.
While maintaining this pressure, the reaction temperature was gradually increased while flowing the mixed gas at the reactor outlet gas flow rate/gjJNt/hr.
It was set as oC. The reaction was carried out for 3 hours under these conditions while flowing the mixed gas and extracting a small amount of the reaction liquid every hour and analyzing it by gas chromatography.

Gas components were analyzed by taking out a portion of the gas phase at the exit from the reflux condenser and using gas chromatography.

The average amount of methyl cinnamate produced is /J,? rimmot/h
r, the average amount of carbon dioxide produced is 80? mmot/hr
Met. The selectivity of methyl cinnamate was 1%.

Comparative example/ In Example 1, -carbon oxide partial pressure was set to 15. .

The reaction was carried out under the same conditions except that Ky/ct/la was charged, followed by 6%-Os/n, and the total pressure was adjusted to /Ok, 0 to /cda. As a result, methyl cinnamate is /J,? 3. mmot, carbon dioxide, I
I II mmol was produced, and the selectivity of methyl cinnamate was 7.
q,i was 7%.

Comparative Example / Example / θ, nitrogen/oxygen/-carbon oxide mixed gas (8.λ, 2//, 01/!, □) t- is introduced and the pressure is increased to ? The reaction and analysis were carried out under the same conditions except that 4I,s Kf/cdla was used. The average amount of methyl cinnamate produced is tog? mmot/hr The average carbon dioxide production was /0.26 mmot/hr. Also, what is the selectivity of methyl cinnamate? ? ,? 7
%, the main product was dimethyl phenylsuccinate.

Comparative Example 3 Example IO except that a nitrogen/oxygen/-carbon oxide mixture gas (,yo,q/t,r//,J) was introduced and the pressure was set to 3j,j1'4/cdG. All reactions and analyzes were performed under the same conditions.

The average amount of methyl cinnamate produced is: i, g k mmo
The average amount of carbon dioxide produced in t/hr is 8! r9mm
It was oL/br. Also, the selectivity of methyl cinnamate is /'
The main product was acetophenone.

Sender: Mitsubishi Chemical Industries, Ltd. Representative patent attorney required - <n or 7 people)

Claims (2)

[Claims] (1) (a) Palladium metal or its compound, (b
) a salt of copper or iron; and (c) a salt of an alkali metal or alkaline earth metal. When producing the above, the partial pressure of carbon monoxide in the reaction system should be set to 0,/Kg/caG or more. b
/ ct/l G or less, and the reaction is carried out while maintaining the ratio of carbon monoxide partial pressure to acid system partial pressure between 7.0 and λ,3. manufacturing method (2) In the method for producing cinnamic acid esters according to claim 7, the styrene is represented by the following general formula (wherein R' is hydrogen, hydrogen, an alkyl group having 1 to 2 carbon atoms, or R2 represents hydrogen or an alkyl group having 1 to 6 carbon atoms.