JPS58164531A - Preparation of alkanepolyol - Google Patents

Abstract

PURPOSE:To obtain an alkanepolyol, especially ethylene glycol at relatively low pressure, and to recover a rhodium compound in an active state, by reacting CO with H2 in the presence of a rhodium-based catalyst using an N-alkylurea as a solvent. CONSTITUTION:In preparing the titled substance by reacting CO with H2 in the presence of a rhodium-based catalyst, an N-alkylurea is used as a reaction solvent. A tetraalkylurea shown by the formulaI(R1-R4 are 1-6C aliphatic hydrocarbon) and an N-alkylalkyleneurea shown by the formula II (n is 2, 3 or 4) may be cited as the N-alkylurea. It is used in a mixed solvent with another solvent (e.g., tetraglyme) in its 5-100wt%. The reaction is preferably carried out at 30-1,000kg/cm<2> at 120-300 deg.C. EFFECT:A high formation speed and selectivity of especially ethylene glycol is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides the following methods: - Reacting carbon oxide and hydrogen in contact with each other,
This invention relates to a method for producing an alkane polyol.According to the present invention, it is possible to efficiently produce an alkane polyol under low pressure.

Conventionally, many methods have been proposed that use rhodium-based catalysts as a method for directly producing ethylene glycol from alkane polyols by reacting carbon oxide and hydrogen. - Regarding the production of ethylene glycol. Rhodium has superior catalytic activity compared to working metals, but since rhodium is an expensive metal, it is necessary to increase the rate of ethylene glycol production per unit rhodium atom, and to efficiently recover and recycle rhodium. Since this is an important issue in the practical application of this process, one of the important factors to solve the above-mentioned issues is considered to be the selection of the reaction solvent, and several methods have been proposed from this point of view. For example, in JP-A No. 1851-32IO7, r-buty-a9tatone and 1-pareloxtone solvents are used, and in JP-A-1851-aseoz, dimethylsulfone or tetramethylenesulnene solvent is used. -4
Bulletin No. 2808 proposes the use of a mixed solvent of tetraglyme and sulfolane, and Bulletin No. 411-1!4204 proposes the use of a crown ether solvent. However, only rhodium metal compounds and these solvents are suitable for O reaction systems. In this case, almost no production of ethylene glycol was observed at a reaction pressure of 1000 Kf/- or less, and N and N are usually used as a means to increase the amount of ethylene glycol in the reaction pressure range described above.

Methods have been proposed in which organic nitrogen ligands such as NzN'-tetramethylethylenediamine (e.g., JP-A-48-18509), alkali metal cations (e.g., JP-A-1@51-36403), etc. are used as promoters. ing. In addition, W. Kei m et al.
Catalysis, however, 359-16SC1980)
reported nine results using N-methylpyrrolidine solvent, but the results were carried out under harsh conditions with a reaction pressure of 2,000 bar.

In view of the importance of the reaction solvent in this reaction system, the present inventors conducted a wide range of solvent studies and used N-alkylureas as the reaction solvent even in systems where the above-mentioned cocatalyst is not present. Surprisingly, they discovered that it is possible to efficiently produce alkane polyols under relatively mild reaction pressure conditions, and have completed the present invention.

That is, the present invention provides a method for producing an alkane polyol by reacting carbon oxide and hydrogen in the presence of a rhodium-based catalyst, the method comprising using N-alkylureas as a reaction solvent. is to provide.

The N-alkylureas used in the present invention include tetraalkylureas represented by the following general formula (RIRI NCNR5Ra = (1), where R1, R
-, R4 are aliphatic hydrocarbons of C1 to -, respectively, and N-alkylalkylene ureas represented by formula 1, provided that R1, Rx Fi are aliphatic hydrocarbons of Ct-6, n There are integers from 2 to 4. More specifically, N, N, N'-tetramethyl rat, N, N, N';N'-tetranibruurea,
N, N, Ns dotetraglobilurea, N, N, N'
-tet'y(n-butyl)urea, N,N-dimethyl, N
',N'-diethylurea, N,N'-dimethylethyleneurea, N,N'-diethylethyleneurea L N,N'-diimpropylethyleneurea, N-methyl,N'-isopropylethyleneurea, N , N'-dimethylpropyleneurea, N,N'-dimethylethyleneurea, and the like. Among these, in particular, N is considered to be generally easily available industrially.

It can also be used as a mixed solvent system with ether 11'&. In this case, the number of ureas in the mixed solvent is 5 to 5.
It is used in an amount of 100% by weight, preferably in the range of 10 to 160% by weight.

The present invention is characterized in that it provides a high rate of production of alkane polyols, especially ethylene glycol, and high selectivity for ethylene glycol under relatively mild reaction conditions.

A further point to be noted is that after the nine-rhodium compound is supplied to the reaction system and the reaction is completed, it can be recovered as p-diium metal without being deposited inside the reactor and inactivated.

The rhodium-based catalyst used in the method of *fj is:
Anything that does not go beyond the spirit of the invention may be used. Furthermore, it is also possible to use rhodium carbonyl complexes having complex bonds with -carbon oxide or carbon monoxide and hydrogen. These p dicum carbonyl anchors include so-called rhodium carbonyl clusters, rhodium hydride carbonyl clusters, and the like. For example, dirhodium octacarbonyl, tetrarhodium dodecacarbonyl, hexfc1dium hexadecacarbonyl, -rhodium trisacetylacetonate, rhodicumcarbonyla heptylacetonate and (Rh(CO)n
)-, (likg(Co)z algae) 3-1 [rikg(CO)
14)'-1[Rhy(CO)ms)"-1(R111
s(CO)io)"-, CRks(CO)xiI)-1
Examples include salts with organic, t, or inorganic cations such as CRhs(CO)uC)''-.

t, preferably from 1 x 10''1 to I x 10-'
Durham atoms are used in the 7to range. In this case, the N-alkyl phenolic compound used in the method of the present invention, which is the reaction *m for solubilizing or suspending the dicum compound, may be used alone or in a limited amount that does not impair the effect of the solvent O. It can be used as a mixed solvent of II and O1.

In the method of the present invention, the reaction is carried out under heating and pressurizing conditions.6 The reaction pressure is usually 2.0 to 2.0 mm/-G1, preferably 3 to 1. According to the method of the present invention, the yield of alkane polyol is large even without using a cocatalyst under relatively low pressure, and the selectivity of alkane polyol is high.KI
There are signs of flI.

The molar ratio of sulfur monoxide and hydrogen gas to be supplied to the reaction system as raw material gases for producing the alkane polyol of the present invention is usually O,
OSm2O3 is preferably in the range of 0.1 to 1.0. Further, the reaction temperature is usually 50 to SSO°C, preferably 1 to 100 °C, and the reaction time is usually 0.1 to 20 hours, preferably 0.3 to 10 hours. - is used.

In the reaction product obtained in the Motoya W14o method,
In addition to alkane polyols such as ethylene glycol, propanediol, and glycerin, they include monoalcohols such as meta/-h, x-tanol, and esters of formic acid and acetic acid. As a method for separating the target alkane polyol from these reaction products, known techniques such as steaming and extraction can be used.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Example-1 Hastelloy C# with an internal volume of 100M1! The autoclave was filled with 20117 N, N, -tetramethyl wL atoms and 0.8 milligram atoms of tetrarhodium dodecacarbonyl. After this autoclave was installed in a heating furnace, carbon monoxide and hydrogen were introduced from the gas inlet pipe. The molar ratio of
The gas in the system was replaced by introducing and exhausting a 10% mixed gas several times until the O charging pressure was 2 It OKg/cd.
The temperature of the 0 reaction at which the heating gas was charged so as to be 20 (I
Set CE and conduct the reaction for 4 hours from the point in time when the temperature in the reaction system reaches 200°C.

・After the reaction is complete, cool the autoclave to temperature and:
↓The gas component was released and the liquid product was recovered.

This was quantified by Gask I Madogutfy, 441i, 91.72 nort, s.
s mmol is generated. Traces of ethanol, methyl formate, and 1,1-propanediol were detected in other line 6 components, and traces of methane and carbon dioxide were detected in the gas components. 9. When the rhodium in the liquid product was quantified, it was found that more than 8% of the charged rhodium O. was recovered.

Example-2~S Table 1 shows the nine-force reaction S* in Example-1ON.

From N,N'',N'-tetramethylurea to N,N'-dimethyl An experiment was carried out in the same manner as described in Example 1, and the results shown in Table IK were obtained.

(Leaving space below) Table-1 Example-6 Example-1 except that 0.1 (ligram atom □odium dicarbonylar tylacetonate was used as a catalyst)
A reaction similar to that of
Millimoles were being produced.

As shown in Table 2 for the reaction Minato Gen, tetraglyme, r
-Ptylorataton, Sulfolane, 18-Lorie, Higashi, In Examples 1 to 6, the reaction solution was all diluted as a homogeneous solution, but in Comparative Examples 1 to 2, it seems to be metal diu^. A black precipitate was formed, and the amount of rhodium present in the solvent was less than 1s% of the sodium carbonate charged.

(Margin below) Table-2

Claims (1)

[Claims] 1. A method for producing an alkane polyol by reacting carbon monoxide and hydrogen in the presence of a rhodium-based catalyst, the method comprising using an N-alkylurea as a reaction solvent.