JP2757403B2 - Process for producing 2,3-dimethylbutenes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The present invention relates to a method for producing 2,3-dimethylbutenes by dehydrochlorinating 1-chloro-3,3-dimethylbutane.

<Prior art> 2,3-dimethylbutenes, that is, 2,3-dimethyl-1
-Butene, 2,3-dimethyl-2-butene is known as a raw material for medicines, pesticides, fragrances and the like, and 1-chloro-3,3
It is also known to produce dimethylbutane by dehydrochlorination in the presence of a catalyst.

For example, a method in which the reaction is carried out in the gas phase using silica, alumina, or the like as a catalyst (US Pat. No. 2,404,927), or a method in which the reaction is carried out by a so-called reactive distillation method using an alumina catalyst in the liquid phase (US Pat. No. 3,445,538) And so on.

<Problems to be Solved by the Invention> However, in the known methods, the activity of the catalyst is not sufficient, and the conversion and the yield of the target product are low. In addition, a large amount of by-products such as methylpentene is formed, and There were various problems, such as not being sufficient.

<Means for Solving the Problems> In view of the present situation, the present inventors have considered that 1-chloro-3,3-
As a result of intensive studies on the catalyst for dehydrochlorination of dimethylbutane, it was found that the above-mentioned problems could be solved at once by using a specific catalyst, and the present invention was completed by further various studies.

That is, according to the present invention, when 1-chloro-3,3-dimethylbutane is dehydrochlorinated to produce 2,3-dimethylbutenes, at least one catalyst selected from a magnesium compound, a calcium compound and a lanthanum compound is used as a catalyst.
Industrially superior 2, characterized by the use of compounds of 2,
The present invention provides a process for producing 3-dimethylbutenes.

 Next, the present invention will be described in detail.

1-chloro-3,3-dimethylbutane, which is a raw material of the present invention, can be industrially easily produced, for example, by reacting tert-butyl chloride with ethylene in the presence of a catalyst such as aluminum chloride. Yes, as long as they do not hinder the reaction of hydrocarbons, halogenated hydrocarbons, etc., they can be used even if they contain impurities.

The catalyst used in the present invention is a magnesium compound,
Selected from calcium compounds and lanthanum compounds, specifically, magnesium, calcium, lanthanum oxides, halides, hydroxides, sulfates, nitrates, phosphates, carbonates, silicates, borates And the like. More specifically, for example _{MgO, CaO, La 2 O 3} , MgCl 2, CaCl 2, LaCl 3, Mg
_{(OH) 2, Ca (OH} ) 2, La (OH) 3, MgSO 4, CaSO 4, La 2 (SO 4)
₃ , Mg (NO ₃ ) ₂ , Ca (NO ₃ ) ₂ , La (NO ₃ ) ₃ , Mg ₃ (PO ₄ ) ₂ , Ca ₃
(PO ₄ ) ₂ , LaPO ₄ , MgCO ₃ , CaCO ₃ , La ₂ (CO ₃ ) ₃ , Mg ₂ SiO ₄ , Ca ₂
SiO ₄ , La ₂ (SiO ₄ ) ₃ , MgBO ₃ , CaBO ₃ , La ₂ (BO ₃ ) _{3 and the} like can be exemplified.

An oxide is preferable for a magnesium compound and a calcium compound, and an oxide is preferable for a chloride and a lanthanum compound.

Among the magnesium compounds, calcium compounds and lanthanum compounds, calcium compounds are preferably used.

When the present invention is carried out in a gas phase, CaO or CaCl ₂ is particularly preferred, and when carried out in a liquid phase, CaCl ₂ is particularly preferred.

The catalyst used in the present invention is preferable because it has sufficient activity even when the above-mentioned compound is used alone, and may be used by supporting it on a carrier inert to the reaction such as activated carbon if necessary.

Usually, the catalyst is used after calcining at 200 to 600 ° C. under normal pressure in air or an inert gas such as nitrogen before the reaction.

Further, the catalyst may be calcined at 20 to 600 ° C. under reduced pressure for use. When the compound to be used as a catalyst is a hydrate or a hydrate, it is particularly preferable to carry out the dehydration treatment of the catalyst by calcination as described above. However, if a dehydrated product is used as the catalyst, the above dehydration treatment can be omitted.

The method of the present invention can be carried out by a gas phase method or a liquid phase method. When carried out by a gas phase method, for example, a magnesium compound,
A method in which a calcium compound or a lanthanum compound is formed into an appropriate particle size alone or in the form of a mixture containing a suitable binder or a binder, held in a reaction tube, and brought into contact with the vaporized raw material, that is, a so-called gas phase flow in a fixed bed. The reaction can be performed by a reaction method.

When the present invention is carried out by a gas phase method, the reaction is usually 180
It is carried out at a temperature of 400400 ° C., preferably 180-350 ° C.

The present invention can be preferably implemented also in a liquid phase method. In this case, the catalyst can be used by dispersing it in a raw material, or in some cases, in a liquid phase containing a suitable solvent. The liquid phase of the present invention can be carried out without a solvent, but an appropriate solvent may be used. The solvent may be any solvent that does not hinder the reaction, and examples thereof include hydrocarbons and halogenated hydrocarbons. As described below, as a method of implementing the present invention, 2,
When a so-called reactive distillation method is used, in which a reaction product of 3-dimethylbutene is distilled out of the liquid phase as a gaseous substance and separated, a solvent used for the liquid phase is compared with the raw material and the reaction product. Those having a high boiling point can be suitably used. As such a high boiling point solvent, various ones can be employed. For example, mineral oil, liquid paraffin, n-decane, n-tetradecane, n-tridecane, decalin,
Examples thereof include 1,2,2-tetrachloroethane, 1,2,4-trichlorobenzene, 1,2-dichlorobenzene, chlorobenzene, and the like, and a mixture thereof.

The liquid phase method of the present invention can be carried out by a batch system or a continuous flow system, and the industrial system is preferably a continuous flow system. In this continuous flow type reaction, the reaction product may be taken out of the reaction vessel as a liquid as it is, or may be separated and obtained by distilling it out of the liquid phase as a gaseous substance together with the generated hydrogen chloride gas. At this time, an appropriate distillation column is installed in the distilling part of the gaseous matter, and an operation (so-called reactive distillation method) of distilling out 2,3-dimethylbutenes having a lower boiling point than the raw material preferentially out of the system is performed. By doing
It is also possible to obtain the desired product at a higher conversion. Further, the rectification of the distillation column allows the target products 2,3-dimethyl-1-butene and 2,3-dimethyl-2-butene.
The butene production rate can also be varied.

When the present invention is carried out by a liquid phase method, the reaction temperature is usually
70-300 ° C, preferably 100-250 ° C. The liquid phase method is a more preferred embodiment in that a relatively lower reaction temperature can be employed as compared with the gas phase method.

In the method of the present invention, the reaction pressure is not particularly limited, but is usually 0.1 to 10 atm. The feed rate of the raw material depends on the reaction system, the reaction temperature, the reaction pressure and the like, but it is usually 0.01 to 10 kg per hour as indicated by the feed rate of 1-chloro-3,3-dimethylbutane per 1 kg of the catalyst.

In this reaction, a small amount of 2-chloro-2,3-dimethylbutane (CDB) is by-produced by re-reaction between the product, 2,3-dimethylbutenes and the eliminated hydrogen chloride. Can be recovered by distillation or the like after the reaction, mixed with the raw materials for the present reaction, and recycled. In addition, in order to reduce the production of CDB, the raw materials must be diluted with a suitable diluent, for example, nitrogen, noble gas, methane, ethane, propane, ethylene, propylene, butene, etc., pentane, hexane, octane, benzene, toluene, xylene, etc. And a diluent such as an aliphatic or aromatic hydrocarbon. In this case, even when an aromatic hydrocarbon is used as the diluent, the catalyst is characterized in that it hardly reacts with the raw material chloride or the produced olefin and the like, and substantially does not produce an alkylated high-boiling substance. .

Hydrogen chloride gas by-produced in this reaction can be absorbed in water, for example, and separated as aqueous hydrochloric acid, or can be easily separated as a residual gas component obtained by liquefying 2,3-dimethylbutenes. 1-chloro-3,3 which is a raw material of the invention
-Can be reused in the synthesis of tert-butyl chloride, which can be one raw material when synthesizing dimethylbutane.

The 2,3-dimethylbutenes formed are usually separated by distillation. 2,3-Dimethyl-1-butene and 2,3-dimethyl-2-butene can be isolated respectively.

In addition, 3,3-dimethyl-1-butene by-produced in a small amount in this reaction is also separated by distillation and mixed with the raw material of this reaction to form a mixture.
It can also be converted to 2,3-dimethylbutenes.

<Effects of the Invention> Thus, the desired 2,3-dimethylbutene can be obtained. However, according to the present invention, the activity of the catalyst is higher than that of the known method, the target product is obtained in high yield, and the selectivity is high. can get.

<Examples> Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to Examples.

Examples 1 to 5 and Comparative Examples 1 to 3 2 cc of the catalyst of Table 1 formed into 24-48 mesh was filled in a quartz gas-phase flow reaction tube having an inner diameter of 10 mm. The catalyst was calcined in air at 250 ° C. for 1 hour before use.

While the N ₂ gas flow 100 cc / min as a carrier gas, 1-chloro-3,3-dimethylbutane (hereinafter at 230 ° C.
NHC) was fed at a rate of 2.5 g / hr to carry out the reaction. The reaction gas was introduced into water, separated into an organic layer and an aqueous layer, and the organic layer was quantitatively analyzed by gas chromatography. Table 1 shows the results.

Example 6 Using 2 cc of a CaO catalyst (calcined in air at 400 ° C. for 1 hour)
The same experiment as in Example 1 was performed, except that a raw material liquid of NHC / n-pentane = 50/50 (wt / wt) was fed at 5 g / hr without flowing N ₂ gas.

As a result of analyzing the reaction solution, the conversion of NHC was 99.0%,
Selectivity is NHE 2.1%, DMB-1 24.2%, DMB-2 64.5%, CD
B3.0% and other 6.1%.

Example 7 Using 4 cc of a CaCl ₂ catalyst (calcined in air at 250 ° C. for 1 hour) and flowing N ₂ gas at 5 cc / min, NHC / toluene = 50/50 (wt / wt)
Was fed at 10 g / hr. Table 2 shows the results when the reaction temperature was changed from 180 ° C to 300 ° C.

The production of a high-boiling compound in which toluene was alkylated was not observed.

Example 8 Using 4 cc of CaCl ₂ catalyst, 6.1 g / hr of NHC without flowing N ₂ gas
The same experiment as in Example 1 was performed except that the reaction was carried out at a reaction temperature of 240 ° C.

As a result of analyzing the reaction solution, the conversion of NHC was 99.2%,
Selectivity is NHE 2.5%, DMB-1 26.0%, DMB-2 64.1%, CD
B2.7% and others 4.7%.

Example 9 A reaction tube made of quartz having an inner diameter of 18 mm was fired in air at 400 ° C. for 1 hour.
Filling the CaO catalyst 10 cc (24-48 mesh), 400 N ₂ gas
While flowing at cc / min, NHC was fed at a reaction temperature of 220 ° C. at a rate of 12.0 g / hr to cause a reaction. Table 3 shows the analysis results of the reaction over time.

Example 10 and Comparative Example 4 12 g of the catalyst powder and 30 g of liquid paraffin were charged into a simple distillation apparatus of a 100 cc four-neck glass flask equipped with a magnetic stirrer, a thermometer, a raw material supply port and a product gas outlet. The catalyst was dispersed by stirring, the reaction solution was heated to a predetermined reaction temperature, and the raw material NHC was continuously fed into the flask at a rate of 2.5 g / hr to carry out the reaction.

The reaction product containing HCl gas was distilled out of the system in a gaseous state, then led into water, separated into an aqueous layer and an oil layer, and the oil layer was analyzed by gas chromatography. Table 4 shows the results of the analysis of the reactions at various reaction temperatures in a steady state (where the amount of distilling off the product including HCl is almost equal to the amount of NHC fed).

Example 11 A long-time operation was performed in the same manner as in Example 10, except that the reaction temperature was fixed at 170 ° C.

After the start of the reaction, the distillate was appropriately sampled to analyze the reaction product, and the results are shown in Table 5.

Example 12 A 50 cc four-neck glass flask equipped with the same accessories as in Example 10 was charged with 5 g of CaCl ₂ dehydrated at 200 ° C. under nitrogen and 20 g of liquid paraffin.

A simple rectification column (inner diameter 10 mm, flow 150 mm) filled with a helipack was attached to the reaction gas distilling part, and the distilling temperature was controlled by external heating. NHC feed rate 2.5g /
Table 6 shows the analysis results of the distillate in the steady state when the distilling temperature was changed at a reaction temperature of 180 ° C. hr.

Examples 13 and 14 A 50 cc four-neck glass flask equipped with the same accessories as in Example 10 was charged with 5 g of dehydrated CaCl ₂ and 20 ml of decalin or o-dichlorobenzene as a solvent, and subjected to simple distillation.
The reaction was carried out at an NHC feed rate of 2.5 g / hr and a reaction temperature of 170 ° C. Table 7 shows the analysis results of the distillate in the steady state.

CaCl ₂ 10 g and NHC20m dehydrated in the same reactor as in Example 15 Example 13
l was filled. A condenser was provided on the distillation side of the flask, and the temperature was controlled so as to keep the distillation temperature at 40 to 50 ° C. The reaction flask was immersed in a 130 ° C. oil bath, and NHC was fed at a rate of 2.5 g / hr by a pump to perform a reaction. The analysis results of the distillate in the steady state (15 to 17 hours after the start of the reaction) were as follows. The reaction temperature (internal temperature) at this time is 113 to 1
15 ° C. The conversion of NHC is 99.9%, and the selectivity of each product is NHE 1.9%, DMB-1 34.6%, DMB-2 62.0%,
CDB was 0.9% and others were 0.6%.

Examples 16 and 17 and Comparative Example 5 The same apparatus as in Example 4 was charged with 4 g of the catalyst and 20 g of liquid paraffin.

The reaction was carried out by feeding NHC at 230 ° C. at a rate of 5.8 g / hr while flowing N ₂ gas at 120 cc / min as a carrier gas.

Table 8 shows the analysis results of the distillate 4 to 5 hours after the start of the reaction.

Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI C07C 1/30 C07C 1/30 // C07B 61/00 300 C07B 61/00 300 (56) Reference US Patent 2404927 (US, A) US Patent 3445538 (US, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C07C 11/107 C07C 1/30

Claims (2)

(57) [Claims] 1. A method for producing 2,3-dimethylbutenes by dehydrochlorinating 1-chloro-3,3-dimethylbutane, wherein at least one selected from a magnesium compound, a calcium compound and a lanthanum compound is used as a catalyst. A process for producing 2,3-dimethylbutenes, comprising using the compound of the formula (1). 2. The process according to claim 1, wherein the feed rate of 1-chloro-3,3-dimethylbutane per kg of catalyst is 0.01 to 10 kg per hour.