KR100904298B1 - Method for producing tetralone by catalytic oxidation of tetralin over transition metal containing molecular sieves - Google Patents

Abstract

Synthesis methods of the present invention aluminophosphate molecular sieve (HMA), silica molecular sieve (MCM-41), and aluminophosphate molecular sieve (AlPO ₄ -5) made non-uniform by the molecular sieve containing the transition metal-containing catalyst, such as And, under the heterogeneous catalyst prepared by performing a specific washing process after firing it, liquid partial oxidation of tetralin under the optimum reaction conditions, thereby improving the conversion and selectivity of tetralin, especially The present invention relates to a method for preparing tetralon, in which the durability and activity of the catalyst are maintained even when the catalyst is reused by the washing process.

Aluminophosphate molecular sieves, silica molecular sieves and aluminophosphate molecular sieves, tetralin, tetraral, liquid phase partial oxidation

Description

Method for producing tetralone by catalytic oxidation of tetralin over transition metal containing molecular sieves

The present invention relates to a method for producing tetraral by liquid phase partial oxidation of tetralin under optimum reaction conditions with heterogeneous catalysts in which specific molecular sieves and transition metals are mixed in a certain component ratio.

In addition to sulfur compounds, transport oils are increasingly regulated by nitrogen oxides (NOx) and particulate matter (PM). In Europe, the PM has been tightened from 0.25 g / kWh in 1998 to 0.02 g / kwh in 2006. (Euro V), NOx also strengthened environmental regulations from 6 g / kWh in 2002 to 3 g / kWh in 2006 (Euro IV). In Korea, Euro III went into effect in 2002 and Euro IV went into effect in 2006.

As the regulation on PM of transport oil is strengthened, it is possible to drastically reduce its emission. By adding oxygenate to transport oil, it is possible to minimize PM by inducing complete combustion of transport oil in automobile engine. Is trying to solve.

Oxygenates synthesis technology refers to a technology that converts an aromatic ketone, an aromatic ether, etc. by selective oxidation using a large amount of mono-aromatic compounds in the crude oil fraction. For example, the synthesis of tetralin by selective oxidation of tetralin has the advantage that cetane number is enhanced and PM can be significantly reduced by inducing complete oxidation during combustion.

The results of tetralon production through the partial oxidation pathway of tetralin are very limited and are often mentioned as part of the normal liquid phase oxidation of hydrocarbons. Homogeneous catalyst systems are the majority of thesis, vanadium-based VO (acac) ₂ catalysts using oxygen as the oxidant [J. Mol. Catal. A: Chemical 179 (2002) 65] and manganese Mn (III) -porphyrine catalysts [Tetrahedron Letters 43 (2002) 1881, J. Mol. Catal. A: Chemical 113 (1996) 3], Manganese catalyst using hydrogen peroxide as oxidant [J. Mol. Catal. A: Chemical 232 (2005) 135], a phase transfer catalyst that studied the reaction of two organic / aqueous phases, using a copper catalyst and oxygen as an oxidant [Tetrahedron Letters 37 (1996) 2063], Using vanadium catalyst and oxygen [J. Mol. Catal. A: Chemical 164 (2000) 109], tetravalent ammonium salts and oxygen oxidizers [J. Mol. Catal. A: Chemical 120 (1997) 125], but most of the research has only been carried out to confirm the mechanism or catalytic ability of the reaction from a purely scientific point of view (chemistry).

US Pat. No. 4,283,352 (1981) to Yamaguchi et al. First oxidizes tetralin with oxygen and decomposes the resulting tetralin hydroperoxide by adding metal salts such as iron and copper to obtain tetraralone. A two step method was reported. Robert et al., US Pat. No. 4,960,944 (1990), performed oxidation at 7-14 atm using hydrogen peroxide as an oxidant and copper and iron oxide as catalysts. However, in the selective oxidation process using such a homogeneous catalyst, the separation and removal of the catalyst is a problem.

In addition, as a heterogeneous catalyst, the chromium-aluminophosphate (Cr-APO) molecular sieve catalyst was introduced as a tetralin partial oxidation reaction catalyst by the Sheldon group of the Netherlands, a global partial oxidation catalyst expert, but it was an intermediate of tetraron. It was reported that the selectivity for tetralin-hydroperoxide was high [J. Catal. 153 (1995) 1]. In addition to this, the British Thomas group reported that aluminophosphate (APO) catalysts, which are generally transition metal-substituted, showed superior performance in inactivating alkane with oxygen as an oxidant [Acc. Chem. Res. 34 (2001) 191. Coon at Union Cabide used a polymer catalyst exchanged with chromium ions, but reported low conversion and selectivity (US Pat. No. 4,473,711 (1984)).

As described above, the results of the tetralin production through the partial oxidation pathway of tetralin are extremely limited, and most of them are mentioned as part of the liquid phase oxidation of general hydrocarbons. In addition, the papers and patents related to the production of tetralon from conventional tetralin have been mainly made for homogeneous catalysts, and in the case of heterogeneous catalysts, tetralin is rarely used as a reaction precursor, and a few patents Reaction activity and selectivity are insufficient for commercialization.

A method for the conversion of petroleum to tetrachloric acid, which is an oxygen-containing fraction, can be obtained by the liquid partial oxidation reaction using tetralin. As a result, a heterogeneous catalyst containing a molecular sieve selected from hexagonal mesoporous aluminophosphate molecular sieves, hexagonal mesoporous silica molecular sieves and microporous aluminophosphate molecular sieves, and a transition metal at a constant ratio, When the liquid partial oxidation of tetralin was performed by optimizing the reaction temperature, the time and the concentration of the oxidizing agent in a specific range, it was confirmed that the conversion and selectivity of tetralin were excellent.

In particular, when the heterogeneous catalyst is used to remove the transition metal existing outside the lattice structure of the catalyst by using ammonium acetate after firing, it is confirmed that the deactivation of the catalyst by the elution of the transition metal as the active ingredient is minimized. Could.

The heterogeneous catalyst of the present invention uses tetralin, which is a representative component in the mono-aromatic fraction, as an oxidant, and has a high cetane number-promoting effect and causes complete oxidation during combustion, thereby reducing particulate emissions. It is economical because it has high selective partial oxidation reaction activity and high selectivity and stability to produce oxygen-containing oil such as tetralone with high effect.

The present invention is a method for producing tetraral by performing liquid partial oxidation of tetralin in the presence of a catalyst system and an oxidizing agent, wherein the catalyst system has a pore size of 2 to 20 nm and a hexagonal aluminophosphate molecular sieve ( HMA); A pore size of 2 to 20 nm and hexagonal silica molecular sieve (MCM-41); And a particle size of 0.2 ~ 2 ㎚ the aluminophosphate molecular sieve (AlPO ₄ -5) minutes selected from themselves and 99.5 - 95 mol%, the transition metal is contained 0.5 to 5.0 mol%, consisting of a heterogeneous catalyst, of 20 to 150 It is characterized by a method for producing tetraralone which is carried out at a stirring temperature in the range of 50 to 1000 rpm for 2 to 12 hours at a temperature of ℃.

That is, the present invention relates to a method for producing tetraral by liquid partial oxidation of tetralin under specific reaction conditions with specific heterogeneous catalysts.

When the tetralin of the present invention in a liquid partial oxidation reaction to explain the method for producing tetralin in more detail as follows.

First, the heterogeneous catalyst of the present invention has a pore size of 2 to 20 nm, a hexagonal aluminophosphate molecular sieve (HMA), a pore size of 2 to 20 nm, and a hexagonal silica molecular sieve (MCM-41). minutes and selected from the group consisting of a pore size of 0.2 ~ 2 ㎚ the aluminophosphate molecular sieve (AlPO ₄ -5) contains its own, and a transition metal.

Molecular sieves and transition metals, such as the aluminophosphate molecular sieve (HMA), silica molecular sieve (MCM-41) and aluminophosphate molecular sieve (AlPO ₄ -5), are commonly used components in the field of catalysts. No technical configuration features However, the present invention is effective in the partial oxidation of tetralin using liquid oxidizing agent and the specific pore size among various molecular sieves applied to the catalyst to effectively introduce the active transition metal component for the reaction into the molecular sieve lattice structure. The molecular sieve having a crystalline structure and a heterogeneous catalyst in which a transition metal is mixed are used after performing a specific washing process to apply the liquid partial oxidation of tetralin. In other words, a heterogeneous catalyst having optimal activity in the liquid phase partial oxidation of tetralin is selected and used.

The molecular sieve of the present invention is capable of introducing a transition metal, which is an active ingredient, into the molecular sieve lattice structure for the partial oxidation of tetralin using a liquid oxidizing agent, specifically, a mesoporous having a pore size of 2 to 20 nm, Hexagonal aluminophosphate molecular sieve (HMA), pore size mesoporous 2-20 nm, hexagonal silica molecular sieve (MCM-41) and pore size 0.2-2 nm microporous aluminophosphate powder You can use your own (AlPO ₄ -5), etc. That is, the molecular sieve of the present invention can introduce a transition metal into the hexagonal silica or zeolite crystal structure. When the transition metal is introduced into the structure, the number and dispersibility of the transition metal in atomic units increases, so that the catalyst activity is excellent. do.

In addition, the transition metal is typically used in the field of liquid partial oxidation, but is not particularly limited. Specifically, a single metal or a mixture of two or more metals selected from chromium, iron, cobalt, manganese, and nickel may be used. Preferably, chromium is used.

The heterogeneous catalyst contains 95 to 99.5 mol% of molecular sieves, preferably 97 to 99 mol%, 0.5 to 5 mol% of transition metals, and preferably 1 to 3 mol%, and thus the amount of the transition metal used is If the amount is less than 0.5 wt%, the amount is too small to show the activity of the catalyst. If it exceeds 5 wt%, the activity cannot be expected to be improved. It is preferable to maintain the above range because the stability of the catalyst is lowered and the transition metal contained in the solvent must be removed.

The heterogeneous catalyst of the present invention is prepared by mixing a transition metal with a synthetic gel component for preparing a molecular sieve by a sol-gel method by a method generally used in the art. In this case, the present invention uses a ionic compound such as ammonium acetate, nitric acid, sulfuric acid and acetic acid to ion exchange or wash the transition metal that is not present in the lattice structure of the prepared catalyst or is introduced in excess. Necessarily including removing the metal. At this time, it is more preferable that the ionic compound uses an ionic organic substance having a small molecular weight.

In general, heterogeneous catalysts have active components such as transition metals in the lattice structure, and the present invention affects the conversion and selectivity of tetranal, which is a result of the liquid partial oxidation of the transition metals in the structure. Mitch acts as a factor. In addition, when the catalyst is reused, the transition metal present in the lattice structure affects the catalytic activity, and in the case of the transition metal existing outside the lattice structure of the molecular sieve, the transition metal is continuously included in the product to decrease the selectivity of tetralon. Since the problem is caused and the catalytic activity is reduced by side reactions, the washing process must be performed to maintain the long-term stability of the catalyst.

The heterogeneous catalyst of the present invention comprises the steps of preparing a catalyst precursor by mixing a synthetic gel containing a molecular sieve precursor and a transition metal precursor for 24 to 72 hours at 25 to 100 ℃, and the catalyst precursor 450 to 650 Firing at 6 ° C. for 6 to 10 hours, and washing in an ammonium acetate solution at a concentration of 0.2 to 3 mol% to prepare a heterogeneous catalyst.

Synthetic gel containing the molecular sieve precursor is not particularly limited in the art to the components and contents used in the manufacture of molecular sieves generally by the sol-gel method. Literature related to the method of preparing the molecular sieve by the sol-gel method is specifically described in Synthesis, characterization and catalytic performance of Mg and Co substituted mesoporous aluminophosphates [Mesopor. Micropor. Mater. 70 (2004) 15], Selective oxidation of hydrocarbons with O ₂ over chromium aluminophosphate-5 molecular sieve [J. Catal. 153 (1995) 1], Synthesis of mesostructured aluminophosphates using cationic templating [Phys. Chem. Chem. Phys. 2 (2000) 5275], Recent advances in processing and characterization of periodic mesoporous MCM-41 silicate molecular sieves [Ind. Eng. Chem. Res. 40 (2001) 3237, Synthesis of thermally stable mesoporous hexagonal aluminophosphate molecular sieves [Chem. Commun. (1997) 1009 and Nanosized metal oxides in the mesopores of MCM-41 and MCM-48 silicates [Catal. Today 68 (2001) 63], and the present invention can be produced by applying this method.

The aging is carried out at 25 ~ 100 ℃ for 24 to 72 hours, if the temperature does not reach each specific region does not form a gel, if not enough time to form a gel and the size and structure of particles It is preferable to maintain the above range because there is a problem.

 In addition, firing is carried out at 450 to 650 ° C. for 6 to 10 hours. If the firing temperature is less than 450 ° C., the surfactants present in the molecular sieve are not completely removed. It may collapse, and if the time is less than 6 hours, it is difficult to sufficiently remove the surfactant and the structural alignment agent, and if it exceeds 10 hours, it is preferable to maintain the above range because there is a problem in the stability of the catalyst.

The ammonium acetate solution used for washing the prepared catalyst has a concentration in the range of 0.2 to 3 mol%, preferably 0.5 to 1.5 mol%, and when the concentration is less than 0.2 mol%, If the removal ability of the transition metal is insignificant and exceeds 3 mol%, there is a problem that there is no further improvement effect and the treatment cost increases. This washing can be repeated one to three times.

Meanwhile, the liquid partial oxidation reaction of the present invention is performed in the presence of an oxidizing agent generally used in the art, and the oxidizing agent may be selected from t-butyl hydroperoxide, air, and oxygen. Such an oxidizing agent is used in the range of 0.1 to 2.5 molar ratio, preferably 1.0 to 2.5, more preferably 1.6 to 2.5 with respect to 1 mole of tetralin as a reactant. If the amount is less than 0.1 molar ratio, the amount is too small to oxidize. It is preferable to maintain the above range because the reaction is not carried out, and even when it exceeds 2.5 moles, the oxidation reaction does not substantially increase and self decomposition of the oxidant occurs.

The liquid partial oxidation reaction of the present invention is preferably carried out for 2 to 12 hours, preferably 8 to 12 hours in the temperature range of 20 to 150 ℃, preferably 80 to 150 ℃. That is, the conventional liquid phase partial oxidation reaction was performed by a homogeneous catalyst, but in general, the liquid phase partial oxidation reaction was performed using a heterogeneous catalyst having a significantly lower activity than that of the homogeneous catalyst. It has the above catalytic activity. In addition, the separation and reuse of the heterogeneous catalyst is excellent, and thus storage stability and process convenience can be obtained.

If the reaction temperature is less than 20 ℃ conversion rate is low, the reaction time should be more than 24 hours in order to obtain a comparable conversion rate, if it exceeds 150 ℃, not only the stability of the transition metal catalyst, but also the decomposition of the oxidizing agent and the reaction product There is a problem that the selectivity of is reduced. In addition, if the reaction time is less than 4 hours and has a low conversion rate and a high selectivity of the by-products similar to the reaction temperature, if it exceeds 12 hours, it is difficult to expect the increase of the conversion rate to reach the equilibrium of the reaction and unnecessary reaction products It is desirable to maintain this range because problems that arise are generated.

This liquid partial oxidation reaction can be carried out in a batch reactor, a continuous batch reactor and a fixed bed reactor generally used in the art.

When the liquid partial oxidation of tetralin is carried out using the heterogeneous catalyst prepared as described above, the catalytic activity is excellent, and thus, the conversion and selectivity of the tetralin is excellent, and in particular, the stability of the catalyst even when the catalyst is reused. Is maintained.

Although this invention is demonstrated concretely based on an Example, this invention is not limited to a following example.

Catalyst manufacturing

Example 1 Mesoporous Aluminophosphate (M-HMA) Molecular Sieve Catalyst

3.5 g of aluminum hydroxide was mixed with 25 g of distilled water and 2.5 ml of a phosphate solution (85 wt% sol in water), followed by stirring for 1 hour. 30 g of distilled water was taken in a separate beaker to dissolve 4 g of cetyltrimetylammonium bromide, added to the solution, and stirred for 3 hours. 2 mol% of the transition metal precursor (based on the transition metal) is added to 15 g of distilled water, and 0.32 g of chromium acetate (III) hydroxide, 0.47 g, is used as the transition metal precursor. Cobalt (II) nitrate hexahydrate and 0.65 g of iron nitrate nanohydrate were used.

Next, 25 ml of tetramethylammonium hydroxide (TMAOH) at 25 wt% was added to adjust the pH of the mixture to 9.5, and aged at room temperature (25 ° C.) for 72 hours. Thereafter, the precipitate was collected by filtration, washed sufficiently with distilled water, and dried in an oven at 80 ° C. The dry powder was calcined at 500 ° C. for 10 hours.

Example 1-1

In the same manner as in Example 1, the chromium acetate hydroxide (based on chromium) was changed to 1, 2, 3, and 5 mol% (0.16 g, 0.32 g, 0.49 g, 0.81 g) as transition metal precursors, respectively. It was carried out while.

Example 2 Mesoporous Silica (M-MCM-41) Molecular Sieve Catalyst

To a solution of 32 g of cetyltrimetylammonium bromide dissolved in 115 g of distilled water, 37.4 g of sodium water glass and 2 mol% of a transition metal precursor (based on a transition metal) were added, followed by stirring for 30 minutes. At this time, 0.62 g of chromium acetate 0.89 g of cobalt nitrate hexahydrate and 1.24 g of iron nitrate nanohydrate were used as the transition metal precursors. Next, 10 g of 2.4 g sulfuric acid (H ₂ SO ₄ , 98%) was diluted with water, and then added to the mixture. Thereafter, the gel formed was aged at 100 ° C. for 24 hours, filtered to recover the precipitate, and then sufficiently washed with distilled water. Next, the precipitate was dried at 100 ° C. for 24 hours and then calcined at 540 ° C. for 10 hours.

Example 3 Microporous Aluminophosphate (M-AlPO4-5) Molecular Sieve Catalyst

In 20 g of distilled water, 4.0 g of pseudobohemite was dissolved. Thereafter, 2 mol% of a transition metal precursor (based on chromium, cobalt, and iron) was added, followed by stirring for 2 hours. At this time, the amount of the transition metal precursor used was 1.75 g for chromium acetate, 0.6 g for cobalt nitrate, and 0.98 g for iron (III) sulfate, respectively. Separately, 7.4 g of aluminum isopropoxide was added to 20 g of distilled water, followed by stirring for 2 hours.

The pseudoboehmite solution and the aluminum isopropoxide solution containing the transition metal were stirred for 2 hours and then aged for 1 hour after adding 85% phosphoric acid. After adding 7.16 g of tripropylamine to the mixture, the synthetic gel was transferred to an autoclave and hydrothermally synthesized at 175 ° C. for 24 hours. Thereafter, the precipitate was collected by filtration, washed sufficiently with distilled water, and then dried at 100 ° C. and calcined at 500 ° C. for 10 hours.

Example 3-1

In the same manner as in Example 3, the chromium acetate hydroxide (based on chromium) was changed to 1, 2, 3 and 5 mol% (0.85 g, 1.75 g, 2.65 g and 4.5 g), respectively, as the transition metal precursor. It was carried out while.

Liquid Partial Oxidation of Tedralline

Example  4

50 mg of each catalyst prepared in Examples 1 to 3 was accurately weighed and placed in a 100 ml glass batch reactor (Chemistation PPS-2510) equipped with a thermostat, a mechanical stirrer and a condenser. As a reactant, 8 mmol of tetralin was mixed with 5 ml of chlorobenzene as a solvent to make a uniform solution. After the reaction temperature reached 120 ° C., 16 mmol of t-butyl hydroperoxide (Aldrich, 5.5M, decane balance) was added to the reaction product through an septum as an oxidant.

The reactants and products were analyzed using a gas chromatograph (HP-5 capillary column) equipped with a flame ionization detector (FID), and detailed reactant analysis was performed using GC-MS.

The tetralin partial oxidation activity of the catalysts is shown in Table 1. At this time, the reaction activity was measured after 12 hours.

As shown in Table 1, among the transition metals, the introduction of chromium showed the highest tetralin conversion and selectivity to tetralin as the target product on all molecular sieves. Specifically, when chromium is introduced, it can be seen that activity and selectivity according to molecular sieves are shown in the order of mesoporous aluminophosphate (HMA) ≥ aluminophosphate (AlPO4-5) >> mesoporous silica (MCM-41).

Example 5 Liquid Partial Oxidation with Chromium Content (Cr-HMA Catalyst)

In the same manner as in Example 4, the tetralin partial oxidation activity and selectivity according to the chromium content in the Cr-HMA catalyst prepared in Example 1-1 is shown in Table 2.

As shown in Table 2, when the amount of chromium introduced was 2 mol% than the 1.0 mol%, the conversion rate and the tetralin selectivity were increased, but at 2.0 mol% or more, the conversion rate was almost constant, about 65%. The loan selection was also maintained at about 80%.

Example 6 Liquid Partial Oxidation Reaction According to Reaction Time of Catalyst (Cr-HMA)

In the same manner as in Example 4, in the Cr-HMA catalyst prepared in Example 1 (chromium content 2 mol%), the tetralin liquid phase partial oxidation reaction activity and selectivity according to reaction time are shown in Table 3.

As shown in Table 3, when 2 hours after the start of the reaction, the tetralin conversion was about 23%, and the tetralin selectivity was 51%. The conversion rate gradually increased with the reaction time, and after 12 hours, the conversion rate was equilibrated at 65% and the tetranal selectivity was 80%.

Example 7 Liquid Phase Partial Oxidation According to Reaction Temperature of Catalyst (Cr-HMA)

In the same manner as in Example 4, the tetralin partial oxidation activity and selectivity according to the reaction temperature in the Cr-HMA catalyst (chromium content 2 mol%) prepared in Example 1 is shown in Table 4. At this time, the reaction temperature was adjusted to 20 ~ 120 ℃ and compared with the conversion and selectivity after 8 hours.

As shown in Table 4, as the reaction temperature increases, the tetralin conversion was increased, but the tetralin selectivity did not change significantly even at an increase in temperature above 80% at 80 ° C. Therefore, it was confirmed that the tetralin partial oxidation reaction should be carried out at a reaction temperature of at least 80 ℃.

Example 8 Liquid Partial Oxidation According to Oxidizer Concentration

In the same manner as in Example 4, the tetralin partial oxidation activity according to the molar ratio of tert-butyl hydroperoxide (TBHP) and tetralin in the Cr-HMA catalyst (chromium content 2 mol%) of Example 1 and Selectivity is shown in Table 5. At this time, the reaction temperature was 120 ℃, conversion and selectivity were measured after 8 hours of reaction.

As shown in Table 5, as the oxidizer / tetralin molar ratio increases, the tetralin conversion increases. The molar ratio shows an equilibrium value at 2.0, and the tetralin selectivity shows the opposite trend to the conversion. . Therefore, the tetralin partial oxidation reaction was confirmed that the oxidizing agent / tetralin molar ratio should be carried out at least 1.6.

Example 9 Stability in Catalyst Reuse by Ammonium Acetate Treatment

In order to remove the poly-chromates present in outer lattice structure of the first embodiment of the catalyst _{Cr-HMA (Cr-AlPO 4} -5) produced in treated and washed with the ammonium acetate. 100 mg of the catalyst was mixed with 1M ammonium acetate solution and stirred at room temperature for 12 hours. After that, the ammonium acetate solution and the catalyst were separated using a centrifuge and washed well with distilled water. In this case, when the amount of the catalyst is large, it is good to perform separation and washing using filter paper. The separated and washed catalyst was dried in an oven at 100 ° C. for 12 hours and then calcined at 500 ° C. for 6 hours to remove the residue.

Separately, the catalyst participating in the reaction was recovered using a centrifuge. At this time, if the amount of the catalyst is separated by using a filter paper, the recovered catalyst using acetone solution is sufficiently washed and dried in an oven at 80 ℃ for 12 hours. It was calcined at 500 ° C. for 6 hours to remove the residue.

Thereafter, the reaction was performed in the same manner as in Example 4, and the conversion and selectivity after 8 hours were shown in Table 6.

As shown in Table 6, in the case of Cr-HMA (Cr-AlPO4-5) catalyst, when the ammonium acetate treatment was not performed, the conversion rate of the first 57.6% was 48.5% when the second reuse was decreased by about 15.8%. When the Cr-AlPO4-5 catalyst was treated with ammonium acetate, the conversion was reduced from 57.6% to 52.9% due to the removal of polychromates outside the lattice structure, but the conversion was 50.8 even when the catalyst was reused twice. In%, the activity of about 2.1% was reduced, indicating that the catalyst treated with ammonium acetate showed higher catalytic activity stability than the catalyst without.

Therefore, when applied to the liquid partial oxidation of tetralin, the activity of the catalyst washed with ammonium acetate after firing was similar to that of the untreated catalyst, and it was confirmed that the activity was maintained stably, especially when reused.

Claims (5)

In a method for producing tetraral by liquid partial oxidation of tetralin in the presence of a catalyst and an oxidizing agent, Examples of the catalyst include aluminophosphate molecular sieves (HMA) having a pore size of 2 to 20 nm, hexagonal silica molecular sieves (MCM-41) having a pore size of 2 to 20 nm, and 0.2 to 2 particle sizes. A synthetic gel containing a molecular sieve precursor selected from nm aluminophosphate molecular sieves (AlPO ₄ -5) and a transition metal precursor are mixed in an amount ratio of 95 to 99.5 mol% of the molecular sieve and 0.5 to 5.0 mol% of the transition metal. To mature at 25 to 100 ℃ to prepare a catalyst precursor; And calcining the catalyst precursor at 450 to 650 ° C. and washing the catalyst precursor with an ammonium acetate solution at a concentration of 0.2 to 3 mol% to prepare a heterogeneous catalyst. By using a heterogeneous catalyst prepared by Tetraline is prepared by performing a liquid partial oxidation reaction at a stirring speed in the range of 50 to 1000 rpm for 2 to 12 hours at a temperature of 20 to 150 ℃. delete The method of claim 1, wherein the transition metal is a single metal or a mixture of two or more metals selected from chromium, iron, cobalt, manganese, and nickel. The method of claim 1, wherein the oxidizing agent is one or a mixture of two or more selected from t-butyl hydroperoxide, air, and oxygen, and is used in a molar ratio of 0.1 to 2.5 with respect to 1 mole of tetralin. . The process according to claim 1, wherein the reaction is carried out in a batch reactor, a continuous batch reactor, or a fixed bed reactor.