JP4791246B2 - Glycerin dehydration catalyst and method for producing acrolein - Google Patents

Description

  The present invention relates to a glycerol dehydration catalyst, and more particularly to a glycerol dehydration catalyst suitable for acrolein production by dehydration of glycerin.

  Biodiesel produced from vegetable oil is attracting attention not only as a substitute for fossil fuels but also because it emits less carbon dioxide, and demand is expected to increase. When this biodiesel is produced, glycerin is produced as a by-product, so it is necessary to make effective use of it. One embodiment of the use of glycerin includes the use of glycerin as a raw material for acrolein.

Methods for producing acrolein using glycerin as a raw material are disclosed in, for example, Patent Document 1 and Non-Patent Document 1. Patent Document 1 discloses that H-MFI having an acid strength function of +2 or less is used to dehydrate glycerin to produce acrolein, but this disclosed method is useful for liquid phase dehydration. Patent Document 1 describes that it is not useful in vapor phase dehydration. The other Non-Patent Document 1 discloses that a gas phase dehydration reaction of glycerin was performed using a catalyst. The catalyst disclosed in Non-Patent Document 1 is composed of 20% by mass of bentonite and 80% by mass of H-MFI, and H-MFI that is a catalyst configuration contains 0.55% by mass of Na ₂ O. .

As disclosed in Patent Document 1 and Non-Patent Document 1, acrolein can be produced by a glycerin dehydration reaction using a catalyst. In this case, if there is little change in the acrolein yield with time, it is easy to make a production plan. It is expected that the shortage and excess of acrolein production can be prevented. In addition, if acrolein can be produced in high yield, acrylic acid, 1,3-propanediol, allyl alcohol, polyacrylic acid, polyacrylic acid salt, methionine, which are conventionally known to be produced using acrolein as a raw material, are known. It is expected that acrolein derivatives such as these can be produced at low cost.
Japanese Patent Laid-Open No. 06-211724 Le H. Dao, Reaction of Model Compounds of Biomass-Pyrolysis Oils Over ZSM-5 Zeolite Catalysts, American Chemical Society, 1988, 376, p.328-341

  In view of the above circumstances, an object of the present invention is to provide a catalyst for glycerol dehydration that suppresses a change in acrolein yield over time.

  In the catalyst having an acidic crystalline metallosilicate that can dehydrate glycerin, the Si / T is within a predetermined range, and the amount of the binder is limited, the acrolein yield changes with time. The inventors have found that it can be suppressed, and have completed the present invention.

  That is, the present invention is for dehydrating glycerin having a crystalline metallosilicate containing one or more T atoms selected from Al, B, Ti, Cu, In, Cr, Fe, Co, Ni, Zn, and Ga. A catalyst for glycerin dehydration, characterized in that Si / T in the crystalline metallosilicate is 800 or less and the binder amount in the catalyst is 15% by mass or less.

  In the catalyst of the present invention, the upper limit of the binder content is 15% by mass, but if the binder is included, the crystalline metallosilicate showing catalytic activity may be diluted and the yield of acrolein may be reduced. It is preferable not to have.

The crystalline metallosilicate preferably has H ⁺ as a cation outside the crystal lattice. In addition to suppressing the yield change of acrolein, in order to produce acrolein with high yield, the T atom is preferably Al, and the crystalline metallosilicate is of MFI type. It preferably has a crystal structure.

In the catalyst, in order to increase the yield of acrolein, it is preferable that the content of Na converted to Na ₂ O is 1.0% by mass or less.

  If the catalyst is used, not only when acrolein is produced by a liquid phase dehydration reaction of glycerin but also when acrolein is produced by a gas phase dehydration reaction of glycerin, it is possible to suppress a time-dependent change in acrolein yield. .

  Further, the present invention is a method for producing acrolein by dehydrating glycerin in the presence of the catalyst according to the present invention. In this method, glycerin may be dehydrated by a gas phase reaction in which glycerol and a catalyst are brought into contact with each other.

  Moreover, this invention is a manufacturing method of the acrolein derivative which has the process of manufacturing acrolein using the manufacturing method of the acrolein which concerns on the said this invention. Examples of the acrolein derivative that can be produced by this method include acrylic acid, 1,3-propanediol, allyl alcohol, methionine, polyacrylic acid, and sodium polyacrylate that are conventionally produced using acrolein as a raw material. Mention may be made of polyacrylates.

  According to the glycerol dehydration catalyst of the present invention, Si / T is in a predetermined range, and an upper limit value of the binder amount is provided, so that acrolein can be produced while suppressing a yield change.

  The present invention will be described below based on embodiments. The catalyst of the present embodiment is a glycerol dehydration catalyst having a crystalline metallosilicate. This catalyst is configured as a molded body in which a plurality of metallosilicate crystals are assembled.

The catalyst preferably has a Na content in terms of Na ₂ O of 1.0% by mass or less. A catalyst in this concentration range is excellent in acrolein yield. Since the acrolein yield tends to increase as the amount of Na ₂ O decreases, the amount of Na ₂ O is more preferably 0.05% by mass or less, and still more preferably 0.01% by mass or less.

The pore diameter (secondary pore diameter) of the catalyst of the present embodiment is not particularly limited, but may be 0.80 μm or less, preferably 0.08 to 0.40 μm excellent in acrolein yield. It is. The mode diameter is 6.9 to 4.1 × 10 ⁵ kPa (1 to 60000 psia ) in absolute pressure , the contact angle is 130 °, the mercury surface tension is 485.0 mN / m, and the mercury density is 13.5335 g. It is a measured value by a mercury intrusion method that can be measured when it is / cm ³ . In addition, regarding the catalyst in the present embodiment, the acrolein yield hardly depends on the pore size (primary pore size) of the crystalline metallosilicate.

The specific surface area of the catalyst is not particularly limited, as measured by nitrogen adsorption according to the BET method, well with a 300~550m ² / g, preferably from 315~500m ² / g.

The crystalline metallosilicate in the present embodiment is a crystal in which regular tetrahedral structure SiO ₄ and TO ₄ are used as basic structural units, and these SiO ₄ and TO ₄ are three-dimensionally connected. As the crystalline metallosilicate in the catalyst of the present embodiment, the metallosilicate of the crystal structure classified by the structure code of the International Society of Zeolite Society, and “ZEOLITES, Vol. 12, No. 5, 1992” and “ Metallosilicates having the structure described in “HANDBOOK OF MOLECULAR SIEVES, R. Szostak, VAN NOST RAND REINHOLD publication” and the like can be mentioned, and the crystal structure is not particularly limited. When this crystalline metallosilicate is illustrated based on the name of the International Zeolite Society Structural Committee, the inlet of the pore of LTA, CHA, ERI, KFI, etc. is a crystalline metallosilicate with an 8-membered oxygen ring; FER, MFI, etc. Crystalline metallosilicate with a 10-membered oxygen ring at the entrance of the pore; Crystalline metallosilicate with a 12-membered oxygen ring at the pore entrance of MOR, BEA, FAU, LTL, GME, OFF, MTW, etc. Among the exemplified crystalline metallosilicates, MFI capable of producing acrolein with high yield is preferable.

The crystalline metallosilicate has a cation capable of ion exchange outside the crystal lattice. The metallosilicate crystal lattice cation in the present embodiment includes H ⁺ , Li ⁺ , Na ⁺ , Rb ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , Sc ³⁺ , Y ^{3. +} , La ^{3+ and the} like can be exemplified. In particular, H-type crystalline metallosilicates in which some or all of the extra-lattice cations are H ⁺ are suitable.

The T atom in the structural unit TO ₄ of the crystalline metallosilicate is an atom excluding Si, and one or two selected from Al, B, Ti, Cr, Fe, Co, Ni, Cu, Zn, Ga, and In More than species. Among these T atoms, it is preferable that Al, B, Fe, Ga, and In are selected, and it is more preferable that Al is selected.

  The molar ratio Si / T between Si atoms and T atoms in the crystalline metallosilicate is 800 or less. When Si / T exceeds 800, the acrolein yield changes with time, or the acrolein yield becomes extremely low. Moreover, preferable Si / T for suppressing the time-dependent change of an acrolein yield is 10-600. On the other hand, the preferred Si / T for producing acrolein in high yield is 10 to 400, more preferably 20 to 300.

  The crystallinity of the crystalline metallosilicate is preferably 85% or more, more preferably 95% or more, and still more preferably 98% or more.

There is a T atom that is not incorporated in the crystal lattice of the crystalline metallosilicate (hereinafter, “T atom that is not incorporated in the crystal lattice of the crystalline metallosilicate” may be referred to as “hetero atom outside the crystal lattice”). Crystalline metallosilicates in which heteroatoms are present and crystalline metallosilicates in which heteroatoms are present outside the crystal lattice are crystalline metallosilicates in which heteroatoms are present outside the crystal lattice, even if both crystalline metallosilicates have the same Si / T. Since is more thermally unstable, the content of heteroatoms outside the crystal lattice in the crystalline metallosilicate is preferably limited. In addition, the T atom incorporated in the metallosilicate crystal lattice becomes the active site of the glycerin dehydration reaction, but the same Si / T crystal heterohetero atom exists in the crystalline metallosilicate and the crystal lattice hetero atom exists. In crystalline metallosilicates, the amount of active sites varies, so the content of heteroatoms outside the crystal lattice in the crystalline metallosilicate is preferably limited. For example, when the T atom is Al, the content of metallosilicate out-of-lattice aluminum in the catalyst is preferably 3% by mass or less, preferably 2% by mass or less, and cannot be detected by an analytical instrument ( More preferably, it is not substantially included). This out-of-crystal aluminum content can be calculated by measuring the out-of-crystal aluminum in which oxygen is normally six-coordinated and the in-crystal aluminum in which oxygen is four-coordinated by ²⁷ Al MAS-NMR. That is, the area of the peak measured in the range of σ = 50 to 70 ppm attributed to tetracoordinated aluminum and the area of the peak measured in the range of σ = 0 to 10 ppm attributed to hexacoordinated aluminum were determined. The content of aluminum outside the crystal lattice can be calculated based on the area ratio.

  When the glycerol dehydration reaction is industrially performed using the catalyst of the present embodiment, the molded crystalline metallosilicate may be used as a catalyst. As the catalyst in this case, a molded body composed of a binder and a crystalline metallosilicate or a molded body composed only of a crystalline metallosilicate can be used. When the molded body in the catalyst has a binder, the amount of binder and the acrolein yield change with time are correlated, and the amount of binder in the catalyst is preferably 15% by mass or less. The smaller the amount of the binder, the more the variation of the acrolein yield is suppressed. Therefore, the amount of the binder is more preferably 10% by mass or less, and further preferably 5% by mass or less. The optimum binder amount is 0% by mass. That is, a crystalline metallosilicate molded article which does not have a binder and is not diluted with a crystalline metallosilicate exhibiting catalytic activity is optimal.

  Here, the “binder” when the catalyst has a binder refers to a sinterable inorganic compound existing between adjacent metallosilicate crystals. Examples of suitable binders in this embodiment include inorganic sinterable oxides such as silica, alumina, and titania; and clay minerals such as bentonite and activated clay. In addition, when the clay mineral is used as the binder, one or more cations belonging to alkali metals and alkaline earth metals may be included in the composition. In this case, the number of moles of ion exchange sites of the formed crystalline metallosilicate is the number of moles of cations contained in the clay mineral (however, the number of moles of ½ times the number of moles contained in the alkaline earth metal). If it is not more than the number), the dehydration reaction of glycerin is inhibited by excess cations, which is not preferable.

  Next, the manufacturing method of the catalyst for glycerin dehydration of this embodiment is the first catalyst manufacturing method for preparing a crystalline metallosilicate molded body by adding a binder component to the crystalline metallosilicate particles, and without adding the binder component. Description will be made based on a second catalyst production method for preparing a crystalline metallosilicate molded article.

  First, a first catalyst production method for preparing a crystalline metallosilicate molded body by adding a binder component to crystalline metallosilicate particles will be described. The first catalyst production method is a simple method in which crystalline metallosilicate particles are bound with a binder and molded into a desired shape. In this method, a commercially available crystalline metallosilicate particle, a crystalline metallosilicate particle synthesized by a known method such as a hydrothermal synthesis method, or a crystalline metallosilicate particle produced by a second catalyst production method described later is used as a material crystallinity. It is good to use as metallosilicate particles. Moreover, it is good to use inorganic binders, such as a silica and an alumina, for a binder.

Next, a second catalyst production method for preparing a crystalline metallosilicate molded body without adding a binder component will be described. “Do not add a binder component” in the present method means that a binder component is not added after the crystalline metallosilicate is prepared. This production method is a method for producing a metallosilicate having an MFI structure having a fine crystal particle size and high catalytic activity. The production method includes a supporting step of supporting a predetermined component on the formed silica, a crystallization step of synthesizing a metallosilicate having an MFI structure by bringing the silica after the supporting step into contact with water vapor, and an NH ₄ type MFI metallosilicate. It consists of an ion exchange process to manufacture and a firing process to manufacture H-type MFI metallosilicate. This manufacturing method is demonstrated below for every process.

  In the supporting step, an aqueous solution containing a predetermined component (hereinafter referred to as “impregnating liquid”) is impregnated into a silica molded body, and then the silica molded body is dried to produce a metallosilicate precursor.

  The silica molded body used in the supporting step is not particularly limited. A commercially available silica molded body may be used. Further, the shape and size of the molded body are not particularly limited. Examples of the shape of the molded body include a spherical shape, a cylinder shape, and a ring shape. The size is usually 0.5 to 10 mm in diameter.

  Further, the mechanical strength of the silica molded body is not particularly limited, but it is preferably 9.8 N or more (an average value of 10 silica molded bodies) when measured with a Kiya hardness meter. It is preferable in it being 8-490N. Since the mechanical strength of the silica molded product has a correlation with the mechanical strength of the glycerol dehydrating catalyst to be produced, if a high mechanical strength silica molded product is used, a glycerin dehydrating catalyst having strength that can withstand practical use is produced. can do.

  The predetermined component contained in the impregnating liquid is one to three of T atom component, tetraalkylammonium component, and alkali metal component. The content of the predetermined component in the impregnating liquid is appropriately set according to the amount carried on the silica molded body.

  When the impregnating liquid contains a T atom component, the impregnating liquid contains one or more T atom components selected from Al, B, Ti, Cu, In, Cr, Fe, Co, Ni, Zn, and Ga. It is good to include. For example, when producing an aluminosilicate in which the T atom is aluminum, an Al atom-containing compound such as aluminate, aluminum nitrate, aluminum sulfate, aluminum halide, or aluminum hydroxide may be used as the T atom component. Preference is given to using sodium acid. Further, when producing a methanosilicate having B, Ti, Cu, In, Cr, Fe, Co, Ni, Zn, or Ga as a T atom, boric acid, titanium chloride, copper nitrate, nitric acid containing the corresponding T atom. Indium, chromium nitrate, iron nitrate, cobalt nitrate, nickel nitrate, zinc nitrate, or gallium nitrate may be used as the T atom component.

  The amount of the T atom component in the impregnation liquid is set to an amount corresponding to Si / T of the crystalline metallosilicate that is the production target.

  When the tetraalkylammonium component is contained in the impregnation liquid, for example, tetramethylammonium, tetraethylammonium, tetra-n-propylammonium, tetraisopropylammonium, tetra-n-butylammonium, tetra-n-pentylammonium, It is preferable to use halides or hydroxides such as triethylmethylammonium, triethyl-n-propylammonium, tri-n-propylmethylammonium, tri-n-butylmethylammonium. In order to efficiently synthesize an aluminosilicate having an MFI structure, it is preferable to use a tetraalkylammonium compound having a tetraalkylammonium whose alkyl group has 1 to 5 carbon atoms in its structure. It is more preferable to use a tetraalkylammonium compound having propylammonium as a constituent, and it is most preferable to use tetra-n-propylammonium hydroxide.

  And when making an impregnation liquid contain an alkaline component, it is good to contain hydroxides and halides, such as lithium, sodium, and potassium, in an impregnation liquid. In addition, when a sodium component is contained, it is preferable to contain sodium aluminate which also becomes a T atom component.

  When impregnating the impregnating liquid into the silica compact, all of the T atom component, tetraalkylammonium component, and alkali metal component are impregnated and supported on the silica compact. When the impregnating solution does not contain all of the T atom component, tetraalkylammonium component, and alkali metal component, the impregnation operation is divided into multiple times to remove all of the T atom component, tetraalkylammonium component, and alkali metal component. You may make it support on a molded object. In this way, when the T atom component or the like is loaded in a plurality of times, the loading order of the T atom component or the like does not affect the catalyst to be manufactured.

  The total amount of the impregnating liquid impregnated into the silica molded body is preferably an amount corresponding to the amount that the silica molded body can absorb water.

  The silica molded body after impregnation may be dried under reduced pressure and normal pressure, or may be performed under a normal pressure air stream. In the drying of the silica molded body, in order to suppress elution of the supported component in the crystallization process of the next step, it is preferable to dry until the water content in the silica molded body is 30% by mass or less. It is preferable to carry out drying until it reaches to%. And the drying temperature at this time is good in the range of 20-120 degreeC with few decomposition | disassembly of tetraalkylammonium, Preferably, it is 50 degreeC or more.

  By drying the silica molded body, a metallosilicate precursor which is a production object of the supporting process is obtained. Since the metallosilicate precursor is a silica molded body that is dried after the impregnation liquid is contained, the T atom component, the tetraalkylammonium component, and the alkali metal component are uniformly supported.

The dried silica molded article carries a T atom component and the like, which becomes a metallosilicate precursor. The composition of this precursor is represented by the following formula (1).
Si ₁ TxMy (SDA) z (1)
In formula (1), M is an alkali metal, SDA is a tetraalkylammonium, x is 0.00125 or more (preferably 0.00167 to 0.1, more preferably 0.0025 to 0.1, still more preferably 0.00. 0033 to 0.05), y is 0.0001 to 1 (preferably 0.0005 to 0.5), z is 0.001 to 1 (preferably 0.002 to 1, more preferably 0.003). ~ 0.8). Here, when the composition ratio (y) of the alkali metal (M) is too small, the hydrolysis of the silica does not proceed, and the conversion to the crystalline metallosilicate in the crystallization step hardly occurs, while the alkali metal (M If the composition ratio (y) is too large, the silica is too hydrolyzed and the silica compact is dissolved. Therefore, the numerical range of y is as described above. On the other hand, when the composition ratio (z) of tetraalkylammonium (SDA) is too small, silica hydrolyzed in the crystallization process is hardly built into a crystalline metallosilicate, while the composition ratio (z of tetraalkylammonium (SDA)) ) Is excessive, tetraalkylammonium is wasted, and the impregnating solution may become highly viscous, making it difficult to build a crystalline metallosilicate. Therefore, the numerical range of z is as described above.

  The crystallization step is performed by contacting the metallosilicate precursor with saturated steam. In this crystallization step, the heat of condensation of water vapor in the pores of the precursor advances the hydrolysis of silica, silica crystals containing aluminum are built around SDA, and the metallosilicate precursor is converted to MFI. This crystallization step is a step of placing a metallosilicate precursor in saturated steam, unlike a general hydrothermal synthesis method as a method for producing a metallosilicate, so that the shape of the metallosilicate precursor is maintained, and Si It is possible to synthesize a metallosilicate having an MFI crystal structure while suppressing the elution of T and T atoms from the metallosilicate precursor.

  In the crystallization step, saturated steam is brought into contact with the metallosilicate precursor as described above. As this contact method, for example, (1) a metallosilicate precursor is placed in a hollow portion of a pressure vessel, water corresponding to a saturated water vapor amount determined by temperature and volume of the vessel is injected into the lower portion of the pressure vessel, and then sealed. (2) Use a double container composed of an inner container and an outer container, install a metallosilicate precursor in the inner container, and put water in the outer container There are a method in which the double container is sealed and heated to bring the aluminosilicate precursor into contact with water vapor, and (3) a moving bed method in which the metallosilicate precursor is continuously fed into saturated water vapor.

  The temperature in the crystallization step is not particularly limited as long as the metallosilicate precursor is converted to MFI, but MFI having a high degree of crystallinity with little decomposition of the tetraalkylammonium supported on the precursor. It is good that it is 80-260 degreeC which can be manufactured. A preferred temperature is 100 to 230 ° C. The time for which the silica molded body is brought into contact with saturated water vapor is preferably 2 hours or more in order to sufficiently advance the crystallinity. The upper limit of time is preferably within 150 hours in order to suppress mixed crystallization with crystals other than MFI.

  The metallosilicate having the MFI structure obtained through the crystallization step can be usually a crystalline metallosilicate having a crystallinity of 85% or more as long as the temperature and time in the above crystallization step. In the crystallization step, a crystalline metallosilicate having a crystallinity of 98% or more can be produced by adjusting the temperature and time. Here, the longer the contact time with saturated water vapor, the higher the crystallinity, and conversely, the shorter the time, the lower the crystallinity, so that the degree of crystallinity can be adjusted. Therefore, by setting the contact time with saturated steam to a long time, a crystalline metallosilicate having a crystallinity of 100% substantially free of binder can be produced.

In the ion exchange step, NH ₄ type crystalline metallosilicate is produced by ion exchange of M atom of M type crystalline metallosilicate (M represents an alkali metal such as Na) synthesized in crystallization step with NH _4. Is done. This ion exchange is performed by immersing the M-type crystalline metallosilicate in an NH ₄ aqueous solution.

As the NH ₄ aqueous solution to be used, an aqueous ammonium salt solution such as ammonium nitrate or ammonium chloride is used. When the NH ₄ concentration in the aqueous solution is too low, the ion exchange time becomes long, and when a high concentration aqueous ammonium salt solution is used, the ammonium salt that is not ion-exchanged is wasted. Therefore, in this aqueous solution, NH ₄ is preferably equivalent to 100 times equivalent to the exchange capacity and the ammonium salt concentration is 0.01 to 5.0 mol / L. Preferably, NH ₄ is 2 to 30 times equivalent and the ammonium salt concentration is 0.05 to 2.0 mol / L.

  The temperature of the aqueous ammonium salt solution in the ion exchange step is preferably room temperature or higher and lower than 100 ° C. If the temperature of the aqueous ammonium salt solution is high, the ion exchange rate can be increased, but if it is 100 ° C. or higher, the evaporation of water is fast, and a pressure vessel for suppressing the evaporation of water is required. Absent. On the other hand, if the temperature of the aqueous ammonium solution is low, the ion exchange rate is undesirably slowed.

  The immersion time in the ion exchange step is 15 minutes to 6 hours, preferably 30 minutes to 2 hours. When this time is short, the exchange of M atoms in the metallosilicate does not end, and when the time is long, the ion exchange cannot proceed beyond a certain level due to the exchange equilibrium.

This ion exchange step is performed by immersing the M-type crystalline metallosilicate in an aqueous ammonium salt solution. In order to efficiently exchange M atoms of the crystalline metallosilicate with NH ₄ while suppressing ion exchange inhibition due to equilibrium. It is preferable to repeatedly perform immersion and replacement or exchange of the aqueous ammonium salt solution.

In the second catalyst production method of the present embodiment, the M atom of the M-type crystalline metallosilicate is ion-exchanged with NH ₄ , but an aqueous metal acid such as hydrochloric acid or nitric acid is used for the metallosilicate. It is also possible to exchange M atoms for H atoms. In this case, the conditions such as the concentration of the mineral acid and the temperature of the aqueous solution are preferably the same as the ion exchange using the ammonium salt. Regarding the concentration of the mineral acid, if the concentration is high, the mineral acid that is not ion-exchanged is not only wasted, but the metallosilicate may be destroyed.

In the final firing step, NH ₄ type crystalline metallosilicate produced in the ion exchange step is converted to H type crystalline metallosilicate. Along with this conversion, residual organic substances in the metallosilicate burn and disappear.

The firing step may be performed under an air stream. If the calcination temperature is too low, organic matter and NH ₄ may remain, and if the calcination temperature is too high, the metallosilicate crystals may be destroyed. Therefore, the calcination temperature is preferably 350 to 600 ° C. Further, if the firing time is too short, organic matter and NH ₄ may remain, and if the firing time is too long, the crystals may be destroyed. Therefore, the firing time is preferably 2 to 10 hours.

  The second catalyst production method is as described above. The catalyst produced by this second catalyst production method has a crystallinity of 85% or more. In the catalyst produced by the second catalyst production method, the content of heteroatoms outside the MFI crystal lattice relative to the total amount of T atoms in the MFI crystal lattice and heteroatoms outside the MFI crystal lattice is 3% by mass or less.

  The above-mentioned second catalyst production method is for producing a metallosilicate having an MFI structure. To produce a catalyst comprising a crystalline metallosilicate other than MFI, JP-A-2001-180928 is disclosed. The catalyst may be produced using a known method disclosed in JP 2001-139324 A, JP 2001-114512 A, or the like.

  Next, a method for producing acrolein using the catalyst of the present embodiment will be described. The method for producing acrolein in the present embodiment is to produce acrolein by a gas phase dehydration reaction in which a reaction gas containing glycerin is brought into contact with a catalyst in a reactor arbitrarily selected from a fixed bed reactor, a moving bed reactor and the like. It is. The catalyst according to the present invention is not limited to an acrolein manufacturing method in which a reaction gas and a catalyst are brought into contact with each other, and can also be used in a manufacturing method in which a glycerin solution and a catalyst are brought into contact with each other. In this case, a fluidized bed reactor or the like is selected as the reactor.

  The reaction gas may be a gas composed only of glycerin, and may contain an inert gas in the glycerin dehydration reaction in order to adjust the glycerin concentration in the reaction gas. Examples of the inert gas include water vapor and nitrogen gas. The glycerin concentration in the reaction gas is preferably 0.1 to 100 mol%, preferably 1 mol% or more, and 10 mol% or more in order to produce acrolein economically and highly efficiently. .

Since the catalyst is a highly efficient glycerol dehydration catalyst, acrolein can be obtained in a high yield even when the flow rate of the reactive gas is set to be large. The flow rate of the reactive gas is preferably 100 to 10,000 hr ⁻¹ in terms of the reactive gas flow rate (GHSV) per unit catalyst volume. Preferred is a 5000 hr ^-1 or less, in order to perform the production of acrolein economically and efficiently is 3000 hr ^-1 or less.

  The reaction temperature may be 200 to 500 ° C, preferably 250 to 450 ° C, and more preferably 300 to 400 ° C.

  The pressure of the reaction gas is not particularly limited as long as the pressure is within a range where glycerin does not condense. Usually, it is good that it is normal-pressure-1MPa, Preferably, it is 0.5 MPa or less.

  Acrolein can be produced by the above method. The produced acrolein can be used as a raw material for producing acrolein derivatives such as acrylic acid, 1,3-propanediol, allyl alcohol, polyacrylic acid, polyacrylate, methionine and the like as already known. Therefore, it is naturally possible to incorporate the acrolein production method described above into the acrolein derivative production method.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to the following examples, and may be appropriately modified and implemented within a range that can meet the purpose described above and below. All of which are within the scope of the present invention.

Example 1
By carrying out the following supporting step, crystallization step, and ion exchange step, the catalyst of each example and comparative example (crystalline methanosilicate molded body in which T atoms are Al) was produced.

(Supporting process)
0.58 g of NaOH and 1.95 g of NaAlO ₂ were sequentially dissolved in 15.00 g of distilled water, and 10.15 g of 40 mass% tetra-n-propylammonium hydroxide aqueous solution was added to the distilled water. Then, distilled water was added to this solution to prepare an impregnating solution having a total amount of 30 ml.

  Next, silica beads ("Caractect Q-50" manufactured by Fuji Silysia Chemical Ltd., 10 to 20 mesh, average pore diameter 50 nm) are used as the silica molded body, and impregnated with 30 g silica beads dried at 120 ° C for 1 day. The liquid was impregnated for 1 hour. Thereafter, the silica beads were dried on an evaporating dish placed on a 100 ° C. hot water bath, and further dried at 80 ° C. under a nitrogen stream for 5 hours to obtain Na and Al crystallizing agents necessary for crystallization. A crystalline methanosilicate precursor was obtained by supporting it on beads.

(Crystallization process)
The precursor obtained in the supporting step is placed in the hollow part of a tetrafluoroethylene jacketed crucible having a volume of 100 ml, and 1.00 g of distilled water is placed at the bottom of the crucible, and this crucible is placed in an electric furnace at 180 ° C. for 8 hours. Left to stand.

(Ion exchange process)
The solid after the crystallization step was immersed in 300 g of a 1 mol / L aqueous ammonium nitrate solution at 60 ° C. and stirred for 1 hour, and then the supernatant was discarded. This operation was repeated several times. Thereafter, the solid was washed with water.

(Baking process)
The solid after the ion exchange step was baked at 540 ° C. for 3.5 hours in an air stream. By this calcination, an H-type MFI catalyst of Example 1 was obtained.

(Example 2)
A crystalline metallosilicate powder (NH ₄ type MFI “5524G” manufactured by ZEOLYST, T atom: Al) was pressure-molded, coarsely pulverized, and then classified. This classified 0.7-2.0 mm crystalline metallosilicate was calcined in an air stream at 540 ° C. for 3 hours to obtain an H-type MFI catalyst of Example 2.

(Example 3)
An H-type MFI catalyst of Example 3 was obtained in the same manner as in Example 1 except that 1.29 g of NaOH and 0.67 g of NaAlO ₂ were used in the supporting step.

Example 4
An H-type MFI catalyst of Example 4 was obtained in the same manner as in Example 1 except that 1.40 g of NaOH and 0.47 g of NaAlO ₂ were used in the supporting step.

(Example 5)
An H-type MFI catalyst of Example 5 was obtained in the same manner as in Example 1 except that 1.53 g of NaOH and 0.23 g of NaAlO ₂ were used in the supporting step.

(Example 6)
An H-type MFI catalyst of Example 6 was obtained in the same manner as in Example 1 except that 1.61 g of NaOH and 0.094 g of NaAlO ₂ were used in the supporting step.

(Example 7)
An H-type BEA catalyst of Example 7 was obtained in the same manner as in Example 2 except that NH ₄ type BEA (“CP814E” manufactured by ZEOLYST, T atom: Al) was used for the crystalline metallosilicate molded body.

(Comparative Example 1)
The H-type MFI catalyst of Comparative Example 1 was used in the same manner as in Example 1, except that 1.64 g of NaOH, 0.047 g of NaAlO ₂ were used in the supporting step, and drying was performed under a nitrogen stream at 80 ° C. for 7 hours. Obtained.

(Comparative Example 2)
Comparative Example as in Comparative Example 1, except that drying under a nitrogen stream in the supporting process was performed for 0.5 hour, and the number of times of immersion in the aqueous ammonium nitrate solution and discarding of the supernatant liquid in the ion exchange process was less than in Comparative Example 1. 2 H-type MFI catalyst was obtained.

(Comparative Example 3)
Comparative Example 3 was the same as Comparative Example 2 except that drying under a nitrogen stream in the supporting process was performed for 5 hours, and the number of immersion operations in the aqueous ammonium nitrate solution and the discarding operation of the supernatant liquid was less than in Comparative Example 2. An H-type MFI catalyst was obtained.

(Comparative Example 4)
Comparative Example as in Example 1 except that 1.99 g of NaOH, 0.0094 g of NaAlO ₂ and 16.92 g of 40% by weight tetra-n-propylammonium hydroxide aqueous solution were used in the supporting step. 4 H-type MFI catalyst was obtained.

(Comparative Example 5)
70 parts by mass of NH ₄ type MFI powder (“CBV5524G” manufactured by Zeolist International Co., Ltd., T atom: Al) and 30 parts by mass of silica as binder are dispersed in ion-exchanged water, and then concentrated to a paste. did. The solid obtained by drying this concentrate at 110 ° C. was calcined at 500 ° C. for 5 hours, coarsely pulverized, and classified to 0.7 to 2.0 mm to obtain an H-type MFI catalyst of Comparative Example 5. .

(Comparative Examples 6-8)
A commercially available metallosilicate molded body molded using α-alumina as a binder was fired at 500 ° C. for 3 hours, coarsely pulverized, and then classified into 0.7 to 2.0 mm, and the H type of Comparative Examples 6 to 8 An MFI catalyst was obtained. In addition, as for the commercially available crystalline metallosilicate used, Comparative Example 6 was NH ₄ type MFI (“CBV5524GCY” manufactured by Zeolis International, T atom: Al), and Comparative Example 7 was NH ₄ type MFI (manufactured by SUD-CHEIE). “SN486 H / 99”, T atom: Al), and Comparative Example 8 is NH ₄ type MFI (“CBV3024ECY” manufactured by Zeolis International, T atom: Al). The mass ratio of (crystalline metallosilicate) / (binder) in each crystalline metallosilicate molded body used is 70/30.

The catalysts of the above Examples and Comparative Examples were analyzed with a fluorescent X-ray analyzer (“PW2404” manufactured by PHILPS, detection limit of Na ₂ O: 75 ppm), and the Na content in the catalyst converted to Na ₂ O and Si / T was calculated.

  In addition, as described below, acrolein was produced by dehydrating glycerin using the catalysts of the above Examples and Comparative Examples.

(Manufacture of acrolein)
Acrolein was synthesized by dehydrating glycerol by the following method using a reactor in which the catalysts of Examples and Comparative Examples were fixed beds.

First, a stainless steel reaction tube (inner diameter: 10 mm, length: 500 mm) filled with 15 ml of the catalyst of Example or Comparative Example was prepared as a fixed bed reactor, and this reactor was immersed in a salt bath at 360 ° C. Thereafter, nitrogen was circulated in the reactor at a flow rate of 61.5 ml / min for 30 minutes, and then a reaction gas composed of a vaporized gas of 80 mass% glycerin aqueous solution and nitrogen (reaction gas composition: glycerin 27 mol%, water 34 mol%, Nitrogen (39 mol%) was circulated at a flow rate of 632 hr ⁻¹ . The effluent gas for 30 to 60 minutes and 150 to 180 minutes after flowing the reaction gas through the reactor was cooled and liquefied and collected (hereinafter referred to as “cooled liquefied product of the collected effluent gas”). Referred to as “spill”).

  Then, qualitative and quantitative analysis of the effluent was performed by gas chromatography (GC). As a result of qualitative analysis by GC, 1-hydroxyacetone was detected together with glycerin and acrolein. Moreover, the conversion rate, the acrolein yield, and the fluctuation of the acrolein yield were calculated from the quantitative analysis results. Here, the conversion rate is a value calculated by (1− (number of moles of glycerin in the collected effluent) / (number of moles of glycerin introduced into the reactor in 30 minutes)) × 100. The yield of acrolein is a value calculated by ((molar number of acrolein) / (molar number of glycerin introduced into the reactor in 30 minutes)) × 100. The fluctuation of the acrolein yield is a value calculated by (acrolein yield of 150 to 180 minutes) / (acrolein yield of 30 to 60 minutes) × 100-100.

Table 1 shows the Si / T and Na ₂ O contents of the catalysts of Examples and Comparative Examples, and the conversion rate, acrolein yield, and yield variation of acrolein.

  As shown in Table 1, the absolute values of the acrolein yield fluctuations using the catalysts of Comparative Examples 1 and 2 with Si / T exceeding 800 are both large fluctuations exceeding 33% (Si / T is Since the acrolein yield using the catalyst of Comparative Example 3 of 1000 and the catalyst of Comparative Example 4 having Si / T of 5000 is about 2%, the glycerol dehydration catalyst suitable for the production of acrolein It ’s not something you can call.) Moreover, the absolute value of the acrolein yield fluctuation | variation using the catalyst of Comparative Examples 5-8 in which binder content exceeds 15 mass% is also a big fluctuation | variation in which all exceeded 26%. On the other hand, the absolute values of the acrolein yield fluctuations using the catalyst of the example having Si / T of 800 or less and the binder content of 15% by mass or less are all small fluctuations of 12% or less. Therefore, by using the catalyst of the example, it can be confirmed that the acrolein was produced while suppressing the yield fluctuation.

Claims (6)

  A catalyst having a crystalline metallosilicate containing Al as a T atom and used for vapor phase dehydration of glycerin, wherein Si / T in the crystalline metallosilicate is 800 or less, and the catalyst has no binder. A catalyst for dehydration of glycerin. The catalyst for dehydration of glycerol according to claim 1, wherein the crystalline metallosilicate has an H ⁺ in an extra-lattice cation.   The glycerol dehydration catalyst according to claim 1 or 2, wherein the crystalline metallosilicate has an MFI type crystal structure. Catalyst for glycerin dehydration according to any one of claims 1 to 3 content of Na in terms of Na 2 _O is less than 1.0 wt%. A method for producing acrolein by dehydrating glycerol by gas phase reaction in the presence of a catalyst, wherein the catalyst is the glycerol dehydrating catalyst according to any one of claims 1 to 4. A method for producing acrolein. A method for producing an acrolein derivative comprising a step of producing acrolein by dehydrating glycerol by gas phase reaction in the presence of a catalyst, wherein the catalyst is a catalyst for dehydrating glycerol according to any one of claims 1 to 4. A process for producing an acrolein derivative, characterized in that