JPH031294B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for ortho-alkylating phenols. In particular, the present invention relates to a process for reacting a phenol unsubstituted in at least one ortho position with an alkanol in the presence of a catalyst. It is well known to react unsubstituted phenols in at least one ortho position with alkanols in the presence of catalysts. Such reactions include, for example, orthocresol (useful for the production of herbicides, for example), 2,6-xylenol (useful for the production of polyphenylene ethers, for example), 2,3,6-
It is used to produce trimethylphenol (useful for example in the production of vitamin E), etc. Also, many catalysts for the ortho-alkylation of phenols are known. For example, British patent no.
No. 602257 uses alumina as a catalyst,
It discloses that the reaction is carried out at 345°C. however,
In this reaction, a considerable amount of phenol remains unreacted and significant amounts of m- and p-alkylated products are produced as by-products. U.S. Pat. No. 3,843,606 also discloses the use of magnesia as a catalyst and reports that phenolic feedstocks are converted with fairly high conversion and selectivity. However, the reaction temperature in this case exceeds 400°C, and requires a high temperature of about 460°C, for example. It is also known to use iron oxide as a component of the catalyst in the ortho-alkylation of phenols. For example, U.S. Pat. No. 3,716,589 discloses a catalyst containing oxides of iron and other metals (M) in amounts sufficient to form a spinel having the formula MFe ₂ O ₄ . By carrying out the alkylation reaction at approximately 350°C using this catalyst, alkylation at the ortho position is achieved with high selectivity, but the conversion rate does not exceed 71% and a large amount of phenolic raw material must be recycled. Must be. Other known documents disclosing ortho alkylation catalysts include British Patent No. 1378179. This discloses catalysts containing oxides of iron, vanadium and other metals. British Patent No. 1428057 also discloses a catalyst containing oxides of iron and silicon. CA, 77:101173d discloses catalysts containing significant amounts of vanadium and iron oxides as well as other metal oxides. CA, 78:3944g discloses a catalyst containing a mixture of indium and iron oxides. Further, CA, 79:78384d discloses a catalyst containing a spinel represented by MFe ₂ O ₄ (where M is barium, calcium, magnesium or a transition metal). CA, 81:105003d discloses a catalyst containing iron oxide and nickel oxide such that the molar ratio of nickel to iron is 1:2. CA, 82: 155769z
discloses a catalyst containing manganese oxide and iron oxide, and optionally further containing cobalt oxide. CA, 84:58898z discloses a catalyst of Zn ₂ Fe ₂ Mo ₀ . ₀₃ O ₄ . CA, 90:
6086n has the formula MFe ₂ O ₄ (where M is Mg, Ca, Ba,
(Cu, Ni, Cr, Co or Cu-Zn) catalysts are disclosed. CA, 93:71286d.
A catalyst consisting of a mixture of oxides of Fe, Cr, Sb, V and Si is disclosed. CA, 94:103010y is iron, Mo, Sn, W and
It discloses a catalyst containing one type of oxide selected from Zr, and in some examples thereof, there is a catalyst containing iron and zirconium in an atomic ratio of 96:4. European Patent Publication No. 19476 (1980
(published on November 26, 2013) contains a large amount of iron oxide and a small amount of Ga.
A catalyst containing an oxide of a metal selected from Ge, Y, Nd, Hf, Bi and Ta is disclosed.
Examples 45, 46, 49 and 50 disclose catalysts of iron, germanium and their oxides containing Zr or Sn in an atomic ratio of 97:1.8:1.2. As is clear from the above, mixtures of various metal compounds have been proposed as catalysts for the ortho-alkylation reaction of phenols, but it is difficult to estimate the most suitable catalyst. According to the invention, the process for preparing o-alkylphenols comprises at least one ortho-unsubstituted monovalent phenol containing at least 92% w/w oxide of iron (calculated as Fe ₂ O _{3 )} . ) and Cd,
In the presence of a catalyst containing 0.5-3% w/w of oxides of other metals selected from Ce, Co, Ni, Ti and Zr.
It involves reacting with C _1-4 alkanol at 300-500℃. The catalyst used in the present invention contains iron oxide as a main component. Such tentacles are suitably made from Fe ₂ O ₃ , although any other form of iron oxide may be used. When using Fe ₂ O ₃
It may be changed to Fe ₃ O ₄ . The oxides of metals other than iron in the catalyst of the present invention include Group 3 (Cd) of the periodic table;
Catalysts which optionally contain oxides of such metals, which may be of group (Ce), group (Ti or Zr) or group (Co or Ni), may be used during their manufacture or use. may be prepared from salts or other compounds that may be converted into The amount of metals other than iron in the catalyst is 0.5 to 3% w/w when calculated as their oxides. The most preferred amount is usually about 1% by weight. In this specification, percentages of components in the catalyst are obtained based on the dry weight of the component relative to the total weight of the catalyst. The catalyst of the present invention may contain oxides of metals other than iron that do not adversely affect the reaction, and the amount thereof is usually 5% by weight or less. It is often preferred that the catalyst contains less than 5% by weight of Cr ₂ O ₃ . It may also be preferred that the catalyst comprises an oxide or salt of an alkali metal, such as an oxide or salt of Na or K. A suitable example of such a compound is potassium carbonate. The amount of such alkali metal compounds is 3% by weight or less. The catalyst may be prepared in a manner customary per se. It may be prepared in any form suitable for use in gas phase reactions. The phenol used as a raw material may be one in which at least one ortho position is unsubstituted. Examples include phenol and m-cresol. The alkanol is an alkanol having 1 to 4 carbon atoms, and particularly preferably methanol or ethanol. According to the process of the invention, phenol is reacted with methanol to give o-cresol and/or 2,6-xylenol, and m-cresol is reacted with methanol to give 2,3,6-trimethylphenol. Alkanols are usually used in excess. Alkanol/phenol feeds usually contain water, which can extend catalyst life. Reaction temperature is 300-500℃, preferably 320-420℃
temperature, often 330-360°C. The reaction may be carried out using either fluidized bed or fixed bed equipment. Although the pressure is not particularly limited, it is often appropriate to carry out the reaction at atmospheric pressure or slightly higher pressure. The process of the invention is typically carried out at a space velocity of, for example, 0.3 to 3 liters of liquid feedstock per liter of catalyst per hour. However, this rate is often reduced when dialkylation is required.
It is less than 1.0, and if monoalkylation is desired, it will be a high value. The present invention will be explained in more detail by giving specific examples below. In these examples, all parts and percentages are by weight unless otherwise indicated. Note that catalyst D is for comparison. Preparation of Catalyst Compositions A to K 600 parts of iron nitrate (Fe(NO ₃ ) _{3.9H 2} O) and 3.82 parts of chromium nitrate (Cr(NO ₃ ) _{3.9H 2} O) were dissolved in 6000 parts of water. Zirconium nitrate (Zr
Add 4.21 parts of (NO ₃ ) _{4.5H 2} O) in the form of a 10% aqueous solution. A dilute ammonia aqueous solution was added to this while stirring to make it neutral. After stirring for a while, the generated hydrogel was collected by filtration and washed.
Dry at 180°C for 10 hours. Add this to potassium carbonate
Soak overnight in a solution containing 0.048 parts, re-dry and calcined in air at 470°C for 4.5 hours to form pellets of 3.1 mm (Catalyst A). Catalysts B, C and D were prepared in the same manner as above except that the amount of zirconium nitrate was varied. Catalysts E, F, G, H and I were also prepared in the same manner using a solution of titanium tetrachloride, lead nitrate, cadmium nitrate, tin chloride or cerium nitrate in place of zirconium nitrate. Catalysts J and K were also prepared in a similar manner using nickel nitrate or cobalt nitrate. The catalysts A to I thus prepared have the following compositions (on a dry weight basis; the balance of each composition is Fe ₂ O ₃ ):

【table】

[Table] Fill a mild steel reaction tube with 60ml of each of the above catalysts,
It was maintained at ℃. A gaseous mixture of methanol, phenol and water (molar ratio 5:1:1) was mixed at a space velocity (LHSV) of 0.4-0.6Kg liquid feedstock/liter catalyst/
It was passed through the catalyst bed for an hour. The results were as shown in the table below.

TABLE Other catalysts used in the present invention may be prepared similarly to Catalysts AI. For example, Hg,
In, lanthanum series elements and Sc may be introduced in the form of their nitrates, and As may be introduced in the form of their chlorides. Various catalysts can be prepared in this way, with or without Cr ₂ O ₃ and/or alkali metals, representative examples of which are: Fe ₂ O ₃ + 1% CdO + 1.1 %Cr ₂ O ₃ +0.05%K ₂ CO ₃ Fe ₂ O ₃ +1%CeO Fe ₂ O ₃ +1%Co ₂ O ₃ +1%Cr ₂ O ₃ Fe ₂ O ₃ +1%PbO +0.04%K ₂ CO ₃

Claims (1)

Claims: 1. The presence of a catalyst comprising at least 92% w/w (calculated as Fe ₂ O ₃ ) of an oxide of iron with a monovalent phenol unsubstituted in at least one ortho position. A method for producing an o-alkylphenol comprising reacting it with a C _1-4 alkanol at 300-5000°C, wherein the catalyst is Cd, Ce, Co, Ni,
Oxides of other metals selected from Ti and Zr0.5−
3% w/w. 2. The method according to item 1, wherein the other metal is a group metal selected from Co and Ni. 3. The method according to claim 1, wherein the other metal is a group metal selected from Ti and Zr. 4. The method according to item 1, wherein the other metal is Ti. 5. The method according to any one of paragraphs 1-4, wherein the alkanol is methanol. 6 the phenol is phenol itself and the product is o-cresol and/or 2,
6. The method of claim 5, comprising 6-xylenol. 7 Phenol with at least 92% iron oxide w/
A process for the production of o-cresol and/or 2,6-xylenol comprising reacting with methanol at 300-500°C in the presence of a catalyst containing w (calculated as Fe ₂ O ₃ ), said catalyst comprising TiO ₂ 0.5
-1 and 4 characterized by also containing 3% w/w
- The method according to any of paragraph 6. 8. A method according to any of paragraphs 1-7, wherein the catalyst further comprises _Cr2O3 in an _amount of 5% w/w or less. 9. A method according to any of paragraphs 1-8, wherein the catalyst further comprises an alkali metal, oxide or salt in an amount of 3% w/w or more. 10. The method according to any of paragraphs 1-9, carried out at 320-420°C. 11. The method according to any one of paragraphs 1-10, which is carried out in the presence of water.