CN1288000A - Method for preparing liquid alkyl diphenylamine - Google Patents

Abstract

A method for preparing liquid alkylated diphenylamine, which comprises contacting and reacting diisobutylene with diphenylamine at a temperature of 170-230°C and a pressure of 0.2-0.5MPa in the presence of an activated clay catalyst. When the product contains 4, When the content of 4'-di-tert-octyldiphenylamine was less than 20%, the reaction was stopped and the product was collected. Compared with the method disclosed in EP149,422, the method provided by the invention shortens the reaction time by 4-5 hours, and at the same time solves the disadvantage of unstable temperature fluctuation during the reaction process caused by the reflux of diisobutylene. Moreover, the appearance of the liquid alkylated diphenylamine prepared by the method of the present invention is light yellow, which is superior to dark brown similar products prepared by the method of EP149,422.

Description

Preparation method of liquid alkylated diphenylamine

The present invention relates to the preparation method of alkylated diphenylamine, in particular, is the preparation method of liquid alkylated diphenylamine as antioxidant.

Alkylated diphenylamine antioxidant not only has excellent anti-oxidation effect in oil products, but also has high thermal stability, good oil solubility and ash-free characteristics, so it has been widely used in oil products .

Alkylated diphenylamine antioxidants are generally formed by reacting olefins with diphenylamine. Due to differences in olefin structures, catalysts, and preparation processes, the structures of the obtained alkylated diphenylamines are not the same, so that the products are divided into liquids and solids. Due to the good oil solubility and easy deployment of liquid alkylated diphenylamine antioxidants, its dosage has greatly exceeded that of solid alkylated diphenylamine antioxidants.

US 3,714,257 describes a process for the preparation of alkylated diphenylamine antioxidants. In the autoclave equipment, diisobutene and diphenylamine are reacted in the presence of _AlCl3 catalyst. After the reaction, the catalyst is removed, and the unreacted diisobutene is distilled off to obtain 4,4'-dioctyldiphenylamine. The bottom is solid, with a melting point of 75-85°C. In the same way, use nonene to react with diphenylamine to obtain dinonyldiphenylamine product, which is liquid at room temperature.

US 4,704,219 discloses the method for preparing the para-position as butyl and octyl, and the ortho-position as ethyl-substituted diphenylamine antioxidant, in autoclave, add diphenylamine and aluminum trichloride, form intermediate, add ethylene and HCl gas reaction, then add diisobutene reaction. A diphenylamine product substituted by ethyl in the ortho position and butyl and octyl in the para position is obtained, and the product is liquid at room temperature.

JP2-188555 discloses the preparation method of alkylated diphenylamine using activated clay as a catalyst and using propylene trimer and diphenylamine as raw materials to obtain a light yellow liquid 4,4'-dinonyldiphenylamine product, the product Nitrogen content 3.2%.

EP 149,422 discloses that diphenylamine and diisobutene (specifically refer to 2,2,4-trimethylpentene-1) react in the presence of activated clay catalyst to prepare butyl, octyl mixed substituted diphenylamine antioxidant method, the product is liquid at room temperature. In the method, under normal pressure and a temperature not lower than 160°C, the reaction is continuously carried out by continuously dropping diisobutene until the content of 4,4'-di-tert-octyldiphenylamine in the product is less than 25%. Since the boiling point of diisobutene is 102°C, it is liquid at the reaction temperature, while diphenylamine is solid. As soon as diisobutene enters the reaction system, it is vaporized and refluxed immediately. The reaction is actually between the reflux droplets of diisobutene and the surface molecules of diphenylamine. In the process, the reactant contact is not sufficient, resulting in a long reaction time, and the product is darker in color and dark brown. On the other hand, the reaction rate of this reaction is gradually reduced along with the carrying out of reaction, and when the rate of addition of diisobutene is greater than the rate of reaction, the reflux increases, making the temperature of reaction lower than the control point; , the temperature rises sharply again, resulting in excessive temperature fluctuations, and it is difficult to achieve a stable operation process.

The purpose of the present invention is to overcome the above-mentioned defects of the prior art, and provide a method for preparing liquid alkylated diphenylamine with stable operation and relatively short reaction time.

The preparation method of liquid alkylated diphenylamine provided by the present invention is to contact and react diisobutene and diphenylamine at 170-230° C. and under the pressure to make diisobutene in a liquid state in the presence of an activated clay catalyst. When the product is When the content of 4,4'-di-tert-octyldiphenylamine is less than 20%, stop the reaction and collect the product.

Specifically, the preparation method of liquid alkylated diphenylamine provided by the present invention is to make diphenylamine under the presence of activated clay catalyst and polymerization inhibitor and nitrogen protection at 170-230°C, preferably 170-200°C. Reacts with diisobutene in liquid state. After the reaction, unreacted diisobutene was distilled off, and the catalyst waste residue was removed by filtration while hot. The performance of diisobutene distilled out is not affected and can be recycled.

The reaction pressure should make diisobutene liquid at the operating temperature, and the general operating pressure is 0.2-0.5 MPa. In order to ensure the operating pressure, a closed reactor or high-pressure reactor can be used, and the reaction equipment preferably has both reaction and distillation functions.

In the reaction raw materials, diisobutene should be in excess, for example, the molar ratio of diphenylamine to diisobutene can be 1:1.3～1:2.0. Diisobutene can be added into the reaction system at one time or several times, preferably in several times, so that the pressure at the initial stage of the reaction will not be too high.

The amount of activated clay can be changed within a wide range without causing adverse effects on the reaction. The general amount is 5-30% of the weight of diphenylamine, preferably 10-20%. Said white clay is preferably heated and dehydrated for 2 hours before use to prevent bumping during the reaction.

In the method of the present invention, a polymerization inhibitor can also be used to prevent the self-polymerization of highly active diisobutylene during the reaction, thereby improving the utilization rate of raw materials. The polymerization inhibitor may be hydroquinone or p-hydroxyanisole etc. commonly used polymerization inhibitors in this field, usually in an amount of 5-200ppm, preferably 5-100ppm. In the method of the present invention, the content of 4,4'-di-tert-octyl diphenylamine is relatively high at the initial stage of the reaction. After the reaction is carried out for 20 to 25 hours, the content of 4,4'-dioctyl diphenylamine drops below 20%. stop responding. On the contrary, if the content of 4,4'-di-tert-octyldiphenylamine in the product exceeds 20%, solids are easily precipitated in the product at normal temperature. In the light yellow liquid mixed alkyl-substituted diphenylamine product obtained by the method of the present invention, tert-butyl substituted diphenylamine accounts for 15-25%, tert-octyl-substituted diphenylamine accounts for 25-30%, tert-butyl and tert-octyl Substituted diphenylamine accounts for 25-30%, bis-tert-octyl-substituted diphenylamine accounts for 10-20%, and free diphenylamine accounts for 2-4%.

The liquid amine antioxidant prepared by the method of the present invention is compounded with antioxidants of different structures, such as dialkyl dithiocarbamate. (zinc), zinc dialkyldithiophosphate, 4,4'-methylenebis(2,6-di-tert-butylphenol) have better effect. It has good compatibility with monosuccinimide ashless dispersant, overbased calcium (magnesium) sulfonate detergent, metal deactivator, etc.

The preparation method of liquid alkylated diphenylamine provided by the present invention, by controlling the reaction pressure, diisobutene is reacted with diphenylamine in liquid state, the contact probability of diisobutylene and diphenylamine molecule is increased, and the method disclosed in EP 149,422 Compared with the method, the reaction time is shortened by 4 to 5 hours, and at the same time, the disadvantage of unstable temperature fluctuation in the reaction process caused by the reflux of diisobutylene is solved. Moreover, the appearance of the light yellow liquid alkylated diphenylamine antioxidant prepared by the method of the present invention is better than that of dark brown similar products prepared by the method of EP149,422.

Below by example the present invention will be further described. In the example, 4,4'-di-tert-octyl diphenylamine content is determined by gas chromatography.

Example 1

In the autoclave of 250ml, add the diphenylamine of 64.4 grams, 85.0 grams of diisobutylene (Shijiazhuang oil refinery product, 2,2,4-trimethylpentene-1 content 80%, 2,2,4-trimethylpentene Pentene-2 content 15%, the balance is mixed hydrocarbon components.), 13 grams of activated clay (Jinzhou Yixian Petroleum Clay Co., Ltd. product), 20ppm hydroquinone polymerization inhibitor, three reaction systems with nitrogen replacement, 100 Stirring was started at °C, the temperature was raised to 175 °C, and the reaction pressure was 0.52 MPa. As the reaction progressed, the pressure gradually decreased to 0.3MPa. After the reaction was carried out for 24 hours, sampling analysis determined that the content of 4,4'-di-tert-octyldiphenylamine in the product was 17.8%. Cool the material and transfer it to a 250ml there-necked flask, distill under reduced pressure to remove unreacted diisobutylene and a small amount of water, then reduce the temperature of the material to below 140°C, filter and remove the catalyst waste residue, and obtain 110 grams of light yellow liquid product. Nitrogen content 4.36%.

Example 2

Add 64.4 grams of diphenylamine, 34 grams of diisobutylene, 13 grams of activated clay catalyst, 20 ppm p-hydroxyanisole polymerization inhibitor in a 250 ml stainless steel autoclave, and replace the reaction system with nitrogen three times. Start stirring at 100°C, heat up to 180°C, and the reaction pressure is 0.3MPa. As the reaction progresses, the pressure gradually decreases to 0.18MPa. After the reaction was carried out for 4 hours, 12.8 grams of diisobutene was added by a metering pump, and the temperature was kept to continue the reaction. After the reaction was carried out to 16 hours, 21.2 grams of diisobutene was added, and the temperature was kept to continue the reaction. Isobutene continued to react for 24 hours, and the content of 4,4'-di-tert-octyldiphenylamine in the product was found to be 15.6% by sampling analysis. After the reaction, the product was collected according to the method of Example 1 to obtain 108 grams of light yellow liquid product with a nitrogen content of 4.45%.

Example 3

In a 250ml stainless steel autoclave, add 64.4 grams of diphenylamine, 46.8 grams of diisobutylene, 9.6 grams of active earth catalyst, 50 ppm hydroquinone polymerization inhibitor, and replace the reaction system with nitrogen three times. The temperature was raised to 175°C to start the reaction, and the pressure in the reactor was 0.21MPa. After 10 hours of reaction, 17.0 grams of diisobutene was added by a metering pump, and the temperature was maintained. After continuing the reaction for 18 hours, 8.5 grams of diisobutene was added for the second time, and the reaction was completed after 22 hours. Sampling and analysis showed that 4,4' - Di-tert-octyldiphenylamine content of 17.2%. The product was collected according to the method of Example 1 to obtain 107 g of light yellow liquid product with a nitrogen content of 4.62%.

Example 4

In a 250ml stainless steel autoclave, add 64.4 grams of diphenylamine, 34 grams of diisobutylene, 12.5 grams of activated clay catalyst, 50 ppm hydroquinone polymerization inhibitor, and replace the reaction system with nitrogen three times. Stirring was started at 100°C, the temperature was raised to 180°C to start the reaction, and the pressure in the kettle was 0.22MPa. After the reaction was carried out for 2 hours, 12.8 grams of diisobutene was added through a metering pump, and the temperature was maintained to continue the reaction. After 16 hours, 17.8 grams of diisobutene was added, and after the reaction was carried out for 20 hours, 13.2 grams of diisobutene was added, and the reaction was continued for 22 hours At the end, sampling and analysis showed that the content of 4,4'-di-tert-octyldiphenylamine in the product was 13.8%. The product was collected according to the method of Example 1 to obtain 108 grams of light yellow liquid product with a nitrogen content of 4.53%.

Example 5

In a 250ml stainless steel autoclave, add 64.4 grams of diphenylamine, 46.8 grams of diisobutylene, 9.6 grams of activated clay, 60 ppm hydroquinone polymerization inhibitor, and replace the reaction system with nitrogen three times. Stirring was started at 100°C, and the temperature was raised to 180°C to start the reaction. After reacting for 10 hours, add 17.4 grams of diisobutylene by a metering pump, keep the reaction temperature to continue the reaction, when the reaction is carried out to 18 hours, then add 13.5 grams of diisobutylene, react to 22 hours and finish, sampling analysis records 4, The content of 4'-di-tert-octyldiphenylamine is 18.0%. The product was collected according to the method of Example 1 to obtain 109 g of light yellow liquid product with a nitrogen content of 4.68%.

Example 6

The ASTMD-2272 rotating oxygen bomb method is used to carry out the oxidation test on the example product to measure the oxidation induction period of the oil product. The longer the induction period, the better the anti-oxidation performance. The base oil was 150SN neutral oil from Dalian Petrochemical Company, and 0.5% of the product of Example 3 was added, and compared with several similar foreign products, the test results are shown in Table 1.

Table 1 additive dose,% Oxidation induction period, minutes Example 3 0.5 104 L-57 0.5 100 V-81 0.5 77 LZ5150A 0.5 64 Base oil 150SN - 34

Claims (8)

1. The preparation method of liquid alkylated diphenylamine is characterized in that, in the presence of activated clay catalyst, diisobutene and diphenylamine are contacted and reacted at 170-230° C. and under the pressure that makes diisobutene in a liquid state. When the product contains 4 , When the content of 4'-di-tert-octyldiphenylamine is less than 20%, stop the reaction and collect the product. 2. According to the said preparation method of claim 1, it is characterized in that, the reaction temperature is 170～200 ℃. 3. According to the said preparation method of claim 1, it is characterized in that, the reaction pressure is 0.2～0.5MPa. 4. According to the said preparation method of claim 1, it is characterized in that the molar ratio of diphenylamine to diisobutylene is 1: 1.3～2.0. 5. According to the said preparation method of claim 1, it is characterized in that diisobutylene can be added once or several times into the reaction system. 6. According to the said preparation method of claim 1, it is characterized in that, the active clay consumption is 5～30% of diphenylamine weight. 7. According to the said preparation method of claim 1, it is characterized in that, the polymerization inhibitor can also be added in the reactant, and the consumption is 5～200ppm. 8. According to the said preparation method of claim 7, it is characterized in that said polymerization inhibitor is selected from hydroquinone or p-hydroxyanisole.