JP2621263B2 - Process for producing alkenyl succinic anhydride - Google Patents

Description

The present invention relates to a method for producing alkenyl succinic anhydride. Specifically, the present invention provides a alkenyl succinic anhydride having a good hue by suppressing the formation of tar-like by-products by performing the reaction under specific conditions when the olefin is subjected to a thermal addition reaction with maleic anhydride. It relates to a method of manufacturing.

[Conventional technology]

Alkenyl succinic anhydrides are widely used in lubricating oil additives, epoxy resin hardeners, resin modifiers, plasticizers, dispersants, rust inhibitors, and the like, and are recently attracting attention.

Generally, alkenyl succinic anhydride is produced by a heat addition reaction of an olefin and maleic anhydride under heating at 180 to 250 ° C. At this time, by-products such as tar-like substances and high-molecular weight coalescence are produced. In addition, significant coloration occurs, deteriorating the quality of the product and limiting the use of the product.

[Problems to be solved by the invention]

Various methods have been proposed for suppressing the generation of the by-products described above. For example, a method of adding a hydroxy aromatic compound or an amino aromatic compound (US Pat. No. 3,412,11)
No. 1), a method of adding a sterically hindered phenol compound (US Pat. No. 3,476,774), a method of adding a phosphite (Japanese Patent Publication No. 50-33720), a method of adding a phosphorus-containing organic metal ion sequestering agent or orthophosphoric acid. Method of adding (JP 49
-26221), a method of adding an organic chlorine compound (Sho No. 5)
2-23668), a method of adding a halogen or a halogen compound (Japanese Patent Publication No. 52-39674), and a method of adding an organic phosphite (Japanese Patent Application Laid-Open No. 56-12382).

Although these methods have an effect of suppressing the formation of the by-products, the effect is not necessarily sufficient.
In particular, when the reaction temperature is 200 ° C. or higher, the effect of suppressing the generation of by-products is reduced in the method of adding an organic chlorine compound or a halogen compound, and the use of the halogen compound causes corrosion of the apparatus. It is highly toxic and is not preferable in terms of work management. In addition, phosphoric acid, phosphoric acid ester or phosphite is corrosive to the same degree as strong acid under high temperature conditions such as reaction between olefin and maleic anhydride, so it is necessary to use equipment made of special materials. I do.

[Means for solving the problem]

In view of this situation in the prior art, the present inventors have conducted intensive studies to suppress the formation of by-products such as tar-like substances during the thermal addition reaction between olefin and maleic anhydride. And in the presence of a specific polymer and under a specific reaction condition, a heat addition reaction can be performed to suppress the formation of the above-mentioned tar-like by-product, and the problem of the hue and quality of the product is improved. This has led to the present invention.

That is, the gist of the present invention is to provide a method for producing an alkenyl succinic anhydride by a thermal addition reaction between an olefin and maleic anhydride, wherein the olefin and the general formula (I) are previously added to the reaction system. Wherein R represents a hydrogen atom or an alkyl group having 4 to 58 carbon atoms, and n represents an integer of 2 to 30. The concentration of the polymer represented by the following formula in the reaction mixture is 5 to 5. Then, maleic anhydride was added to the reaction system so that the concentration of maleic anhydride in the reaction solution was 30% based on the total number of moles of the charged olefin and maleic anhydride.
Mol% or less, and the final amount of maleic anhydride charged was 1: 0.8 to 1: 2 in terms of the molar ratio of olefin to maleic anhydride, and the conversion of maleic anhydride was reduced. Perform the reaction at a reaction temperature of 170-210 ° C until at least 30%, then raise the reaction temperature to at least 5 ° C.
And producing the alkenyl succinic anhydride.

 Next, the present invention will be described in detail.

The starting olefin in the method of the present invention is a compound having an ethylenically unsaturated double bond, and usually has 2 to 500, preferably 4 to 300, more preferably 8 to 100 carbon atoms. The olefin may be a single product or a mixture of those having different numbers of carbon atoms.
For example, a mixture of α-olefins having 12 and 14 carbon atoms (for example, “Dialen 124” (registered trademark) manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) and a mixture of α-olefins having 16 and 18 carbon atoms (also “Dialen 168”) ), Α-olefin mixtures having 20 to 28 carbon atoms (also “Dialen 208”), α-olefin mixtures having 30 to 60 carbon atoms (also “Dialen 30”) and the like are preferably used.

In the present invention, when the above-mentioned olefin and maleic anhydride are subjected to a thermal addition reaction, the reaction system is represented by the following general formula (I): (Wherein, R represents a hydrogen atom or an alkyl group having 4 to 58 carbon atoms, and n represents an integer of 2 to 30).

Preferred as the polymer represented by the general formula (I) are those wherein R in the general formula (I) is an alkyl group having 28 to 50 carbon atoms and n is 3 to 20, more preferably It is in the range of 5 to 15.

As the polymer represented by the general formula (I), generally, an α-olefin having 6 to 60 carbon atoms and maleic anhydride are used as radical polymerization initiators such as di-t-butyl peroxide and t-butyl hydroperoxide. What was obtained by copolymerizing in the presence of the radical generator is used.

The amount of the polymer represented by the general formula (I) is in the range of 5 to 30% by weight, preferably 10 to 20% by weight in the reaction mixture. If the used amount is less than the above lower limit, the effect of suppressing the formation of by-products such as the tar-like substance gradually decreases as the used amount is reduced. In addition, when the amount of use exceeds the above upper limit, even if the amount of use is increased, the effect of suppressing the generation of the by-products is not particularly changed, and conversely, the cost is increased and the quality of the product is deteriorated. It is not preferable because it occurs.

The polymer represented by the above general formula (I) is usually used by being previously mixed with one of an olefin and maleic anhydride and then added to the reaction system.

In the method of the present invention, when a predetermined amount of the polymer represented by the general formula (I) is present in the reaction system to cause a thermal addition reaction between the olefin and maleic anhydride, the concentration of the maleic anhydride in the reaction solution is determined. 30 mol% or less based on the total number of moles of the charged olefin and maleic anhydride, preferably
25 mol% or less, more preferably in the range of 2 to 25 mol%, and the conversion of maleic anhydride is at least 30 mol%.
%, Preferably 40-80%, more preferably 50-75%, the reaction temperature is 170-210 ° C, preferably 170-200 ° C.
C., more preferably 170-190.degree. C., to carry out the first-stage reaction.

In the first-stage reaction, when the concentration of maleic anhydride in the reaction system is higher than the upper limit, the generation of by-products such as the tar-like substance is significantly increased, and the reaction rate of maleic anhydride is When the reaction proceeds to the second stage reaction below the lower limit of the above, in the second stage reaction, by-products such as the tar-like substances increase, and the reaction temperature in the first stage reaction is higher than the above upper limit value. This is not preferable because by-products such as the above-mentioned tar-like substances are significantly increased.

As a method of the first-stage reaction, a predetermined amount of an olefin is charged to a reactor in advance, and maleic anhydride is continuously or intermittently mixed at a predetermined temperature such that the maleic anhydride concentration in the reaction solution is in the above range. And a reaction method is adopted. The charged molar ratio of olefin to maleic anhydride in the above reaction is 1: 0.8 to 1: 2, more preferably 1: 1.
The range is from 1 to 1: 2. The reaction is usually performed without a solvent. Further, the reaction is usually preferably carried out under atmospheric pressure, but can be carried out under increased or reduced pressure.

The first-stage reaction solution is then subjected to the second-stage reaction, and the reaction temperature is higher than the reaction temperature of the first-stage reaction by 5 ° C or more, preferably 5 to 60 ° C, more preferably By performing the reaction at a temperature higher by 10 to 40 ° C,
The conversion of maleic anhydride can be increased to 80 to 100%.

Unreacted maleic anhydride and olefin can be removed by heating under reduced pressure, if necessary.

The alkenyl succinic anhydride thus obtained is free of tar-like by-products, has a good hue, has a melting point usually in the range of -50 to 95 ° C, and has a viscosity at 100 ° C of usually 10 to 1000 cp. It is. In particular, when an α-olefin having 28 or more carbon atoms is used, the melting point is 55 ° C to 95 ° C,
The viscosity at 100 ° C. is 30 to 150 cp, and is advantageously used as a resin modifier, a dispersant, a rust preventive, and the like.

〔Example〕

Next, embodiments of the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples as long as the gist is not exceeded.

In addition, the measuring method of each physical property in the following Examples is as follows.

Melting point: Measured using an automatic melting point measuring apparatus (Mettler FP).

Penetration: Measured at 25 ° C. according to ASTM-D-1321-6 / T.

Saponification value: Measured according to JIS K0070.

Molecular weight: measured by GPC under the following conditions.

Apparatus-GPC-8000 column, manufactured by Toyo Soda Kogyo Co., Ltd.-TSK gel G (100 + 2000 + 3000 + 4000) HXL, 7.8
mmφ × 300 mm Eluent-THF 1 ml / min Calibration curve-polystyrene standard sample Example-1 580 g of an α-olefin mixture having 30 to 60 carbon atoms (“Dialen 30” (registered trademark) manufactured by Mitsubishi Chemical Industry Co., Ltd.) 0.87
Mol) and an α-olefin / maleic anhydride copolymer (in the general formula (I), R is an alkyl group having 28 to 58 carbon atoms and n is an integer of 5 to 10).
99.6 g (maleic anhydride copolymer) of 99.6 g (15% based on the total weight of the charged α-olefin and maleic anhydride) was charged into a Pyrex glass reactor, heated to 100 ° C., and sufficiently replaced with nitrogen gas. Thereafter, 85 g (0.87 mol) of maleic anhydride was continuously dropped at a constant rate over a period of 5 hours and 50 minutes at a temperature of 180 ° C. The concentration of residual maleic anhydride in the reaction solution immediately after the completion of the dropwise addition of maleic anhydride was 16.9 mol% with respect to the total number of moles of the charged olefin and maleic anhydride, and the conversion of maleic anhydride was 66.2%. .

Next, the reaction solution was further reacted at a temperature of 210 ° C. for 4 hours and 30 minutes. The resulting reaction solution had a maleic anhydride reaction rate of 94.5%.

Thereafter, unreacted substances were removed from the reaction solution at a pressure of 5 mmHg and a temperature of 162 ° C.

The obtained reaction solution had no tar-like by-product and had a good hue. The physical properties are shown below.

Melting point: 73.5 ° C Saponification number: 103 Molecular weight: 2740 Penetration: 5.5 Comparative example-1 α-olefin mixture having 30 to 60 carbon atoms (“Dialen
30 ") 544 g (0.812 mol) and maleic anhydride 79.6 g (0.8
12 mol) into a Pyrex glass reactor,
C. and the atmosphere was sufficiently replaced with nitrogen gas. Then, this was heated to a temperature of 210 ° C. and reacted for 7.0 hours. As a result, the conversion of maleic anhydride was 96.0%.

Thereafter, unreacted substances were removed from the reaction solution at a pressure of 7 mmHg and a temperature of 160 ° C.

In the obtained reaction solution, the tar-like by-product settled at the bottom and formed a layer. The product after removing the tar-like by-product was as follows.

Melting point: 73.5 ° C Saponification value: 114 Molecular weight: 2550 Penetration: 4.5 Comparative example-2 α-olefin mixture having 30 to 60 carbon atoms (“Dialen
30 ") 464 g (0.693 mol) and 79.8 g of the same α-olefin / maleic anhydride copolymer used in Example-1
(15% based on the total weight of the charged α-olefin and maleic anhydride) and 67.9 g (0.693 mol) of maleic anhydride were charged into a Pyrex glass reactor, heated to 100 ° C, and sufficiently replaced with nitrogen gas. Then, this was heated to 210 ° C. and reacted for 7.0 hours. As a result, the conversion of maleic anhydride was 91.1%.

Thereafter, unreacted substances were removed from the reaction solution at a pressure of 7 mmHg and a temperature of 160 ° C.

In the obtained reaction solution, the formation of tar-like by-products was very small.

Melting point: 74.5 ° C Saponification number: 116 Molecular weight: 2110 Penetration: 6.0 Comparative example-3 α-olefin mixture having 30 to 60 carbon atoms (“Dialen
696 g (1.04 mol) of 30 ″) was charged into a Pyrex glass reactor, heated to 100 ° C., and sufficiently purged with nitrogen gas.
Then, at a temperature of 180 ° C, 102 g of maleic anhydride was added.
(1.04 mol) was continuously dropped at a constant rate over 2.9 hours. The concentration of residual maleic anhydride in the reaction solution immediately after the completion of the dropping of maleic anhydride was 21.9 mol% based on the total number of moles of the charged olefin and maleic anhydride, and the reaction rate of maleic anhydride was 56.2 g. .

Next, the reaction solution was aged at a temperature of 210 ° C. for 4.0 hours. The resulting reaction solution had a maleic anhydride reaction rate of 89.0%.

In the obtained reaction solution, the formation of tar-like by-products was very small.

Melting point: 75 ° C. Saponification value: 121 Molecular weight: 2370 [Effect of the Invention] By the method of the present invention, the formation of by-products during the production of alkenyl succinic anhydride by heat addition reaction between olefin and maleic anhydride is suppressed. And the hue and quality of the product are improved.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-56-115758 (JP, A) JP-A-54-76516 (JP, A) JP-A-55-100374 (JP, A)

Claims (1)

(57) [Claims] 1. A process for producing an alkenyl succinic anhydride by subjecting an olefin and maleic anhydride to a thermal addition reaction, wherein the olefin and the general formula (I) are previously added to the reaction system. Wherein R represents a hydrogen atom or an alkyl group having 4 to 58 carbon atoms, and n represents an integer of 2 to 30. The concentration of the polymer represented by the following formula in the reaction mixture is 5 to 5. Then, maleic anhydride was added to the reaction system so that the concentration of maleic anhydride in the reaction solution was 30% based on the total number of moles of the charged olefin and maleic anhydride.
Mol% or less, and the final amount of maleic anhydride charged was 1: 0.8 to 1: 2 in terms of the molar ratio of olefin to maleic anhydride, and the conversion of maleic anhydride was reduced. Perform the reaction at a reaction temperature of 170-210 ° C until at least 30%, then raise the reaction temperature to at least 5 ° C.
A process for producing an alkenyl succinic anhydride, wherein the reaction is carried out at an elevated temperature.