JPS6340781B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a process for producing oil-soluble sulfonic acids or sulfonate salts from improved alkyl aromatic compounds known as alkylates, and more particularly as lubricant additives. The present invention relates to a method for producing overbased sulfonates, particularly overbased calcium sulfonates, which reduces the tendency to froth when used.

Sulfonates, especially overbased sulfonates of calcium, barium, or magnesium, are widely used as lubricating oil additives. The term overbased is used to describe sulfonate salts that contain an excess amount of metal over the amount required to react with the sulfonic acid to yield the sulfonate salt. Often the excess metal is in its carbonate form, in which case the overbased sulfonate consists of a colloidal dispersion of the metal carbonate in the metal sulfonate as a dispersant.
This overbased sulfonate is used as a dispersant in lubricating oils, and its high basicity neutralizes acids that form in the crankcase during engine operation, thus reducing corrosion.

Sulfonic acids and sulfonate salts are generally obtained from aromatic monoalkylates with branched or straight alkyl chains. Oil-soluble sulfonic acids are obtained from alkylates containing alkyl groups of 16 or more, generally 20 or more carbon atoms, which alkyl groups are usually branched. This is because branched chain olefins are more readily available and are less expensive than corresponding straight chain olefins.

However, one problem associated with the use of overbased sulfonates, especially overbased sulfonates derived from branched chain alkylates, is that despite the inclusion of antifoam agents in the oil, after a short period of use, , which tends to cause undesirable lubricant foaming during engine operation. This problem is particularly acute with overbased calcium sulfonates. It is proposed in British Patent Specification No. 1390951 to overcome the above problem by preparing sulfonic acids from a mixture of straight-chain and branched-chain alkylates.
Although this technology has been successful, it requires significant amounts of linear alkylate, which increases cost. This is because the straight chain olefins from which these alkylates are made are more expensive than the branched chain olefins we use. When alkylating aromatic compounds with mixtures of branched and straight-chain olefins, thereby obtaining alkylates for producing sulfonic acids, it has been found that the same effect can be achieved with considerably less straight-chain olefins. Served.

Therefore, the present invention provides a mixture comprising up to 95% by weight of a branched chain olefin containing 15 to 40 carbon atoms and at least 5% by weight of a straight chain olefin containing 16 to 30 carbon atoms, which A method for producing a sulfonic acid or sulfonate salt of an alkylate is provided, comprising alkylating an aromatic compound and then sulfonating the alkylate in a molar ratio of 10:1 to 1:1 of the olefin mixture described above.

This alkylation reaction can be accomplished by any known alkylation method. A preferred method is to use a Friedel-Crafts catalyst such as aluminum trichloride, preferably with hydrochloric acid. No special conditions are required for alkylation. What is important in the present invention is the composition of the olefin feed and the ratio of the substances used. In one aspect of the invention relating to alkylates for the production of overbased sulfonate salts,
This method is particularly useful when the aromatic compound is benzene. This is because the foaming problem of lubricants containing overbased alkylbenzene sulfonates is particularly acute.

The olefin mixture used as feed must contain at least 5% by weight of linear olefins.
It has been found that olefin mixtures containing less than 5% by weight of linear olefins do not provide improved sulfonic acids and sulfonate salts. The inventors have also found that there is no further improvement in effectiveness when the mixture contains more than 30% by weight of linear olefin. Thus, since straight chain olefins are more expensive than branched chain olefins, the mixture preferably contains 5 to 30% by weight of straight chain olefins, although this is not a requirement. The inventors have found that when the linear olefin from which the sulfonate is derived contains 16 or fewer carbon atoms, there is little reduction in the tendency of the lubricant to foam. It is also preferred to use olefins containing 24 or fewer carbon atoms, as higher olefins tend to be waxy and unsuitable.

In order to establish the desired oil solubility and viscosity of the sulfonate obtained from the alkylate, the branched chain olefin must contain 15 to 40 carbon atoms. Because of its ready availability, the inventors choose to use oligomers of propylene as the branched chain olefin.

The ratio of aromatics to olefin mixture in the reaction of this invention should be between 10:1 and 1:1 by volume to avoid using excess olefin. This ensures that the product is essentially monoalkyl aromatic, which has proven to be important. This is because dialkyl aromatics containing branched chain alkyl groups are difficult to sulfonate.

The alkylates obtained can themselves be used, for example, as synthetic lubricants. However, the main applications to which this invention relates are alkylaryl sulfonic acids, particularly sulfonic acids which can later be converted into overbased sulfonates, especially calcium sulfonates, or into neutral sulfonates, such as sodium sulfonate, which are used as emulsifiers. As a raw material in manufacturing.

Therefore, the present invention provides a mixture comprising up to 95% by weight of a branched chain olefin containing 15 to 40 carbon atoms and at least 5% by weight of a straight chain olefin containing 16 to 30 carbon atoms, which A method for producing a sulfonic acid or sulfonic acid salt of an alkylate, which comprises sulfonating an alkylate obtained by alkylating an aromatic compound in a molar ratio of 10:1 to 1:1 of the above olefin mixture. provide.

Any known sulfonation method can be used. For example, the alkylate can be sulfonated with concentrated sulfuric acid, oleum, or sulfur trioxide in sulfur dioxide, the latter method being preferred. After sulfonation,
Purify the sulfonic acid by standard methods or add olefin and optionally water as described in my Belgian Patent No. 851,516 and as described in my British Patent No. 1,469,203. Purification aids such as the addition of ether-containing compounds can be included.

The sulfonic acids produced by the present invention can be neutralized to form sulfonic acid salts that can be used as detergents, dispersants, and emulsifiers. The choice of cation will depend on the intended use of the sulfonate. When used as emulsifiers or in oil recovery, the cations are generally alkali metal or quaternary nitrogen cations, whereas when used as lubricant additives, the cations are usually calcium, barium, or magnesium; Acid acids are often overbased.

Therefore, the present invention provides an aromatic compound with 1 mole of a mixture comprising up to 95% by weight of a branched chain olefin containing 15 to 40 carbon atoms and at least 5% by weight of a straight chain olefin containing 16 to 30 carbon atoms. An anion is derived from the sulfonic acid obtained by sulfonating an alkyl aromatic compound obtained by alkylating 1 to 10 moles, and a cation is derived from an alkali metal, a quaternary nitrogen group, or a calcium, magnesium, or barium sulfonate salt.

Overbased sulfonates according to this feature of the invention have a reduced tendency to froth, and neutral sulfonates that can be used as emulsifiers have improved stability, and these improvements have been found in most aromatic compounds. The inventors have found that this can be achieved. This method is particularly useful with benzene since the greatest foaming problems occur with alkylbenzenes. However, improvements are also obtained with toluene and xylene. The neutral sulfonates of the invention, particularly the salts of alkali metals or nitrogen bases, can be used as polymeric sulfonates in the emulsifier compositions described in my GB 1476891, resulting in oil-in-water emulsions. In particular, the inventors have found that suspensions have particularly good emulsion stability and are most useful as metalworking fluids.

When the cation of the sulfonates of the invention is an alkali metal, this cation is generally sodium; when it is a quaternary nitrogen group, the cation is an ammonium cation, but especially a quaternary amino Ethoxylated quaternary aminosulfonates have been found to be particularly useful surfactants. A major advantage of using mixed olefin feedstocks is in the production of overbased alkaline earth metal sulfonates for use as lubricant additives. In particular, the present invention is useful for producing overbased calcium sulfonates which, when used as lubricant additives, reduce the tendency of automotive crankcase lubricants to foam during motor operation.
Using overbased calcium sulfonates based on alkylates obtained midway through the process of the present invention, acceptable levels of froth can be obtained using conventional antifoam additives, which are similar to those based on other alkylates. This is a situation that does not occur with overbased additives,
Furthermore, the inventors have found that in some cases no antifoam additives are required.

The calcium sulfonate can be a neutral sulfonate or an overbased sulfonate, but it is with the overbased sulfonate that the greatest foaming problems occur, so the method has the greatest application in this case. These materials are generally prepared by neutralizing the sulfonic acid with lime in the presence of a reaction accelerator and then carbonating the reaction mixture to convert the excess calcium present to colloidal calcium carbonate. Various methods have been proposed for controlling viscosity and reaction rate, and alkylates such as those described above can be used in the production of sulfonic acids by any of these methods. Although primarily concerned with overcoming the foaming problem of overbased calcium sulfonates, the alkylates can also be used in the production of neutral and overbased magnesium and barium sulfonates.

The calcium, magnesium, and barium sulfonates are useful as lubricating oil additives, in the amounts commonly used and other well-known additives such as polyamine dispersants, viscosity index modifiers, and antiwear additives. Can be used in combination with The use of sulfonates derived from alkylates such as those described above produces lubricating oils with reduced tendency to froth compared to oils containing currently available sulfonates, and which contain some branched chain alkyl groups. A mixture of an alkylbenzene with a straight-chain alkyl group and an alkylbenzene with the other having a straight-chain alkyl group, in which both types of alkylates are prepared separately.Achieves the above effects with fewer straight-chain components than oils containing sulfonates based on the above mixtures. The present inventor has discovered that this can be done.

Example 1 85% by weight average _C24 branched propylene oligomer was mixed with 15% by weight _C24 linear olefin. 839 parts by weight of this olefin mixture were added to 1360 parts by weight of benzene in an alkylation vessel at 0°C containing 17 parts by weight of aluminum trichloride and 4 parts by weight of hydrochloric acid.
Keep the container at 0℃ for 30 minutes, then increase the temperature to 20℃ for 30 minutes.
Over time, the alkylate was allowed to settle, finally washed with sodium hydroxide and water and purified by distillation.

The alkylate thus obtained has a specific gravity of 0.860 at 15°C.
(measured by ASTM D1298), flash point 185° (ASTM
D92), a viscosity of 75 centistokes at 100°F (as measured by ASTM D445), and a molecular weight of approximately 420.

This alkylate was sulfonated with sulfur trioxide dissolved in sulfur dioxide, and the resulting sulfonic acid was isolated, purified, and converted to 300 TBN overbased calcium sulfonate by the method described in French patent no. Alkaline value expression (same below).

Example 2 The procedure of Example 1 was repeated except that the raw olefin mixture contained 80% by weight branched chain olefin and 20% by weight straight chain olefin.

Example 3 For comparison, benzene was separately alkylated with the straight chain olefin and branched chain olefin used in Example 1 using exactly the same alkylation conditions as used in Example 1.

an alkylate blend comprising 85% by weight of this branched chain alkylate and 15% by weight of the linear alkylate;
and other alkylate blends containing 80% by weight of the branched chain alkylate and 20% by weight of the linear alkylate were prepared.

Both blends were sulfonated as described in Example 1 to form 300 TBN overbased calcium sulfonate.

Example 4 5% by weight of the 300 TBN calcium high base number sulfonate of Examples 1-3 was combined into a standard control oil (SIS3453) and the oil was subjected to the standard ASTM D892 frothing test. This material was also compared to the same oil containing 5% by weight of 300TBN calcium sulfonate derived from _C24 branched chain alkylbenzene. The lubricants tested also contained the same amount of a conventional antifoam agent.

The test results were as follows.

Sulfonate test results Example 1 40/0 Example 2 T/0 Example 3 (i) 240/0 (ii) 20/0 C ₂₄ alkylbenzene 650/500 T indicates that only trace foam was formed .

Example 5 The foaming properties of a lubricant containing the product of Example 1 were compared to a lubricant containing calcium sulfonate obtained from _C24 branched chain alkylbenzene.
In this case, the lubricant did not contain an antifoam agent. The results were as follows.

Product of Example 1 410/320 C ₂₄ Alkylbenzene 650/500 Example 6 The sodium salt of the sulfonic acid of Example 1 was made by neutralization with sodium hydroxide, and the sodium salt of the sulfonate in dilute oil was prepared. The viscosity of the 70% by weight active ingredient solution was measured at 98.9°C. The viscosity of solutions containing increasing amounts of water was measured and compared to a similar solution containing a branched chain _C24 alkylbenzene sulfonate.

The test results are shown in the graph of FIG.

In other words, Figure 1 is a graph showing the relationship between the viscosity (centistokes, vertical axis) and water content (weight%, horizontal axis) at 98.9°C of sodium sulfonate salt (active ingredient 70% by weight), and the above curve A shows the case of a branched chain C ₂₄ alkylbenzenesulfonic acid, and lower curve B shows the case of the sodium salt of the acid of Example 1.

[Brief explanation of the drawing]

FIG. 1 shows the relationship between viscosity and water content for the test of Example 6.

Claims (1)

[Claims] 1. Up to 95% by weight of a branched chain olefin containing from 15 to 40 carbon atoms and at least 5% by weight of a straight chain olefin containing from 16 to 30 carbon atoms. sulfonic acid or sulfone of an alkylate, characterized in that the aromatic compound is alkylated and the alkylate is then sulfonated in a mixture with a molar ratio of the aromatic compound to the above-mentioned olefin mixture of 10:1 to 1:1. Method for producing acid salts. 2. The method for producing an alkylate sulfonate according to claim 1, wherein the cation is an alkali metal or a quaternary nitrogen group. 3. The method for producing an alkylate sulfonate according to claim 1, wherein the cation is calcium, magnesium, or barium. 4. A method for producing an alkylate sulfonate according to claim 1 or 3, wherein the sulfonate is overbased. 5. The method for producing an alkylate sulfonate according to claim 4, wherein the cation is calcium.