GB1585056A

GB1585056A - Phosphosulphurised terpenes

Info

Publication number: GB1585056A
Application number: GB25391/76A
Authority: GB
Original assignee: Exxon Research and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 1977-06-15
Filing date: 1977-06-15
Publication date: 1981-02-25

Description

(54) IMPROVED PHOSPHOSULPHURISED TERPENES (71) We, EXXON RESEARCH AND ENGINEERING COMPANY, a Corporation duly organised and existing under the laws of the State of Delaware, United States of America, of Linden, New Jersey, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to improved phosphosulphurised terpenes. The condensation products of terpenes, especially ci-pinene, and P2S5 are well known as is their use as additives for lubricating oils where they impart anti-corrosion and anti-oxidant properties to the lubricating oil. However, the condensation products hitherto known suffer from the disadvantage that they tend to form a haze and deposit a sediment when left to stand. This is of course a disadvantage in lubricating oils whose clarity is important and where sediment formation can be a danger.

It has been proposed in British Patents 679296 and 700303 that sulphur may be included in the reaction of P2S5 with a terpene to give improved antioxidant properties. We have found this to be so and have also found that the presence of the sulphur tends to overcome the problems of haze and sediment formation. We found however that the presence of the sulphur increases the extent to which a lubricating oil containing the product corrodes copper and lead which is a significant disadvantage since many bearings in engines where the lubricants are used contain copper and lead. In addition oils containing the material tend to generate H2S which is both toxic and leads to an unpleasant smell.

We have now found however that if an oil-soluble amine is present during the reaction of the terpene, P2S5 and sulphur the extent to which the product corrodes copper is considerably reduced as is the generation of H2S Whilst the improved antioxidancy and reduced hazing and sediment formation are retained.

The present invention therefore provides as a new composition of matter the reaction product of a terpene, a phosphorus sulphide, elemental sulphur and an oil-soluble amine characterised in that the constituents have been reacted in the ratio from 3 to 6 moles of the terpene, from 0.1 to 2.5 gram atoms of sulphur and from 1% to 5% by weight of the oil soluble amine based on the weight of the terpene for each mole of the phosphorus sulphide.

The invention also provides lubricant compositions containing a major proportion by weight of a lubricating oil and a minor amount by weight of a compound according to the present invention. We prefer that the lubricant composition contains from 0.1% to 10% by weight of the compound more preferably from 0.5% to 2.5% by weight.

The present invention also provides a concentrate comprising from 90% to 20% by weight of a diluent oil and from 10% to 80% by weight of a compound according to the present invention. In particular we prefer that the concentrate comprise from 20% to 60% by weight of the diluent oil and from 80% to 40% by weight of the compound.

The concentrate and lubricating compositions of the present invention may also contain other conventional oil additives such as dispersants, anti-wear, anti-rust and anti-corrosion additives.

The present invention also provides a process comprising reacting a terpene, sulphur, a phosphorus sulphide and an oil-soluble amine at a temperature in the range 1200C to 1800C characterised in that from 3 to 6 moles of the terpene from 0.1 to 2.5 gram atoms of sulphur and from 1% to 5% by weight of the oil-soluble amine based on the weight of the terpene are present for each mole of the phosphorus sulphide.

The phosphorus sulphide used in the techniques of the present invention is preferably phosphorus pentasulphide.

Any suitable terpene may be used in the product of the present invention and examples include ot-pinene, camphene, delta-3-carene, di-pentene and the various isobutylene oligomers where the product is to be used in a lubricating oil however we prefer that the terpene be a-pinene since this product generally has improved oil solubility.

The function of the amine is not fully known but it is important that it be present during the formation of the product. We find that the advantages described for our material are not achieved by simple blending of a terpene/P2Ss/ sulphur reaction product and an amine as could occur in the techniques of British Patents 679296 and 672875 where terpene /P2S5/ sulphur reaction products are included in lubricating oils which also can contain amines.

The amine should be a primary or a secondary amine and any oil-soluble primary or secondary amine may be used. Generally we prefer to use an aliphatic amine containing at least eight carbon atoms.

The incorporation of sulphur in the phosphosulphurization of the terpene accelerates the reaction and also produces complex compounds which have improved antioxidancy as compared to terpenes phosphosulphurized in the absence of sulphur and the presence of the sulphur tends to reduce haze and sediment formation in lubricating oils containing the material. However the extent to which the products corrode copper and generate H2S is increased. The presence of the amine overcomes these disadvantages. The process of the present invention may be carried out by adding a mixture of the phosphorus sulphide and sulphur and the amine to a mixture of the terpene and the amine held at the appropriate temperature. Alternatively sulphur may be added first to the heated terpene containing the amine and then the phosphorus sulphide added. The reaction is preferably carried out in a solvent to overcome the problems of glass formation and when the product of the present invention is to be used as an additive for lubricating oils we prefer to use a diluent oil as the solvent so that there is no need to remove the solvent prior to incorporation of the product in the lubricating oil in this situation. The choice of amine will depend on the nature of the diluent oil since it should be soluble in the oil.

Our preferred reaction conditions comprise dissolving the desired amount of the terpene and the amine in a diluent oil which is heated to a temperature in the range 1200C to 1500C, preferably 1200C to 138"C, generally under a blanket of inert gas such as nitrogen. The phosphorus pentasulphide and the sulphur are mixed and the mixture added slowly to the solution of the terpene and the amine whilst ensuring that the temperature does not rise above 1500C and preferably remains below 140"C. When addition of the phosphorus pentasulphide-sulphur mixture is complete the reaction mixture is maintained at the reaction temperature for some time, generally 1 to 3 hours and then vacuum stripped to remove low boiling products and the product purified by filtration.

The products of the present invention are particularly useful as antioxidants in lubricating oils. The lubricating oil may be any animal, vegetable or mineral oil for example petroleum oil fractions ranging from naphthas to spindle oil to SAE 30, 40 or 50 lubricating oils or oxidised mineral oils. Although the compositions are generally mineral oils they are also applicable to synthetic ester lubricating oils for example the diesters such as di-octyl adipate, dioctyl sebacate; didecyl azelate, tridecyl adipate, didecyl succinate, didecyl glutarate and mixtures thereof. Other synthetic ester oils to which the invention is applicable include those prepared by reacting polyhydric alcohols such as trimethylol propane and pentaerythritol with monocarboxylic acids such as butyric acid, caproic acid, caprylic acid and pelargonic acid.

We have found that in order to obtain the desired antioxidant properties the lubricating composition of the present invention should contain between 0.1% and 10% preferably from 0.1 to 5% by weight of the composition of the present invention. The product may however be supplied as a concentrate of the composition of the present invention in oil which is supplied for incorporating into bulk lubricating oil. In this instance the concentrate may contain up to 80% preferably from 5% to 60% and more preferably from 5% to 70% of the composition of the present invention.

The lubricating composition or the concentrate may contain any of the other types of additives that are generally included in lubricating oils. For example the composition may contain ashless dispersants such as the polyamine-long chain mono- or dicarboxylic acid or acid anhydride condensation products. Any of the well-known dispersants may be used and examples include the condensation products of esters, amides, or imides of dicarboxylic acids or anhydrides or tri and higher polycarboxylic acids and anhydrides said acid or anhydride having at least 30 atoms per molecule with a polyamine. Thus, the acid or anhydride may have a molecular weight of about 500 and preferred acids or anhydrides are those having a molecular weight of betwen 600 and 3000, e.g. between 800 and 1800. These carboxylic acids and anhydrides are conveniently derived from a polymer of a mono-olefin e.g. a C2 to Cs mono-olefin e.g. a C2 to C5 mono-olefin, such as polyethylene, polypropylene or polyisobutene.

Dicarboxylic acid anhydrides having a relatively long chain may conveniently be made by the reaction of maleic anhydride with a long-chain olefin or a halogneated long-chain olefin.

The preferred olefins are polymers of mono-olefins, especially those described above with reference to making long-chain mono-carboxylic acids. Thus, one may react a polyisobutene of molecular weight between 600 and 3000 or the halogenated derivative thereof with maleic anhydride to give an alkenyl su'ccinic anhydride. The two reactants may be merely heated together at a temperature of between 1500C and 200"C. The corresponding acids can be made by hydrolysing the anhydrides. A particular example of a long chain dicarboxylic acid is polybutenyl succinic acid of MW approximately 1000.

The amide or imide is derived from a polyamine and this is preferably a polyalkylene polyamine. Suitable polyalkylene polyamines include those of the formula: (H2N(CH2)n)rn (NH(CH2)n)rn - NH(CH2)jiNH2 where n is 2 or 3 and m is zero or an integer of 1 to 10. Thus suitable polyalkylene polyamines are the polyethylene and polypropylene polyamines such as diethethylene triamine, triethylene tetramine, tetraethylene pentamine, octaethylene nonamine and tetrapropylene pentamine.

Preferred examples are the reaction products of polyisobutenyl succinic anhydride of molecular weight between 600 and 3000 e.g. about 1000, and a polyethylene polyamine, e.g. tetraethylene pentamine. These reaction products are usually mixtures of amide and imide, mainly imide. Thus one may use the reaction product of polyisobutenyl succinic anhydride (MW about 1000) and tetraethylene pentamine in a mole ratio of 1.3:1 respectively. This amide/imide mixture has a nitrogen content of 2.1-2.4 wit. % and a Total Base Number (TBN), being the number of milligrams of KOH equivalent to 1 gram of the product when titrated with strong acid, of about 50. One could also use the reaction product of polyisobutenyl succinic anhydride (MW about 1000) and tetraethylene pentamine in a mole ratio of 2.1:1 respectively. This amide/imide mixture has a nitrogen content of at least 1.45 wt. %, typically 1.5 to 1.6 and a TBN of 25 to 35. Another particularly suitable example is the reaction product of polyisobutenyl succinic anhydride (MW about 1000) and tetraethylene pentamine in a mole ratio of 2.8:1. This amide/imide mixture has a nitrogen content of about 1.2 wt.% and a TBN of about 22.

As alternatives to the above mentioned amide/imide mixtures one could use them after they have been reacted with boric acid. In some circumstances these borated dispersants show certain advantages, e.g. better control over piston deposits in diesel engines. These borated dispersants are also amide/imide mixtures which may be prepared by reacting the dispersant with boric acid to give a boron content in the finished dispersant of from 0.05 to 1.0 wt.%.

Other additives that may be present include highly basic dispersants such as the overbased calcium and magnesium sulphonates and phenates as may other conventional antioxidants such as the zinc dithiophosphates. Other additives that may be incorporated in the lubricating composition include viscosity index improvers such as ethylene-vinyl acetate copolymers or other olefin copolymers based on ethylene and antiwear additives such as the sulphur-containing heterocyclic compounds and antirust additives such as dodecyl succinic acid or the sulphurised alkyl dihydroxy benzenes as disclosed in United States Patent 4115287. Some or all of these other additives may be included in the concentrate when the composition of the present invention itself is supplied as a concentrate.

The present invention is illustrated but in no way limited by the following examples, Examples 1 to 3 and Example 5 when related to Examples 1 to 3 being by way of comparison.

Example 1 272 grams of a -Pinene were dissolved in 208 grams of a solvent extracted paraffinic mineral oil of viscosity 150 centistokes at 1000F and the mixture heated to 1250C under a blanket of nitrogen. 111 grams of P2S5 were then added slowly whilst ensuring that the temperature of the mixture did not rise above 140"C. After completion of the addition, the mixture was heated first at 1400C for one hour and then at 1500C for a further hour. The product was then stripped to remove unreacted a-pinene and filtered.

The product was a pale golden mobile liquid containing 14.5 wt.% sulphur and 5.4 wt.% phosphorous.

Example 2 The process of Example 1 was repeated except that 16 grams of sulphur were included in the initial a-pinene solution and the P2S5 was added over a period of 5 hours whilst the mixture was held at a temperature below 130to. After P2S5 addition the reactor was heated at 1300C for one hour.

The product was a clear brown mobile liquid containing 17.2 wt.% and 5.4 wt.% phosphorous.

Example 3 The process of Example 2 was repeated except that on completion of P,S5 addition the reactor was heated 1500C for one hour and then at 1600C for a further hour.

The product was a clear, dark brown mobile liquid containing 17.4 wt.% sulphur and 5.3 wt.% phosphorus.

Example 4 Example 2 was repeated except that 9.6 grams of the commercially available amine based on a C12 branched alkyl chain and known as "Primene" (Registered Trade Mark) 81-R" were included in the a -Pinene, sulphur solution.

The product was a clear brown mobile liquid containing 17.6 we. % sulphur and 5.3 wt.% phosphorus.

Example 5 The products of Example 1 to 4 were dissolved in a mineral lubricating oil of viscosity 150 centistokes at 1000F and the oils subjected to the following tests.

1) "H2S demerit" - in this test 800 grams of oil containing 1 wt. % of the products is placed in a sealed bottle and heated to 1000F for 1 hour. The stopper of the bottle is then removed and the outlet covered with lead acetate paper and the colour of the paper given a rating.

The higher the rating the darker the paper and the more H2S produced from the oil composition 2) The "Copper corrosion" test ASTM D130 in which a polished copper strip is immersed in oil heated to 100 C for 3 hours after which the appearance of the copper strip is given a visual rating according to ASTM D 130.

3) The oxidation stability is measured by the "Mod COT" test in which 0.5 wit. % sulphated ash MIL-L.46152 oil containing 1.7 wt.% of the products and 0.1 wt.8/s iron naphthenate is stirred with a paddle made from a Petter W-1 engine bearing with air blowing at 1710C and then the percentage change in viscosity after 30 and 48 hours measured.

4) The corrosive effect on engine bearings was measured using two samples of the MIL-L-46152 0.5 wt.% sulphated ash oil one containing 1.0 wt.% of the products and the other 1.7 wt.% according to the Labeco -CLR- L 38 bearing corrosion test.

The results were as follows Product of H2S Demerit Copper Strip Mod COT L38 Example Rating (ASTM D130)Viscosity Increase Bearing weight Loss (Miliigrams) 30 hrs. 48 1.0 wt.% 1.7 wt.% 1 0.5 3b 17 > 250 53.4 51.3 2 5.0 3b 2 41 74.6 118 3 5.0 3b 3 81 54.5 102 4 0.0 3a 3 66 47.5 41.7 Example 6 Comparative tests were carried out using the bench bearing corrosion test (SAE Publication 680538) on a MIL 46152 0.5 wt.% sulphated ash oil containing 1.7 wt.% of the additives described in the following table with the results as follows: Additive Colour of Bearing Wt. Loss Example 2 Multi-coloured 4 mg Example 2 and Primeme Multi-coloured 3.8 mg 81-R Example 4 Bronze 0 WHAT WE CLAIM IS: 1. A reaction product of a terpene, a phosphorus sulphide, elemental sulphur and an oil-soluble amine characterised in that the constituents have been reacted in the ratio from 3 to 6 moles of the terpene, from 0.1 to 2.5 gram atoms of sulphur and from 1% to 5% by weight of the oil-soluble amine based on the weight of the terpene for each mole of the phosphorus sulphide.

2. A reaction product according to claim 1 in which the phosphorus sulphide is phosphorus pentasulphide.

3. A reaction product according to claim 1 or claim 2 in which the terpene is a - pinene.

4. A reaction product according to any one of the preceding claims in which the amine is a primary or secondary aliphatic amine containing at least eight carbon atoms.

5. A reaction product according to claim 1 substantially as hereinbefore described with particular reference to Example 4.

6. A process for the preparation of a reaction product according to any one of the preceding claims comprising reacting a terpene, sulphur, a phosphorus sulphide and an oil-soluble amine at a temperature in the range 1200C to 1800C characterised in that from 3 to 6 moles of the terpene, from 0.1 to 2.5 gram atoms of sulphur and from 1% to 5% by weight of the oil-soluble amine based on the weight of the terpene are present for each mole of the phosphorus sulphide.

7. A process according to claim 6 in which the terpene and the amine are dissolved in a diluent oil at a temperature in the range 1200C to 1500C and a mixture of the phosphorus sulphide and sulphur added to this solution whilst ensuring that the temperature does not rise above 1500C and maintaining this mixture at a temperature in the range 1200C to 1500C for from 1 to 3 hours.

8. A process according to claim 6 substantially as hereinbefore described with particular reference to Example 4.

9. A reaction product whenever produced by a process according to any one of claims 6 to 8.

10. A lubricant composition containing a major proportion by weight of a lubricating oil and a minor amount by weight of a reaction product according to any one of claims 1 to 5 and 9.

11. A lubricant composition according to claim 10 containing from 0.1 to 10% by weight of the reaction product.

12. A lubricant composition according to claim 10 substantially as hereinbefore described with particular reference to Example 5.

13. A concentrate comprising from 90 to 20% by weight of a diluent oil and from 10% to 80% by weight of a reaction product according to any one of claims 1 to 5 and 9.

14. A concentrate according to claim 12 containing from 80% to 40% by weight of the reaction product.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

Example 6 Comparative tests were carried out using the bench bearing corrosion test (SAE Publication 680538) on a MIL 46152 0.5 wt.% sulphated ash oil containing 1.7 wt.% of the additives described in the following table with the results as follows: Additive Colour of Bearing Wt. Loss Example 2 Multi-coloured 4 mg Example 2 and Primeme Multi-coloured 3.8 mg

81-R Example 4 Bronze 0 WHAT WE CLAIM IS: 1. A reaction product of a terpene, a phosphorus sulphide, elemental sulphur and an oil-soluble amine characterised in that the constituents have been reacted in the ratio from 3 to 6 moles of the terpene, from 0.1 to 2.5 gram atoms of sulphur and from 1% to 5% by weight of the oil-soluble amine based on the weight of the terpene for each mole of the phosphorus sulphide.
2. A reaction product according to claim 1 in which the phosphorus sulphide is phosphorus pentasulphide.
3. A reaction product according to claim 1 or claim 2 in which the terpene is a - pinene.
4. A reaction product according to any one of the preceding claims in which the amine is a primary or secondary aliphatic amine containing at least eight carbon atoms.
5. A reaction product according to claim 1 substantially as hereinbefore described with particular reference to Example 4.
6. A process for the preparation of a reaction product according to any one of the preceding claims comprising reacting a terpene, sulphur, a phosphorus sulphide and an oil-soluble amine at a temperature in the range 1200C to 1800C characterised in that from 3 to 6 moles of the terpene, from 0.1 to 2.5 gram atoms of sulphur and from 1% to 5% by weight of the oil-soluble amine based on the weight of the terpene are present for each mole of the phosphorus sulphide.
7. A process according to claim 6 in which the terpene and the amine are dissolved in a diluent oil at a temperature in the range 1200C to 1500C and a mixture of the phosphorus sulphide and sulphur added to this solution whilst ensuring that the temperature does not rise above 1500C and maintaining this mixture at a temperature in the range 1200C to 1500C for from 1 to 3 hours.
8. A process according to claim 6 substantially as hereinbefore described with particular reference to Example 4.
9. A reaction product whenever produced by a process according to any one of claims 6 to 8.
10. A lubricant composition containing a major proportion by weight of a lubricating oil and a minor amount by weight of a reaction product according to any one of claims 1 to 5 and 9.
11. A lubricant composition according to claim 10 containing from 0.1 to 10% by weight of the reaction product.
12. A lubricant composition according to claim 10 substantially as hereinbefore described with particular reference to Example 5.
13. A concentrate comprising from 90 to 20% by weight of a diluent oil and from 10% to 80% by weight of a reaction product according to any one of claims 1 to 5 and 9.
14. A concentrate according to claim 12 containing from 80% to 40% by weight of the reaction product.