Low base number sulphonates

Details Low base number sulphonates Low base number sulphonates

1997-09-03

1998-09-08

Richter, Johann

Compositions

Electrolytes for electrical devices

252 33, 252 334, 252 39, 252 407, 252 332, 562115, C07C30302, C10M12900

Patent

active

058040943

DESCRIPTION:

BRIEF SUMMARY
This application is a 371 of PCT/EP96/00812 filed Feb. 27, 1996.
The present invention relates to low base number sulphonates and to processes for the production of these sulphonates. The invention also relates to oil based compositions containing these low base number sulphonates.
Basic or neutral sulphonates may be used as additives in lubricating oils for petrol engines and diesel engines for example for vehicles or marine engines. Neutral and low base number sulphonates function primarily as detergents to keep engine surfaces clean. High base number sulphonates are primarily used to neutralise acids produced in the oil during use. These sulphonates may help to inhibit corrosion.
Neutral and low base number sulphonates for use as oil additives are usually prepared by the neutralisation of a sulphonic acid with a basic salt such as a basic calcium salt e.g. calcium oxide or hydroxide in a suitable diluent oil. The sulphonate product may be a mixture of a number of species. In addition dispersed calcium hydroxide may be present.
The product of this process may display some basicity, for example if the basic salt is added in stoichiometric excess to that required for complete neutralisation of the sulphonic acid, or some other basic component is present. The product in this case is said to be overbased.
The neutral metal salts of typical sulphonic acids are extremely viscous materials and would have a TBN, as measured by ASTM D-2896, of zero. Methods have been sought which permit lower viscosity products to be prepared. This has been achieved by the incorporation of chloride, formate and hydroxide ions into the product. The products of these techniques are not truly neutral but are slightly overbased in that they contain more base than that required to react stoichiometrically with the sulphonic acid.
In particular, it is difficult to produce low base number sulphonates from synthetic high molecular weight sulphonic acids, ie synthetic acids of average molecular weights of 500 or greater, which also have low viscosity. If this is attempted, high viscosity soaps or high viscosity sulphonates are produced which have a lower than expected base number. One way of overcoming this, as indicated previously, is by adding more base which tends to reduce viscosity and increase the base number of the product. However this addition of for example excess Ca(OH).sub.2 produces free hydroxyl which is believed to be associated with a skinning effect on exposure to air on the surface of the sulphonate. Skinning is an undesirable property of low base number sulphonates. Viscosity can be controlled to some extent by the addition of halide as outlined above.
U.S. Pat. No. 4,764,295 discloses a process for the production of low base number sulphonates from sulphonic acids which have alkyl radicals of C.sub.15 to C.sub.40 ; the process utilises chloride containing salts and carboxylic acids such as formic acid. The products have relatively low viscosity but contain chloride.
High base number sulphonates are generally prepared by a process of neutralisation with excess base (overbasing) followed by carbonation. Typically the sulphonic acid is neutralised with excess basic metal oxide or hydroxide in a suitable diluent. Some of the excess basic metal oxide or hydroxide is converted to metal carbonate via carbonation. Typically the reaction is carried out in the presence of hydrocarbon and/or polar solvents such as toluene/methanol and diluent oil; some or all of these solvents may be subsequently removed. The resulting product is a colloidal dispersion, in a diluent oil, of sub-micron particles of CaCO.sub.3 and Ca(OH).sub.2 which are sterically stabilised by the calcium sulphonate species produced by the reaction.
Sulphonates have been prepared from synthetic sulphonic acids which have in turn been prepared for example by the sulphonation of C.sub.12 to C.sub.60+ alkyl substituted benzene, or xylene or toluene compounds and mixtures thereof. It has been found that some synthetic sulphonic acids are difficult to neutralise with f

REFERENCES:
patent: 4764295 (1988-08-01), Le Coent
patent: 5281345 (1994-01-01), Crawford et al.
patent: 5684184 (1997-11-01), Alcock et al.

Affiliated with

Also associated with

Rating

Low base number sulphonates does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Low base number sulphonates, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Low base number sulphonates will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1279013