FR2512029A1 - PROCESS FOR THE PREPARATION OF DITHIOPHOSPHORIC ACID SALTS - Google Patents

Abstract

THE INVENTION RELATES TO A PROCESS FOR THE PREPARATION OF SALTS OF DITHIOPHOSPHORIC ACIDS. THIS PREPARATION IS PERFORMED BY NEUTRALIZATION OF DITHIOSPHORIC ACIDS USING BASIC-REACTING METAL COMPOUNDS IN THE PRESENCE OF ONE OR MORE QUATERNARY AMMONIUM COMPOUNDS INCLUDING THE RRRRN GROUP IN WHICH R, R, R AND R MAY BE THE SAME OR DIFFERENT AND REPRESENT A HYDROGEN ATOM OR AN ALKYL, ARYL, ALKARYL OR ARALCOYL GROUP IS SUBSTITUTE OR NOT, PROVIDED THAT AT LEAST ONE OF THEM IS NOT A HYDROGEN ATOM. USE OF THE PRODUCTS AS ADDITIVES IN LUBRICATING COMPOSITIONS.

Description

The present invention relates to a process for the preparation of salts

  The invention relates in particular to the preparation of zinc dithiophosphates by the neutralization of dithiophosphoric acids using suitable zinc compounds. The present invention also relates to a process for reducing the number of dithiophosphoric acids by the use of dithiophosphoric acids. process for the preparation of lubricating compositions comprising one or more dithiophosphoric acid salts prepared by the process according to the invention, and the lubricating compositions thus prepared. Salts of dithiophosphoric acids, and in particular zinc dithiophosphates, are used in a

  generally in lubricating compositions such as

  oxidants and in particular as extreme additives

pressure / anti-wear (EP / AW).

  The dithiophosphoric acid salts are generally prepared by neutralizing dithiophosphoric acids which in turn are usually prepared according to the following reaction equation (1):

  4 ROH + P 255 -> 2 (RO) 2 P SH + H 2 S (1)

  wherein R is a substituted or unsubstituted hydrocarbyl group The subsequent neutralization reaction giving, for example, zinc dithiophosphates can be represented by the reaction equation (2):

S S

  2 (RO) 2 P SH + Zn Xq ((RO) 2 PS) 2 Zn + H 2 Xq (2) where X is a portion O, OH or C 03 and q = 1 when X is a bivalent portion and q = 2 when X is a

monovalent portion.

  It is well known in the art that neutralization

  of dithiophosphoric acids in accordance with

  the reaction equation (2) proceeds rather slowly.

  It requires a large excess of the metal compound (eg zinc oxide) for the reaction to proceed satisfactorily, which at the same time entails the disadvantage that the product loses much of its maneuverability in Particularly its filterability Especially the preparation of salts of dialkyl dithiophosphoric acids containing relatively long alkyl chains (e.g. chains of eight or more carbon atoms)

presents this problem.

  In US Pat. No. 4,085,053, it has been proposed to reduce the excess of the metal compound to be used by conducting the reaction in the presence of an acid promoter (hydrochloric acid, perchloric acid or nitric acid Y and reacting then a considerable proportion of the excess acid promoter used with a weak base, preferably ammonia or urea A smaller

  amount of metal compound will then be

  health, but at the same time the proposed process is more complicated because of the additional reaction step it involves, and moreover it requires a molar excess

double to triple low base.

  In US Pat. No. 3,471,540, it has been proposed to carry out the neutralization in the presence of an aromatic nitrogen compound (for example pyridine) as a diluent. This proposal has the disadvantage that it is necessary to use separation consuming a large amount of energy to remove reaction mixture the

  large amount of nitrogen compound used.

  It has now been found that dithiophosphoric acid salts can be prepared in an improved manner by conducting the neutralization reaction in accordance with

  equation (2), in the presence of a quaternary ammonium compound

  Not only can stoichiometric amounts of the basic reaction metal compounds (or even smaller amounts) be used very well, but the reaction is also rapid and can be carried out advantageously using very small amounts of

  quaternary ammonium compounds, which allows

  considerably less complicated of the reaction product. The present invention therefore relates to a process for the preparation of dithiophosphoric acid salts by neutralization of dithiophosphoric acids using basic reaction metal compounds in the presence

  of one or more compounds of quaternary ammonium

  1234 E Li 2 3 4 preferably the group RR 2 R 3 R 4 N-, oR, R, R and R may be identical or different and represent a hydrogen atom or a substituted or unsubstituted alkyl, aryl, alkaryl or aralkyl group , with the condition that at least

  one of them is not a hydrogen atom.

  Dithiophosphoric acids which can very well be used as starting material in the process according to the invention can be represented by the general formula (3):

RA O S

R P SH (3),

RB _ P> H

  in which RA and RB, which may be identical or

  different, each represents an alkyl group, a cyclo-

  alkyl, aryl, alkaryl or aralkyl of 2 to 20 carbon atoms Examples of such compounds include

  ethylpropyldithiophosphoric acid, methylbutyldithio-

  phosphoric acid, ethyldecyldithiophosphoric acid,

  dipropyldithiophosphoric acid, di-isobutyldithiophos-

  phoric acid, didecyldithiophosphoric acid, di-

  isodecyldithiophosphoric acid, dimyristyldithiophos-

  phoric, dieicosadithiophosphoric acid, acid

  butylphenyldithiophosphoric acid, decylbenzyldithio-

  phosphoric acid, propylcyclohexyldithiophosphoric acid, -4-

  diphenyldithiophosphoric acid, dibenzyl

  dithiophosphoric acid, dicyclohexyldithiophosphoric acid,

  dicyclodecyldithiophosphoric acid and di-acid

  butylphenyl) dithiophosphoric Compounds of formula (3) in which RA and RB are identical are preferably used because such compounds can easily be obtained according to the general reaction equation (1). Examples of such compounds include the acid

  didecyldithiophosphoric acid, di-isodecyldithiophos-

  phoric, dimyristyldithiophosphoric acid, acid

  diphenyldithiophosphoric acid, dibenzyldithiophosphoric acid

  and dicyclohexyldithiophosphoric acid.

  Another group of dithiophosphoric acids used

  Sand as starting material can be represented by the general formula (4): R O (C 2 H 4 O) (C 3 H 6 O) y S

P SH (4)

B R O (C 2 H 40) p (C 3 H 6 O) q

  in which R and R have the meaning described above.

  above and p q, x and y are integers included

  between 0 and 10, the sum of p, q, x and y being at least 1.

  Examples of polyalkyl compounds of formula (4) include compounds wherein p = x and q = y, wherein p, q, x and y are each an integer from 0 to 6, and wherein RA and RB are preferably identical and represent alkyl groups of 8 to 20 carbon atoms, in particular of 9 to 15 carbon atoms. Mixtures of compounds of formulas (3) and / or (4) in which RA and RB may or may not have the same meaning may also be used as a starting material in practice (particularly in the case of compounds in which RA and RB contain a number -5-

  relatively large number of carbon atoms) of the alcohols available

  commercially available will often be used in the preparation of dithiophosphoric acids in accordance with the general reaction equation (1), so that mixtures are often used.

  alkoxylation (represented by p, q, x and y in the form of

  mule (4)) will also vary All these compounds can be

  used without any problem as starting materials.

  The metal compounds which can be used in the preparation of dithiophosphoric acid salts according to the process of the invention comprise compounds of groups IIA and IIB of the Periodic Table of the Elements. In particular, it is possible to use zinc compounds, cadmium compounds, magnesium, calcium, strontium and barium. Examples of such compounds include zinc oxide, zinc hydroxide, zinc carbonate, cadmium hydroxide, magnesium oxide, sodium hydroxide and the like. magnesium, calcium oxide, calcium carbonate,

  barium oxide and barium carbonate

  the use of zinc oxide.

  Examples of quaternary ammonium compounds which can be advantageously used in the process according to the present invention include compounds containing the group RRR 3 RN wherein R, R, R and R, which may be the same or different. different, represent each

  a hydrogen atom or an alkyl or aryl group

  or not, the total number of carbon atoms being at least 1 and not more than 60, as

  ethylammonium, n-butylammonium, t-butylammonium, nonyl

  ammonium, decylammonium, isodecylammonium, phenylammonium, benzylammonium, diethylammonium, di-t-butylammonium, dinonylammonium, diphenylammonium, tetramethylammonium,

  tetrabutylammonium, tetra-t-butylammonium, octyltrimethyl-

  ammonium, tetradecyltrimethylammonium, hexadecyltributyl-

  Ammonium and benzyltrimethylammonium Compounds that can be used are ammonium halogenide quaternary, in particular chlorides and bromides, and also nitrates, sulphates and perchlorates. A preference is given to the use of chlorides and bromides of compounds having at least four and preferably eight or more carbon atoms in the molecule, such as

  tetramethylammonium chloride, tetramethyl bromide

  ammonium chloride, dinonylammonium chloride, tetrabutylammonium chloride, tetrabutylammonium bromide and

  octyltrimethylammonium chloride.

  Substituted substituents are halogens and alkoxy, aryloxy and amino groups. Examples of such compounds include halogenated alkylammonium compounds and alkylammonium and arylammonium compounds containing groups

  methoxy and ethoxy When the ammonium compounds quater-

  are often available in the form of the corresponding di or polyonium compounds, such as 1,2-diaminoethane dihydrochloride, 1,4-diaminobutane dihydrobromide and triethylenetetramine halogenhydrates and compounds of the same kind. Good results are obtained when using 1,2-diaminoethane dihydrochloride as the

quaternary ammonium compound.

  The method according to the invention can be implemented in

  using the reactants in stoichiometric amounts

  It can also be carried out using less than the theoretical amount of the basic reaction metal compound. When the neutralization is carried out so that the converted dithiophosphoric acid is not completely neutralized, however, the amount of the reaction metal compound basic still present can

  be eliminated in a simple way, for example by

  fugation, which will greatly improve -7-

  susceptibility of treatment of the reaction product.

  The amount of quaternary ammonium compound to be used is not critical; it can vary between

  wide limits One can very well use

  between 0.01% by weight and 10% by weight, relative to the dithiophosphoric acid used. Quaternary compound amounts of between 0.1% by weight and 5% by weight are preferably used. 'acid

dithiophosphoric acid introduced.

  The dithiophosphoric acids to be used as the starting material can be prepared by methods known in the art. For example, they can very well be obtained according to reaction equation (1) from phosphorus pentasulfide and the desired alcohol. Generally, alcohols having the formula R OH and / or R OH are used, where R and R have the meaning described above, so that compounds of formula (3) are formed. Alcohols or mixtures of alcohols contain Suitably up to 20 carbon atoms are used. Usually about 4 moles of alcohol are reacted per mole of phosphorus pentasulfide to

  obtain optimum yields of dithiophosphoric acid

  In practice, the reaction is carried out at an elevated temperature, for example at temperatures up to 1500 ° C., for several hours. Anhydrous alcohols are preferably used. The use of alcohol mixtures usually leads to the formation. acids

mixed dithiophosphoric compounds.

  The reaction of dithiophosphoric acid with

  basic reaction metal can very well be

  at room temperature Higher temperatures, for example temperatures up to 2000 C, may also be used, but because of the presence

  of the quaternary ammonium compound, they are usually not

  Not normally required, the metal compound is added to the dithiophosphoric acid while stirring.

  If desired, the reaction can be carried out in advance.

  If a diluent is present which renders the reaction mixture easier to stir Suitable diluents are hydrocarbons, such as hexane, heptane, octane and similar compounds. The reaction can also be conducted in the presence of of a lubricating oil In this case,

  preference is given to the use of lubricating oils.

  who play the role of base oils for

  usual additives including metal dithiophosphates.

  More particularly, the lubricating oil is a mineral lubricating oil obtained by solvent extraction or hydrotreatment. Synthetic hydrocarbon lubricating oils and other synthetic lubricating oils can also be used very well Depending on the crude oil from which they come, the lubricating oils

  minerals may be of a naphthenic, paraffinic

  Mixed lubricating oils are lubricating oils having a

  low, medium or high viscosity index.

  The process according to the present invention may be carried out batchwise or (semi-continuous). When the process is carried out in a batch manner, a slurry of the basic reaction metal compound in

  diluent or in a lubricating oil may be

  in a reaction vessel containing the acid

  dithiophosphoric acid and the quaternary ammonium compound.

  When the process is carried out continuously, the reactants and the quaternary ammonium compound can be introduced into the reactor together or separately,

  while there is a continuous evacuation of product.

  The reaction products may very well be treated by methods well known in the art. If desired, additional methods of purification may be used, for example

  earth for the adsorption of insoluble constituents.

  The present invention also relates to a process for the preparation of lubricating compositions comprising one or more dithiophosphoric acid salts prepared

  by neutralization of dithiophosphoric acids in use

  reading basic reaction metal compounds in pre-

  the presence of one or more quaternary ammonium compounds

1234 R-1 23

  comprising the group R may be the same or different and represent a hydrogen atom or a substituted or unsubstituted alkyl, aryl, alkaryl or aralkyl group, with the proviso that at least

  one of them is not a hydrogen atom.

  In particular, this invention relates to a process for the preparation of lubricating compositions comprising one or more dithiophosphoric acid salts prepared by neutralization of dithiophosphoric acids of the general formulas (3) and / or (4) wherein R, RB and q are significance as described above, with basic reaction metal compounds, in particular zinc compounds, in the presence of one or more quaternary ammonium compounds including the group RRRRN -, oR, R

  R and R 4 have the meaning described above.

  The present invention also relates to lubricating oil compositions which, in addition to a major amount of lubricating oil, comprise a minor amount of one or more dithiophosphoric acid salts obtained by neutralizing dithiophosphoric acids of the formulas (3). and / or (4) RA, RB, p, q, x and y have the meaning described above, with basic reaction metal compounds, preferably zinc compounds, in the presence of one or more compounds of quaternary ammonium comprising 1234 E i 2 3 4 the group RRRRN, o R, R, R and R have the meaning

described above.

-10-

  The lubricating oil composition preferably comprises

  from 0.5 to 99.95% by weight of one or more mineral and / or synthetic lubricating oils and from 0.05 to 15%

  by weight of one or more salts of dithiophosphoric acid

  prepared according to the process of the present invention. The lubricating oil to be used is preferably a VHI-160 B oil. Naturally, the lubricating oil composition may also contain other additives, for example viscosity index improvers, point depressors.

  flow, antifoam agents, surfactants,

  active ingredients, anti-oxidants, anti-rust additives, etc. The present invention is now illustrated in

using the following examples.

Example 1

  A solution of 8.2 g (20 mmol) of di-isodecyl

  dithiophosphoric acid (the initial concentration of which was determined by titration with 0.1 N tetrabutylammonium hydroxide in isopropanol) and 0.07 g (0.4 mmol) of nonylammonium chloride in 50 cm 3 of diethyl ether. 60/80 petroleum is introduced into a reaction vessel equipped with a magnetic stirrer. Then, 0.78 g (9.6 mmol) of zinc oxide are added all at once.

  vigorously agitated solution After 10 minutes,

  undermines conversion level by taking a sample

  2 cm 3 and determining the percentage of dithio-

  phosphoric acid still present by titration with 0.1 N tetrabutylammonium hydroxide Before the start of the titration,

  any residual zinc oxide present is removed by centrifugal

  It is found that the conversion is almost

  calculated in relation to the initial concentration

  of dithiophosphoric acid used.

  Comparative Example (A) The experiment described in Example 1 is repeated, except that no quaternary ammonium compound is added after 10 minutes, the conversion determined by titration is not yet 50%. %; after 30 minutes, the conversion, calculated with respect to the initial concentration of the dithiophosphoric acid used, is not greater than 67%.

Example 2

  The experiment described in Example 1 is repeated, except that 0.11 g (0. 4 mmol) of tetrabutylammonium chloride is used. The conversion after 20 minutes, determined by titration, is almost quantitative, calculated by relation to the initial concentration of the acid

dithiophosphoric used.

Example 3

  The experiment described in Example 1 is repeated, with the difference that 0.17 g (0.42 mmol) of trioctylmethylammonium chloride is used. The conversion after 10 minutes, determined by titration, is almost quantitative, calculated relative to at the initial concentration of the acid

dithiophosphoric used.

Example 4

  The experiment described in Example 1 is repeated, except that 0.046 g (0.42 mmol) of tetramethylammonium chloride is used. The conversion after 10 minutes, determined by titration, is almost quantitative, calculated with respect to initial concentration of

  the dithiophosphoric acid used.

Example 5

  The experiment described in Example 1 is repeated, with the difference that 0.036 g (0.45 mmol) of ethylammonium chloride is used. The conversion after 10 minutes, determined by titration, is 94%, calculated relative to at the initial concentration of the dithiophosphoric acid used.

Example 6

  The experiment described in Example 1 is repeated, except that 0.039 g (0.27 mmol) of 1,2-diaminoethane dihydrochloride is used. The conversion after minutes, determined by titration, is 75%. calculated

  compared to the initial concentration of dithio-

phosphoric used.

Example 7

  The experiment described in Example 3 is repeated with a diisodecylthiophosphoric acid having a different quality, using a very small amount of trioctylmethylammonium chloride, ie one eighth of the amount mentioned in Example 3 After no more than 5 minutes , we determine the conversion (by titration) We find that it is 87%, calculated in relation to the

  initial concentration of dithiophosphoric acid.

  Comparative Example (B) The experiment described in Example 7 is repeated except that no quaternary ammonium compound is used. The conversion after 5 minutes, determined by titration, is not greater than 10 %, calculated by

  in relation to the initial concentration of dithio-

phosphoric used.

-13-

Claims (11)

  1 Process for the preparation of acid salts   dithiophosphoric compounds by neutralization of dithio   phosphoric compounds using basic reaction metal compounds, characterized in that the neutralization is carried out in the presence of one or more quaternary ammonium compounds comprising the group R R R R N O, 1 2 3 4   in which R 1, R, R 3 and R may be the same or different and represent a hydrogen atom or a substituted or unsubstituted alkyl, aryl, alkaryl or aralkyl group, with the proviso that at least one of they are not not a hydrogen atom.   Process according to Claim 1, characterized in   that the starting material is a dithiophosphoric acid with the general formula: R O S P SH R -O RB _ 0 /   wherein RA and RB may be the same or different and each represents an alkyl, cycloalkyl, aryl, alkaryl or aralkyl group having 2 to 20 carbon atoms, particularly a dithiophosphoric acid in which R and R are identical.   Process according to claim 1, characterized in that the starting material is a dithiophosphoric acid having the general formula: R O (C 2 H 4 O) (C 3 H 6 O) ys 24 x 36 Y P SH R O (C 2 H 4 O) p (C 3 H 6 O) q /   in which R and R have the meaning described above.   and p, q x and y are integers between 0 and 10, the sum of p, q, x and y being at least I.   4 Method according to one of the preceding claims,   characterized in that metal compounds of groups IIA and IIB of the periodic table of elements, in particular compounds of zinc, cadmium, magnesium, strontium or barium, are used, preferably composed of zinc.   Method according to one of the preceding claims,   characterized by using halides, nitrates,   quaternary ammonium sulphates or perchlorates, in particular   chlorides or quaternary ammonium bromides.   Process according to Claim 5, characterized in that quaternary ammonium compounds having at least four and preferably eight carbon atoms or more in the molecule.   Process according to Claim 6, characterized in that tetramethylammonium chloride,   tetramethylammonium bromide, nonyl chloride   ammonium chloride, tetrabutylammonium chloride, bromide   tetrabutylammonium or octyltrimethylammonium chloride.   Method according to one of the preceding claims,   characterized in that the amount of quaternary ammonium used is between 0.01% by weight and 10% by weight, preferably between 0.1% by weight and 5% by weight, by   compared to the dithiophosphoric acid used.   Method according to one of the preceding claims,   characterized in that the neutralization is carried out in the presence of a lubricating oil or a hydrocarbon as diluent.   Process for the preparation of lubricating compositions   compounds, characterized in that they comprise one or more dithiophosphoric acid salts prepared by neutralization of dithiophosphoric acids using basic reaction metal compounds in the presence of one or more quaternary ammonium compounds comprising 1 E34 E 1 2 The group RRRRN -, wherein R, R, R and R may be the same or different and represent a hydrogen atom or a substituted or unsubstituted alkyl, aryl, alkaryl or aralkyl group, with the proviso that at least   one of them is not a hydrogen atom.   Process according to claim 10, characterized in that the lubricating compositions comprise one or   several salts prepared by neutralization of dithio-   phosphoric compounds of formula (3) or (4), wherein R and R, p, q, x and y have the meaning described above, using basic reaction metal compounds, in particular zinc compounds, in the presence one or more quaternary ammonium compounds comprising the group RRR RN-, wherein R, R, R and R are meaning described above.   Lubricating compositions, characterized in that, in addition to a major amount of a lubricating oil, they comprise a minor amount of one or more dithiophosphoric acid salts obtained by neutralization of dithiophosphoric acids of formulas (3) or (4), wherein R and R, p1, x and y have the meaning described above, using basic reaction metal compounds, preferably zinc compounds, in the presence of one or more quaternary ammonium compounds. 1234 * D i 2 3 comprising the group RRRR N-, wherein R, R, R   and R 4 have the meaning described above.