AU610700B2

AU610700B2 - Copolymers of acrylic and/or methacrylic acid esters as flow improvers

Info

Publication number: AU610700B2
Application number: AU31024/89A
Authority: AU
Inventors: Claus-Peter Dr. Herold; Oliver Pietsch; Wolfgang Dr. Ritter; Stephan Dr. Von Tapavicza; Wolfgang Zollner
Original assignee: Henkel AG and Co KGaA
Current assignee: BASF Personal Care and Nutrition GmbH
Priority date: 1988-03-07
Filing date: 1989-03-06
Publication date: 1991-05-23
Anticipated expiration: 2009-03-06
Also published as: DK110689A; MX172301B; CA1334013C; DE3807394A1; EP0332000A2; EP0332000B1; NO890937D0; BR8901035A; JPH01290892A; TR23834A; AR247930A1; NO177470B; AU3102489A; EP0332000A3; DK110689D0; DE58909795D1; NO890937L; NO177470C

Description

I

S F Ref: 77899 FORM COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 0 7 0 0 COMPLETE SPECIFICATION I

(ORIGINAL)

FOR OFFICE USE: Class Int Class Complete Specification Lodged: Accepted: Published: S Priority: Related Art: Name and Address of Applicant: Henkel Kommanditgesellschaft auf Aktien Henkelstrasse 67 4000 Dusseldorf FEDERAL REPUBLIC OF GERMANY Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia i b i c-~ Address for Service: Complete Specification for the invention entitled: Copolymers of Acrylic and/or Methacrylic Acid Esters as Flow Improvers The following statement is a full description best method of performing it known to me/us of this invention, including the 5845/3 0 Vd 1 i- _j 5845/2 -1 Abstract The use is disclosed of copolymers of acrylic and/or methacrylic acid esters of higher alcohols or alcohol cuts with at least 16 C-atoms in the alcohol radical and not more than 5 by weight, preferably 0.5 to by weight, of maleic anhydride as flow improvers in paraffin-rich crude oils and/or mineral oil fractions with characteristic pour-points of above 25 0 C, to reduce their pour-points to values below 150C, preferably under 10 0

C.

0110 E 6 6

C

0

C

0 C C 00 C 44 00 0 0D 0 0 0$L Dusseldorf, 02.03.88 HENKEL KGaA TFP/Patentabteilung Patent Application D 8142 Use of selected copolymer types of acrylic and/or methacrylic acid esters as flow improvers in paraffin-rich mineral oils and mineral oil fractions (I) It is known that the flow properties of crude oils and/or mineral oil fractions can be improved by using limited quantities of synthetic flow aids with them. As is known, the purpose of these flow aids is the reduction of the actual temperature below which solid components in the fluid hydrocarbon mixture particularly higher paraffins, in some cases in combination with asphaltenes or other difficultly soluble components crystallize out in such quantities that the ability of the hydrocarbon mixture to flow is permanently impaired. The temperature range discussed here is measured by the known methods for measuring the pour-point or solidifying point. Every crude oil, or the mineral oil 0 o fractions obtained from it, has by reason of its specific composition its own characteristic pour-point, which however in many crude oils lies so low that no disadvantageous effect occurs during extraction and pipe-line transport. There are also however a whole series of mineral oil grades with a solidifying point above 10 0 C. Here already the use of flow aids based on different synthetic homo-polymer and/or copolymer types may be advisable in practice.

There is an extensive prior art in these aids, which are also described as paraffin inhibitors and are as a rule produced by the polymerization of olefin unsaturated compounds which contain at least partly unbranched, saturated hydrocarbon chains with at least 18 carbon atoms.

See, for example, in DE-AS 22 10 431 and the German Offenlegungsschrifte 26 12 757, 22 64 328, 20 62 023, 23 30 232, 19 42 504 and 20 47 448.

K 1 1 1 1 1 1 1 1 -2- C C P p po P P p C Pe C

PP-

00 0 00s 0 00b 00 0( In practice particular difficulties arise when the characteristic pourpoint of the crude oil or the mineral oil fractions to be treated reaches extremely high values, which in particular can come to at least 0 C and even to 30 0 C and over. Mineral oil substances of this type have a tendency towards rapid solidification even at ambient temperature. If, for example, pumping operations are interrupted even for only a short time or temperature regions with low temperatures are crossed in transport e.g. by pipes in sea water regions then the rapid solidification occurs of the hydrocarbon material into a mass which can no longer be pumped and with it the blocking of pipes, pumps and the like. The matter is made more difficult in that for ensured exclusion of disturbances of the type described, it is often required in practice to lower the pour-points of the oils or oil fractions below 0 C and particularly to values below 12 0 C or even below 10 0 C. It is immediately clear that technological difficulties of a quite particular nature arise when for example it is required that a characteristic pour-point of a crude oil of approx. 33 0 C should drop to values clearly below 10 0 C. As an additional difficulty it should also be considered here that the simple increase of the amount added of any chosen pourpoint improver does not in general result in a correspondingly increased lowering of the pour-point. Interactions, not explained in detail, between the flow aids and the solidifying constituents of the crude oil are probably responsible for a type of threshold effect for the intended aim, whereby the particular constitution of the flow aid has a decisive effect on its efficiency.

In DE-PS 30 31 900 mixed polymerizates are disclosed of n-alkylacrylates with at least 16 carbon atoms in the alcohol radical and maleic acid anhydride with molar ratios of n-alkyl acrylate to maleic acid anhydride of 20 1 to 1 10. Compounds of this type are to be used as cristallization inhibitors for crude oils containing paraffins.

Numbered examples relate to the use of corresponding copolymers in the molar ratio of acrylic acid ester to maleic acid anhydride between 1 1 and 8 1. Crude oils are predominantly used with characteristic solidifying points of below 20 0 C. A table of values is concerned with 'the India crude oil which is known to be a particularly high-paraffin starting material (disturbing paraffin content 15%) and has a characteristic solidifying point of 33 0 C. The optimum efficiency of 3the mixed polymerizate used in this publication as regards the lowering of the solidifying point of this starting material lies at the molar ratio of acrylic acid ester/maleic acid anhydride of 4:1. The lowest solidifying points set here lie at 120C. If the maleic acid anhydride proportion in the copolymerizate is reduced further then with the addition of identical amounts the solidifying points of the India crude oil mixed with it rise again (cf. for this particularly Table 2 of the literature cited).

The teaching of the present invention arises accordingly from the surprising knowledge that a particularly effective reduction of the solidifying temperatures determined according to the known methods of pour-point and/or solidifying point measurement can be obtained Co effectively with starting materials with high paraffin contents and C_ I therefore particularly high characteristic solidifying temperatures, if the C copolymer types of the kind last described are used as flow aids which are 4C15 distinguished by an extremely low content of maleic acid anhydride. It has o proved surprisingly to be the case that selected copolymerizates with C: C extremely low maleic acid anhydride contents can be particularly suitable, C C effectively to reduce directly the limiting temperatures of the flowability of crude oils or the corresponding mineral oil fractions high in paraffin.

According to a first embodiment of the present invention there is provided a method of reducing the pour-point value and for improving, I 9: flowability of paraffin-rich crude oils and/or mineral oil fractions with characteristic pour-points above 250C to below 150C, by adding a copolymer thereto: wherein the copolymer is comprised of acrylic and/or methacrylic acid esters of alcohol cuts with at least 16 carbon atoms in the alcohol radical and not more than 5% by weight of maleic acid anhydride based on the copolymer weight.

0 s The subject of the invention is accordingly the use of copolymers of acrylic and/or methacrylic acid esters of higher alcohols or alcohol cuts r 30 with at least 16 carbon atoms in the alcohol radical and not more than by weight maleic acid anhydride by weight referred to copolymer weight as flow improvers in paraffin-rich crude oils and/or mineral oil fractions with characteristic pour-points above 200C and particularly above Particularly suitable for the method according to the invention are copolymers of the named type, with a maleic acid anhydride content in the range of approximately. 0.5 to 2.5% by weight and particularly in the range of approximately 1 to 2% by weight. The figures for by weight also refer A 9 o 0 Acoringto afirt ebodmentof he resnt ivenionthee i X m I_ 3A here to the amount of total monomer. It is part of the teaching according to the invention to adjust the pour-points of the crude oils and/or mineral oil fractions used which have starting or characteristic pour-points above and particularly above 30°C, by the addition of the flow improvers defined f C C C CC C C t 0 o T 4t 0 211 o0 0 0

I

-4according to the invention to values below 15 0 C and preferably under 0 C. According to the invention it is for example possible by adding conventional quantities of the pour-point improvers in the sense of invention to obtain pour-points of the extremely paraffin-rich starting materials in the range of approx. 0 to 8 0 C. With this the problem-free handling of these crude oils or oil fractions under normal everyday conditions is also ensured. In particular it is ensured that pipes, distributors and the like which are under water can be operated without problems.

Particularly suitable for the teaching of the invention are copolymers containing small quantities of maleic acid anhydride, based on the esters of acrylic acid. The further particularly preferred acrylic ot(t acid esters contain comparatively long-chain alcohol radicals, which can be at least predominantly n-alkyl radicals and have preferred chain lengths in the range of C 1 8 to C 24 Alcohols with a higher carbon number, particularly up to around C 30 and/or alcohols with a lower carbon number to around C 1 6 can also be used as constituents. In r, particular the solubility of the copolymerizate in common solvents, for example, toluol and the like, is benefited by the use of corresponding alcohol cuts in the production of the acrylic acid esters and their subsequent copolymerization with maleic acid anhydride.

It has emerged furthermore that when only small amounts of maleic acid anhydride are used in the pour-point improvers as co-monomers in the sense of the invention teaching then particularly effective copolymers are obtained if comparatively high contents of alcohol radicals with at least 22 C-atoms are present in the acrylate or methacrylate components. It can therefore be useful in the sense of the invention to use alcohol cuts for the production of the acrylate component(s), with a content of C 22 alcohol of at least around 35 by weight and particularly 'at least around 45 by weight. Particularly good pourpoint improvers are then obtained if these long-chain alcohol components in the alcohol cuts used for the production of the (meth)acrylate components are over 50 by weight. The by weight figures given here refer to the content of C 22 -alcohol and, i.f present, higher alcohols in the alcohol mixture which has been used for the production of the acrylate or methacrylate components.

The application concentration of the pour-point improvers according to the invention lies in the conventional range and amounts, for example, to 20 to 1000 ppm, whereby quantities in the range of 100 to 500 ppm are preferred. The pour-point improvers are thereby conveniently used in suitable solvents. Details on this matter and on the production of the copolymerizate are to be found in the related prior art, for example in the already cited DE-PS 30 31 900.

The alcohols or alcohol cuts used for the production of the acrylate components can be of natural or synthetic origin. Alcohol cuts with a preponderant proportion of components with at least 22 C-atoms, but at the same time lower quantities of alcohol components in the range C 16 Sto C 2 0 are the preferred materials to be used. In a particular S. embodiment of the invention acrylates or methacrylates selected in this way with maleic acid anhydride are copolymerized in such mixture ratios, that. the molar ratio of alkyl-acrylate or methacrylate to 0t' maleic acid anhydride is greater than 20 1.

0 Examples a For the production of the maleic acid anhydride copolymerizate the two °0 0 acrylate ester mixtures A and B are used which differ in the chain distribution of the fatty alcohol mixture used in each case for acrylic acid esterification. The two acrylate types are characterized as follows: o" Table 1 C-chain distribution of the fatty alcohol/%

C

16

C

18

C

20

C

22 Acrylate A 16.3 22.9 10.7 46.9 Acrylate B 1.5 8.6 15.2 68.8 For the production of the acrylate/MAH-copolymers two process types are used, the batch-process and the in-flow process.

-6flask.

The charge is evacuated for 10 x 1 minutes with a stirrer rotation rate of 70 rpm and the vacuum is each time released with 99.999 nitrogen.

At a stirrer rotation rate of 50 rpm and with light N 2 flow the charge is heated to 90 0 C and held at this temperature. The operation is carried out under inert conditions for the whole reaction. The Scomnencement of the reaction is indicated by a teierature increase of 93 to 96 0 C. The charge is kept for 3 h at 90 0 C 1 0 C. After this time it is cooled within 45 min to ambient temperature and the product is drawn off.

Here and in the in-flow process below, toluol is used as the solvent.

S0 S* The polyme ization initiator used is dibenzoylperoxide or o oo 00 0 The monomers are dissolved in toluol in the mixture ratio desired at o drawn off.

that the total addition timure i (parts 2.5by weight).h.

Hperimental execution of the in-flow process: the time at 45 to 50 0 C and the solution is then cooled to 25 0 C. The initiator is also dissolved in toluol. Approx. 20% of the onomer solution measured per batch is placed in a reactor. The reactor is rinsed three times with nitrogen and heated to 90 0 C with light N 2 flow with stirring. The initiator solution is now added in such quantities that the total addition time is 2.5 h. 1 o o o

H

S -7- Approx. 20 min after the beginning of the addition of the initiator a temperature increase occurs. The temperature is held at 90 3 0 C by cooling the reactor jacket.

minutes after the beginning of the addition of the initiator the remaining monomer solution is added in doses to the reactor in such a way that the total addition time comes to 2 h. During the entire reaction time the temperature is held at 90 3 0 C. Following this the reaction rmiture is held for a further 60 min at the same temperature.

e then the reaction product is cooled and drawn off at 30 0

C.

0 a o 8 o 0 In the following Table 2 the Examples 1 to 10, according to the invention, are summarized. It shows the type of acrylate monomer A or B used for the respective Example and the percentage content by weight) of the maleic acid anhydride in the monomer mixture for the 900 0° production of the pour-point reducer. In the Examples 1 and 2 the flow 0 00 0 0C a 0 0 improver has been produced according to the batch process and in the S Examples 3 to 10 according to the in-flow process.

As the initiator azoisobutyronitrile is used in the Examples 1 to 7 and in all the other examples dibenzoylperoxide is used.

Table 2 finally shows the specific viscosity of the respectively produced copolymer solutions. The viscosity measurement is carried out here using a Ubbelohde-viscometer, capillary I, 0 0.63 mm. The toluol 4 solutions measured are here 3 solutions in toluol. The measurement is carried out at 20 0 C after a temperature equalization of 10 min.

I 1 r 8 Table 2 finally contains the pour-point values, which have been obtained with the addition of the pour-point improver to an India-Crude (Bombay Crude oil) according to the following process.

Determination of the pour-point The pour-point was determined as follows, according to ASTM D 97-66 or DIN 51597 25.0 g of Bombay Crude oil was held with 800 ppm of the 50 by weight solution of the flow improver in a closed vessel for 15 min at 50 0 C and "wo then shaken strongly 5 times at regular intervals. The crude oil thus doped was quickly decanted into a cylindrical glass vessel with an oayo inside diameter of 27 mm and this inmediately closed vessel hung at a sufficient depth in a water bath at 36 0

C.

After 30 min the glass was tilted slightly to the side and it was a S observed whether the contents were fluid. The sample was then cooled in stages of 3 0 C and the test procedure carried out each time. At the o> 090 temperature at which the contents no longer flowed even when the test glass was tilted to 900, 30 was added and this temperature taken as the pour-point.

The pour-point of the untreated Bombay-crude oil according to this method of determination is 30 0

C.

I' i I -9- Table 2 Ex. Acrylate %by weight MAHl in specific pour-point in type copolymers viscosity Boxtbay-crude oil (OC) 1 A 1.25 0.657 6 2 A 5 1.17 9 3 A 0.25 0.56 12 4 A 0.5 0.65 12-15 A 1.25 0.65 6 &6 B 1.25 0.64 3 7 A 1.25 0.37 9 *bo8 A 2.5 0.83 9 9 A 2.5 0.61 9 S 10 B 5 0.52 12 dp' 0 Af I

Claims

1. A method of reducing the pour-point value and for improving, flowability of paraffin-rich crude oils and/or mineral oil fractions with characteristic pour-points above 25°C to below 15°C, by adding a copolymer thereto: wherein the copolymer is comprised of acrylic and/or methacrylic acid esters of alcohol cuts with at least 16 carbon atoms in the alcohol radical and not more than 5% by weight of maleic acid anhydride based on the copolymer weight.

2. A method according to claim 1, wherein the pour-points values are reduced below

3. A method according to claims 1 or 2, wherein the paraffin-rich crude oils and/or mineral oil fractions have characteristic pour-points of at least 30 0 C.

4. A method according to any one of claims 1 to 3, wherein the esters are based on alcohol cuts having 18 to 24 carbon atoms.

A method according to claim 4, wherein the alcohol cuts contain at least about 35% by weight of alcohols containing 22 carbon atoms.

6. A method according-to claim 4, wherein the alcohol cuts contain at least about 45% by weight of alcohols containing 22 carbon atoms.

7. A method according to any one of claims 1 to 6, wherein the copolymer contains 0.5 to 2.5% by weight of maleic acid anhydride.

8. A method according to any one of claims 1 to 6, wherein the copolymer contains 1 to 2% by weight of maleic acid anhydride.

9. A method of reducing the pour-point value of paraffin-rich crude oils and/or mineral oil fractions with characteristic pour-points above to below 15°C substantially as hereinbefore described with reference to any one of the Examples. o

10. Paraffin-rich crude oils and/or mineral oil fractions when a 0 modified by the method of any one of claims 1 to 9. DATED this TWENTY-FOURTH day of JANUARY 1991 Henkel Kommanditgesellschaft auf.Aktien Patent Attorneys for the Applicant SPRUSON FERGUSON 7 o$1421R