Process for producing nitrile rubbers using ruthenium complex catalysts

Abstract

The present invention relates to a process for preparing nitrile rubbers having reduced molecular weight by metathesis of a first nitrile rubber in the presence of specific ruthenium complex catalysts that have particular N-heterocyclic carbene ligands.

Claims

1. A process for reducing the molecular weight of nitrile rubber, said process comprising conducting a metathesis reaction of a reaction mixture comprising the nitrile rubber, optionally in the presence of a co-olefin, and in the presence of a ruthenium complex catalyst selected from the group consisting of: ##STR00036##

2. Process for reducing the molecular weight of nitrile rubber according to claim 1, wherein the amount of catalyst used is 5 to 1000 ppm of precious metal, based on the nitrile rubber used.

3. Process for reducing the molecular weight of nitrile rubber according to claim 1, which is conducted in the presence of a co-olefin.

4. Process for reducing the molecular weight of nitrile rubber according to claim 1, wherein the concentration of the nitrile rubber in the reaction mixture is in the range from 1% by weight to 30% by weight, based on a weight of the reaction mixture.

5. Process for reducing the molecular weight of nitrile rubber according to claim 1, which is conducted at a temperature in the range from 10° C. to 150° C.

6. Process for reducing the molecular weight of nitrile rubber according to claim 1, wherein one or more further copolymerizable monomers are used.

7. Process for reducing the molecular weight of nitrile rubber according to claim 1, in which the metathesis reaction of the nitrile rubber is followed by a hydrogenation reaction of the unsaturated C═C double bonds in the nitrile rubber.

Description

EXAMPLES

I Description of the Analysis Methods

(1) Gel Permeation Chromatography (GPC) Procedure:

(2) The molecular weight M.sub.n and M.sub.w is calculated by means of the Waters Empower 2 Data Base Software, and determined using the following equipment: A Shimadzu LC-20AT high performance liquid chromatography (HPLC) pump, an SFD S5200 autosampler, 3 PLgel 10 μm Mixed-B columns (300×7.5 mm ID), a Shodex RI-71 detector, an ERC column oven. The GPC experiments were conducted at 40° C. and a flow rate of 1 ml/min with tetrahydrofuran (THF) as eluent. The GPC column was calibrated with standard polystyrene (PS) samples.

(3) Determination of the Residual Double Bond (“RDB”) Content:

(4) The RDB in % is determined by means of the following FT-IR method: The spectrum of the nitrile rubber is recorded before, during and after the hydrogenation reaction by means of a Thermo Nicolet FT-IR spectrometer of the AVATAR 360 type. The NBR solution in monochlorobenzene was applied to an NaCl disc and dried in order to obtain a film for the analysis. The hydrogenation rate is determined by means of the FT-IR analysis according to ASTM Standard D 5670-95.

(5) Determination of Mooney Viscosity:

(6) The determination of the Mooney viscosity is determined by the method of ASTM Standard D 1646. The Mooney viscosity ML 1+4 @ 100° C. was measured at 100° C. with a preheating time of one minute and measurement time of 4 minutes.

(7) Determination of Brookfield Viscosity:

(8) The solution viscosity of a polymer solution in MCB is determined with a Brookfield LV DV II+ rotary viscometer. The measurements were conducted with a 62 standard spindle in a 400 ml beaker filled with 250 ml of polymer solution at a temperature of 23±0.1° C.

II Materials Used

(9) Table 1 summarizes the non-inventive catalysts used in the examples described hereinafter (Grubbs II, Grubbs-Hoveyda II, Zhan 1B, M71 SIMes and M73 SIMes).

(10) Table 2 summarizes the inventive catalysts used in the examples described hereinafter (M71 SIPr, M73 SIPr, M74 SIPr).

(11) TABLE-US-00001 TABLE 1 Non-inventive catalysts used Catalyst Molecular weight name Structural formula [g/mol] Source Grubbs II catalyst (G II) 848.33 Materia/Pasadena; USA Grubbs- Hoveyda II catalyst (GH II) 626.14 Aldrich Zhan 1B 733.75 Strem Chemicals M71 SIMes 0 737.64 Umicore M73 SIMes 741.75 Umicore

(12) TABLE-US-00002 TABLE 2 Inventive catalysts used Catalyst Molecular weight name Structural formula [g/mol] Source M71 SIPr 821.80 Umicore M73 SIPr 825.91 Umicore M74 SIPr 825.87 Umicore
Legend:

(13) Ph in each case represents a phenyl radical.

(14) Dipp in each case represents a diisopropylphenyl radical.

(15) Mes in each case represents a 2,4,6-trimethylphenyl radical.

(16) ##STR00035##
Nitrile Rubbers Used

(17) The examples described hereinafter were conducted using different NBR and HNBR grades from ARLANXEO Deutschland GmbH. These nitrile rubbers had the characteristic indices shown in Table 3.

(18) TABLE-US-00003 TABLE 3 Nitrile rubbers used Acrylo nitrile- Mooney content value Molecular Molecular (ACN) (ML 1 + 4 weight weight Nitrile [% by @ 100° C.) M.sub.w M.sub.n rubber wt.] [MU] [kg/mol] [kg/mol] PDI RDB NBR-1 34 30 250 75 3.4 100 NBR-2 34 30 252 75 3.4 100 NBR-3 34 30 273 75 3.7 100 NBR-4 34 30 251 74 3.4 100 NBR-5 34 30 240 71 3.4 100 NBR-6 34 30 266 73 3.6 100 NBR-7 34 35 263 75 3.5 100 NBR-8 34 30 — — — 100 HNBR 34 68 283 83 3.4 5.5 PDI = M.sub.w/M.sub.n; MU = Mooney units

(19) TABLE-US-00004 TABLE 4 Additions used Molecular Structural weight Addition formula [g/mol] Source Lithium bromide LiBr 86.85 Aldrich Lithium chloride LiCl 42.39 Fluka Magnesium MgCl.sub.2 95.21 Fluka chloride Calcium chloride CaCl.sub.2 110.98 Aldrich Triisopropyl (OiPr).sub.3B 188.07 Aldrich borate Titanium Ti(OiPr).sub.4 284.22 Aldrich isopropoxide

III Metathesis Reactions

(20) Table 5 gives an overview of the inventive examples and the corresponding non-inventive reference examples, the inventive examples being identified by “*”.

(21) In Examples 1a to 8b* and 12* to 17*, the nitrile rubber degradation was conducted in the form of a cross-metathesis with additions of 1-hexene. Both in the inventive examples and in the corresponding reference examples, the catalysts were used in such amounts as to result in ruthenium inputs of 9 ppm and 18 ppm in each case.

(22) In Examples 9, 10* and 11, the nitrile rubber degradation was conducted in the form of a self-metathesis without additions of 1-hexene. These examples were conducted with ruthenium inputs of 67 ppm.

(23) In Examples 17* and 18, the metathesis of partly hydrogenated nitrile rubber was conducted. The metathesis was conducted without additions of 1-olefin (self-metathesis) with ruthenium inputs of 151 ppm and at 100° C.

(24) TABLE-US-00005 TABLE 5 Overview of the experiments conducted (* = inventive experiments) Catalyst Addition Amount Mn Mw NBR Amount Ru Amount of 1-hexene T (24 h) (24 h) No. type Type [mmol] [ppm] Type [phr] [phr] [° C.] [kg/mol] [kg/mol] 1a NBR-1 G II 0.0066 9 — — 4 22 59 161 1b NBR-1 G II 0.0133 18 — — 4 22 48 116 2a NBR-2 GH II 0.0066 9 — — 4 22 54 145 2b NBR-2 GH II 0.0133 18 — — 4 22 45 107 3a NBR-2 Zhan 0.0066 9 — — 4 22 54 157 1B 3b NBR-2 Zhan 0.0133 18 — — 4 22 45 106 1B 4a NBR-3 M71 0.0066 9 — — 4 22 62 187 SIMes 4b NBR-3 M71 0.0133 18 — — 4 22 50 135 SIMes 5a* NBR-4 M71 0.0067 9 — — 4 22 42 99 SIPr 5b* NBR-4 M71 0.0134 18 — — 4 22 28 62 SIPr 6a NBR-5 M73 0.0066 9 — — 4 22 56 157 SIMes 6b NBR-5 M73 0.0132 18 — — 4 22 43 101 SIMes 7a* NBR-5 M73 0.0066 9 — — 4 22 41 95 SIPr 7b* NBR-5 M73 0.0132 18 — — 4 22 27 56 SIPr 8a* NBR-4 M74 0.0067 9 — — 4 22 43 106 SIPr 8b* NBR-4 M74 0.0133 18 — — 4 22 30 61 SIPr  9 NBR-6 M73 0.0500 67 — — 0 22 60 164 SIMes 10* NBR-6 M73 0.0500 67 — — 0 22 52 124 SIPr 11 NBR-6 GH II 0.0500 67 — — 0 22 56 145 12* NBR-3 M71 0.0066 9 LiBr 1.8 4 22 23 50 SIPr 13* NBR-3 M73 0.0066 9 Ti(O 0.039 4 22 35 81 SIPr iPr).sub.4 14* NBR-3 M73 0.0132 18 Mg 0.65 4 22 23 49 SIPr Cl.sub.2 15 * NBR-3 M71 0.0066 9 CaC 0.5 4 22 32 68 SIPr I.sub.2 16* NBR-3 M73 0.0132 18 LiCl 0.65 4 22 10 22 SIPr 17* HNBR M73 0.0750 151 — — 0 100 71 186 SIPr 18 HNBR GH II 0.0750 151 — — 0 100 73 195 G II = Grubbs II catalyst; GH II = Grubbs-Hoveyda II catalyst;
Procedure for the Metathesis Reactions

(25) All metathesis reactions were conducted in solution using monochlorobenzene (from Aldrich), called “MCB” hereinafter. Prior to use, the MCB was distilled and inertized by passing nitrogen through it at room temperature. The amounts of nitrile rubber noted in the tables which follow were dissolved in MCB at room temperature with agitation over a period of 12 hours. The additions (olefins) noted in the tables were added to the rubber-containing solution and stirred for 2 hours for homogenization. For experiments with additions, the additions were added at this point and the rubber-containing solution was stirred for another 1 hour. Prior to the addition of catalyst, the rubber solutions in monochlorobenzene were heated to the temperatures noted in the tables. Reaction mixtures 1 to 11 were designed such that the rubber concentration after addition of catalyst was 15% by weight; reaction mixtures 12 and 13 were designed such that the rubber concentration after addition of catalyst was 10% by weight.

(26) The metathesis catalysts (see Table 1) were each dissolved in 1 ml (0.0066 mmol of catalyst) or 2 ml (0.013 mM of catalyst) of MCB and added immediately to the nitrile rubber solutions. The addition of catalyst started the metathesis reactions, and they were monitored at regular time intervals (1 hour, 3 hours, 24 hours) by measuring the average molecular weight by means of gel permeation chromatography. The samples (5 ml each time) taken to determine the molecular weight were immediately stopped by addition of 0.8 ml of ethyl vinyl ether. The viscosities of the end samples (after a reaction time of 24 hours) were also determined in solution with the aid of a Brookfield viscometer (measurement temperature: 21° C.).

Inventive Examples and Comparative Examples

Examples 1a and b: Reaction of NBR with Grubbs II Catalyst

(27) TABLE-US-00006 Rubber ACN ML1 + 4 content (100° C.) Amount Name [% by wt.] [MU] [g] NBR-1 34 30 75.15

(28) TABLE-US-00007 Reaction conditions Catalyst Ru based on Co-olefin Temp- Amount Amount NBR Amount erature No. Type [mg] [mmol] [ppm] Type [phr] [° C.] 1a Grubbs 5.6 0.0066 9 1-hexene 4 22 1b II 11.2 0.0133 18 1-hexene 4 22

(29) TABLE-US-00008 Example 1a Example 1b Reaction time [h] Reaction time [h] Analytical data 0 1 3 24 0 1 3 24 M.sub.w [kg/mol] 250 174 161 161 252 133 116 116 M.sub.n [kg/mol] 75 62 59 59 75 53 48 48 PDI 3.4 2.8 2.7 2.8 3.4 2.5 2.4 2.4 Viscosity [mPa*s] 2434 — — 603 2434 — — 271 Viscosity/M.sub.w 0.0101 — — 0.0044 0.0101 — — 0.0030 [Pa*s*mol/kg]

Examples 2a and b: Reaction of NBR with Grubbs-Hoveyda II Catalyst

(30) TABLE-US-00009 Rubber ACN ML1 + 4 content (100° C.) Amount Name [% by wt.] [MU] [g] NBR-2 34 30 75.05

(31) TABLE-US-00010 Reaction conditions Catalyst Ru based on Co-olefin Temp- Amount Amount NBR Amount erature No. Type [mg] [mmol] [ppm] Type [phr] [° C.] 2a Grubbs-  5.9 0.0066  9 1-hexene 4 22 2b Hoveyda II 11.7 0.0133 18 1-hexene 4 22

(32) TABLE-US-00011 Example 2a Example 2b Reaction time [h] Reaction time [h] Analytical data 0 1 3 24 0 1 3 24 M.sub.w [kg/mol] 252 145 145 145 252 107 107 107 M.sub.n [kg/mol] 75 55 55 54 75 45 45 45 PDI 3.4 2.6 2.7 2.7 3.4 2.4 2.4 2.4 Viscosity 2774 — — 623 2774 — — 293 [mPa*s] Viscosity/M.sub.w 0.0110 — — 0.0043 0.0110 — — 0.0027 [Pa*s*mol/kg]

Examples 3a and b: Reaction of NBR with Zhan 1B Catalyst

(33) TABLE-US-00012 Rubber ACN ML1 + 4 content (100° C.) Amount Name [% by wt.] [MU] [g] NBR-2 34 30 75.05

(34) TABLE-US-00013 Reaction conditions Catalyst Ru based on Co-olefin Amount Amount NBR Amount No. Type [mg] [mmol] [ppm] Type [phr] [° C.] 3a Zhan 4.9 0.0066  9 1-hexene 4 22 3b 1B 9.7 0.0133 18 1-hexene 4 22

(35) TABLE-US-00014 Example 3a Example 3b Reaction time [h] Reaction time [h] Analytical data 0 1 3 24 0 1 3 24 M.sub.w [kg/mol] 252 156 156 157 252 106 106 106 M.sub.n [kg/mol] 75 54 55 54 75 44 44 45 PDI 3.4 2.9 2.8 2.9 3.4 2.4 2.4 2.3 Viscosity 2774 − − 697 2774 − − 282 [mPa*s] Viscosity/M.sub.w 0.0110 − − 0.0044 0.0110 − − 0.0027 [Pa*s*mol/kg]

Examples 4a and b: Reaction of NBR with M71 SIMes Catalyst

(36) TABLE-US-00015 Rubber ACN ML1 + 4 content (100° C.) Amount Name [% by wt.] [MU] [g] NBR-3 34 30 75.00

(37) TABLE-US-00016 Reaction conditions Catalyst Ru based Tem- on Co-olefin per- Amount Amount NBR Amount ature No. Type [mg] [mmol] [ppm] Type [phr] [° C.] 4a M71 4.9 0.0066 9 1-hexene 4 22 4b SIMes 9.8 0.0133 18 1-hexene 4 22

(38) TABLE-US-00017 Example 4a Example 4b Reaction time [h] Reaction time [h] Analytical data 0 1 3 24 0 1 3 24 M.sub.w [kg/mol] 273 − − 187 273 − − 135 M.sub.n [kg/mol] 75 − − 62 75 − − 50 PDI 3.7 − − 3.0 3.7 − − 2.7 Viscosity [mPa*s] 2959 − − 907 2959 − − 409 Viscosity/M.sub.w 0.0108 − − 0.0049 0.0108 − − 0.0030 [Pa*s*mol/kg]

Examples 5a* and b*: Reaction of NBR with M71 SIPr Catalyst

(39) TABLE-US-00018 Rubber ACN ML1 + 4 content (100° C.) Amount Name [% by wt.] [MU] [g] NBR-4 34 30 75.00

(40) TABLE-US-00019 Reaction conditions Catalyst Ru based Tem- on Co-olefin per- Amount Amount NBR Amount ature No. Type [mg] [mmol] [ppm] Type [phr] [° C.] 5a* M71 5.5 0.0066 9 1-hexene 4 22 5b* SIPr 11.0 0.0133 18 1-hexene 4 22

(41) TABLE-US-00020 Example 5a Example 5b Reaction time [h] Reaction time [h] Analytical data 0 1 3 24 0 1 3 24 M.sub.w [kg/mol] 251 104 100 99 251 66 63 62 M.sub.n [kg/mol] 74 43 42 42 74 29 28 28 PDI 3.4 2.4 2.4 2.4 3.4 2.2 2.2 2.2 Viscosity [mPa*s] 2519 − − 215 2519 − − 83 Viscosity/M.sub.w 0.0100 − − 0.0022 0.0100 − − 0.0029 [Pa*s*mol/kg]

Examples 6a and b: Reaction of NBR with M73 SIMes Catalyst

(42) TABLE-US-00021 Rubber ACN ML1 + 4 content (100° C.) Amount Name [% by wt.] [MU] [g] NBR-5 34 30 75.05

(43) TABLE-US-00022 Reaction conditions Catalyst Ru based Tem- on Co-olefin per- Amount Amount NBR Amount ature No. Type [mg] [mmol] [ppm] Type [phr] [° C.] 6a M73 4.9 0.0066 9 1-hexene 4 22 6b SIMes 9.8 0.0132 18 1-hexene 4 22

(44) TABLE-US-00023 Example 6a Example 6b Analytical Reaction time [h] Reaction time [h] data 0 1 3 24 0 1 3 24 M.sub.w [kg/mol] 240 158 158 157 240 102 102 101 M.sub.n [kg/mol] 71 56 57 56 71 42 44 43 PDI 3.4 2.8 2.8 2.8 3.4 2.4 2.3 2.4 Viscosity [mPa*s] 2437 − − 681 2437 − − 224 Viscosity/M.sub.w 0.0102 − − 0.0043 0.0102 − − 0.0022 [Pa*s*mol/kg]

Examples 7a* and b*: Reaction of NBR with M73 SIPr Catalyst

(45) TABLE-US-00024 Rubber ACN ML1 + 4 content (100° C.) Amount Name [% by wt.] [MU] [g] NBR-5 34 30 75.05

(46) TABLE-US-00025 Reaction conditions Catalyst Ru based on Co-olefin Amount Amount NBR Amount Temperature No. Type [mg] [mmol] [ppm] Type [phr] [° C.] 7a* M73 5.5 0.0066 9 1-hexene 4 22 7b* SIPr 10.9 0.0132 18 1-hexene 4 22

(47) TABLE-US-00026 Example 7a Example 7b Analytical Reaction time [h] Reaction time [h] data 0 1 3 24 0 1 3 24 M.sub.w [kg/mol] 240 98 97 95 240 60 57 56 M.sub.n [kg/mol] 71 41 40 41 71 28 27 27 PDI 3.4 2.4 2.4 2.3 3.4 2.2 2.1 2.1 Viscosity [mPa*s] 2437 − − 190 2437 − − 63 Viscosity/M.sub.w 0.0103 − − 0.0020 0.0102 − − 0.0011 [Pa*s*mol/kg]

Examples 8a* and b*: Reaction of NBR with M74 SIPr Catalyst

(48) TABLE-US-00027 Rubber ACN ML1 + 4 content (100° C.) Amount Name [% by wt.] [MU] [g] NBR-4 34 30 75.00

(49) TABLE-US-00028 Reaction conditions Catalyst Ru based on Co-olefin Temper- Amount Amount NBR Amount ature No. Type [mg] [mmol] [ppm] Type [phr] [° C.] 8a* M74 5.5 0.0067 9 1-hexene 4 22 8b* SIPr 11.0 0.0133 18 1-hexene 4 22

(50) TABLE-US-00029 Example 8a Example 8b Reaction time [h] Reaction time [h] Analytical data 0 1 3 24 0 1 3 24 M.sub.w [kg/mol] 251 110 106 106 251 63 61 61 M.sub.n [kg/mol] 74 45 44 43 74 31 30 30 PDI 3.4 2.5 2.4 2.4 3.4 2.1 2.1 2.1 Viscosity 2519 — — 261 2519 — — 75 [mPa*s] Viscosity/M.sub.w 0.0100 — — 0.0025 0.0100 — — 0.0025 [Pa*s*mol/kg]

Example 9: Reaction of NBR with M73 SIMes Catalyst without Olefin

(51) TABLE-US-00030 Rubber ACN ML1 + 4 content (100° C.) Amount Name [% by wt.] [MU] [g] NBR-6 34 30 75.00

(52) TABLE-US-00031 Reaction conditions Catalyst Amount Amount Ru based on Temperature No. Type [mg] [mmol] NBR [ppm] [° C.] 9 M73 SIMes 37.1 0.0500 67 22

(53) TABLE-US-00032 Example 9 Reaction time [h] Analytical data 0 24 M.sub.w [kg/mol] 266 164 M.sub.n [kg/mol] 73 60 PDI 3.6 2.8 Viscosity [mPa*s] 2599 895 Viscosity/M.sub.w 0.0098 0.0062 [Pa*s*mol/kg]

Example 10*: Reaction of NBR with M73 SIPr Catalyst without Olefin

(54) TABLE-US-00033 Rubber ACN content ML1 + 4 (100° C.) Amount Name [% by wt.] [MU] [g] NBR-6 34 30 75.00

(55) TABLE-US-00034 Reaction conditions Catalyst Amount Amount Ru based on Temperature No. Type [mg] [mmol] NBR [ppm] [° C.] 10* M73 SIPr 41.3 0.0500 67 22

(56) TABLE-US-00035 Example 10 Reaction time [h] Analytical data 0 24 M.sub.w [kg/mol] 266 124 M.sub.n [kg/mol] 73 52 PDI 3.6 2.4 Viscosity [mPa*s] 2599 360 Viscosity/M.sub.w 0.0098 0.0029 [Pa*s*mol/kg]

Example 11: Reaction of NBR with Grubbs-Hoveyda II Catalyst without Olefin

(57) TABLE-US-00036 Rubber ACN content ML1 + 4 (100° C.) Amount Name [% by wt.] [MU] [g] NBR-6 34 30 75.00

(58) TABLE-US-00037 Reaction conditions Catalyst Amount Amount Ru based Temperature No. Type [mg] [mmol] on NBR [ppm] [° C.] 11 Grubbs-Hoveyda II 44.2 0.0500 67 22

(59) TABLE-US-00038 Example 11 Reaction time [h] Analytical data 0 24 M.sub.w [kg/mol] 266 145 M.sub.n [kg/mol] 73 56 PDI 3.6 2.6 Viscosity [mPa*s] 2599 662 Viscosity/M.sub.w 0.0098 0.0040 [Pa*s*mol/kg]

Examples 12*-16*: Reaction of NBR with M71 SIPr or M73 SIPr Catalyst and Additions in the Presence of Olefin

(60) TABLE-US-00039 Rubber ACN content ML1+ 4(100° C.) Amount Name [% by wt.] [MU] [g] NBR-3 34 30 75.00

(61) TABLE-US-00040 Catalyst Ru Reaction conditions based Co-olefin Addition Amount Amount on NBR Amount Amount Temp. No. Type [mg] [mmol] [ppm] Type [phr] Type [phr] [° C.] 12* M71 5.42 0.0066 9 1- 4 LiBr 1.8 22 SIPr hexene 13* M73 5.45 0.0066 9 1- 4 Ti(OiPr).sub.4 0.039 22 SIPr hexene 14* M73 10.9 0.0132 18 1- 4 MgCl.sub.2 0.65 22 SIPr hexene 15* M71 5.42 0.0066 9 1- 4 CaCl.sub.2 0.5 22 SIPr hexene 16* M73 10.9 0.0132 18 1- 4 LiC1 0.65 22 SIPr hexene

(62) TABLE-US-00041 Example 12 Example 13 Reaction time [h] Reaction time [h] Analytical data 0 1 3 24 0 1 3 24 M.sub.w [kg/mol] 273 59 51 50 273 84 82 81 M.sub.n [kg/mol] 75 25 23 23 75 37 34 35 PDI 3.7 2.3 2.2 2.1 3.7 2.3 2.4 2.3 Viscosity 2599 — — 46 2599 — — 126 [mPa*s] Viscosity/M.sub.w 0.0098 — — 0.0009 0.0098 — — 0.0016 [Pa*s*mol/kg]

(63) TABLE-US-00042 Example 12 Example 13 Reaction time [h] Reaction time [h] Analytical data 0 1 3 24 0 1 3 24 M.sub.w [kg/mol] 273 53 49 49 273 80 71 68 M.sub.n [kg/mol] 75 23 21 23 75 37 33 32 PDI 3.7 2.2 2.4 2.1 3.7 2.1 2.1 2.1 Viscosity 2599 — — 46 2599 — — 93 [mPa*s] Viscosity/M.sub.w 0.0098 — — 0.0009 0.0098 — — 0.0014 [Pa*s*mol/kg]

(64) TABLE-US-00043 Example 16 Reaction time [h] Analytical data 0 1 3 24 M.sub.w [kg/mol] 273 40 28 22 M.sub.n [kg/mol] 75 18 13 11 PDI 3.7 2.2 2.1 2.1 Viscosity [mPa*s] 2599 — — 16 Viscosity/M.sub.w 0.0098 — — 0.0007 [Pa*s*mol/kg]

Experiment 17*: Reaction of HNBR with M73 SIPr Catalyst without Olefin

(65) TABLE-US-00044 Rubber ACN content ML1 + 4 (100° C.) Amount Name Type [% by wt.] [MU] [g] HNBR Therban 3467 34 68 50.20

(66) TABLE-US-00045 Reaction conditions Catalyst Amount Amount Ru based Temperature No. Type [mg] [mmol] on NBR [ppm] [° C.] 17* M73 SIPr 61.9 0.0750 151 100

(67) TABLE-US-00046 Example 18 Reaction time [h] Analytical data 0 24 M.sub.w [kg/mol] 285 186 M.sub.n [kg/mol] 83 71 PDI 3.4 2.6 Viscosity [mPa*s] 3719 1395 Viscosity/M.sub.w 0.0131 0.0075 [Pa*s*mol/kg]

Example 18: Reaction of HNBR with Grubbs-Hoveyda 1 Catalyst without Olefin

(68) TABLE-US-00047 Rubber ACN content ML1 + 4 (100° C.) Amount Name Type [% by wt.] [MU] [g] HNBR Therban 3467 34 68 50.20

(69) TABLE-US-00048 Reaction conditions Catalyst Amount Amount Ru based Temperature No. Type [mg] [mmol] on NBR [ppm] [° C.] 18 Grubbs-Hoveyda II 66.3 0.0750 151 100

(70) The inventive examples 5a*, 5b*, 7a*, 7b*, 8a* and 8b* show that the use of the catalysts M71 SIPr, M73 SIPr and M74 SIPr in the cross-metathesis of nitrile rubber with 1-hexene after reaction times of 24 hours gives lower molar masses (M.sub.w and M.sub.n) than in the non-inventive examples 1a, 1b, 2a, 2b, 3a, 3b, 4a, 4b, 6a and 6b in which the Grubbs-II, Grubbs-Hoveyda, Zhan 1B, M71 SIMes and M73SIMes catalysts were used. The lower molar masses were achieved both with catalyst inputs of 9 ppm of Ru and of 18 ppm of Ru.

(71) In addition, it is shown that, for the achievement of equal final molar masses of the nitrile rubber, in the case of inventive use of the catalysts M71 SIPr, M73 SIPr and M74 SIPr, it is possible to reduce the amounts of ruthenium by comparison with the catalysts Grubbs-II, Grubbs-Hoveyda, Zhan 1B, M71 SIMes and M73 SIMes. The reduction in the amount of costly precious metal enables more economically viable performance of the cross-metathesis of nitrile rubber.

(72) Examples 9, 10* and 11 show that, with identical ruthenium inputs of 67 ppm, the inventive use of M73 SIPr (Example 10*) for the self-metathesis of nitrile rubber (without addition of 1-olefin as co-olefin), the molar mass (M.sub.w and M.sub.n) of the nitrile rubber after a reaction time of 24 hours is lower than in the case of use of M73 SIMes (Example 9) and Grubbs-Hoveyda II (Example 11). Example 10* shows that the inventive use of the catalyst M73 SIPr enables more economical use of ruthenium than with the catalysts used to date for the metathesis of nitrile rubber.

(73) Example 17* shows that the inventive use of the catalyst M73 SIPr in the self-metathesis of partly hydrogenated nitrile rubber, by comparison with the Grubbs-Hoveyda II catalyst (Example 18), after 24 hours, gives lower molar masses (M.sub.W and M). Inventive use of the catalyst M73 SIPr enables more economic use of the costly precious metal ruthenium.

(74) IV Hydrogenations

(75) The hydrogenations which follow were conducted using NBR-8 from ARLANXEO Deutschland GmbH having the characteristics listed in Table 2.

(76) Procedure for the Hydrogenations

(77) Dry monochlorobenzene (MCB) was purchased from VWR and used as obtained. The results of the hydrogenation experiments are summarized in Table 7.

(78) The hydrogenations 1 to 4* were performed in a 101 high-pressure reactor under the following conditions: Solvent: monochlorobenzene Substrate: NBR-8 Solids concentration: 12 wt. % NBR-8 in MCB (518 g) Reactor temperature: 137° C. to 140° C. Reaction time: 4 h Catalyst loading: 0.2027 g (0.04 phr) Hydrogen pressure (p H.sub.2): 8.4 MPa Stirrer speed: 600 rpm

(79) The polymer solution containing NBR-8 is degassed 3 times with H.sub.2 (23° C., 2.0 MPa) under vigorous stirring. The temperature of the reactor was raised to 100° C. and the H.sub.2 pressure to 60 bar. 50 g of a monochlorobenzene solution of the catalyst (0.2027 g) were added and the pressure was raised to 8.4 MPa, while the reactor temperature was adjusted to 138° C. Both parameters were kept constant during the reaction. The progression of the reaction was monitored by means of measurement of the residual double bond content (RDB) of the nitrile rubber by means of IR spectroscopy. The reaction was ended after 4 hours by releasing the hydrogen pressure.

(80) TABLE-US-00049 TABLE 7 Overview of the hydrogenation experiments Nitrile rubber Conc. Catalyst Hydrogenation progress Amount in MCB Amount Amount (RDB in [%]) No. Type [g] [% by wt.] Type [g] [phr] 0 h 1 h 2h 3h 4 h 1 NBR- 518 12 M73 0.2027 0.4 100 43.5 28.7 22.1 17.6 8 SIMes 2 NBR- 518 12 M73 0.2027 0.04 100 2.1 0.8 0.5 0.4 8 SIPr 3 NBR- 518 12 M71 0.2027 0.04 100 1.5 0.4 — — 8 SIMes 4 NBR- 518 12 M71 0.2027 0.04 100 1.5 0.5 — — 8 SIPr

(81) The examples adduced above show an at least equally good or even distinctly faster progression of the hydrogenation for the inventive catalysts M73 SIPr and M71 SIPr under equivalent experimental conditions by comparison with the catalysts M73SIMes and M71 SIMes.