Composite boronized glycerate extreme pressure anti-wear additive as well as preparation method and application thereof

Abstract

The invention discloses a composite boronized glycerate extreme pressure anti-wear additive which comprises borate, a compound (I), a compound (II) and a compound (III), the mass ratio of the compound (I) to the compound (II) to the compound (III) is (9-11): (47-53): (36-46). The invention also discloses a preparation method of the composite boronized glycerate extreme pressure anti-wear additive, which specifically comprises the following steps: mixing glycerol, borate and a solid acid catalyst, adding C4-C24 fatty acid, and carrying out esterification reaction to obtain a boronized fatty glyceride mixture; and mixing a boronizing reagent with a solvent, and adding the boronized fatty glyceride mixture for reaction. The invention also discloses an application of the composite boronized glycerate extreme pressure anti-wear additive in lubricating oil. The anti-wear additive disclosed by the invention is good in oil solubility, excellent in extreme pressure anti-wear performance and good in thermal stability, and does not generate adverse effects on the corrosion performance of lubricating oil.

Description

Technical Field

[0001] The invention belongs to the technical field of extreme pressure anti-wear additive preparation, and specifically relates to a composite boronated glycerate extreme pressure anti-wear additive, and also relates to a preparation method and application of the extreme pressure anti-wear additive. Background Art

[0002] As a new type of environmentally friendly lubricant additive, boron additives have attracted more and more attention due to their unique chemical properties. Boron additives can be divided into inorganic borates and organic borates from the perspective of chemical structure. The oil film formed by inorganic borate additives has good strength. Studies have found that they have good extreme pressure effects under low speed and high torque and high speed and low torque conditions. At the same time, inorganic borate additives have high thermal stability and can be used stably for a long time even at a high temperature of 150°C. On the other hand, the extreme pressure performance of inorganic borate additives is less dependent on the thickness of the oil film. The extreme pressure performance of inorganic borate additives in lubricating oil will not decrease with the decrease of oil viscosity, and can well cope with the challenge of low viscosity of oil products brought about by fuel economy requirements. Although inorganic borates have excellent thermal stability and good tribological properties such as anti-wear, friction reduction, and extreme pressure, the low solubility of inorganic borates in lubricating oil has become the main problem restricting its development. Attempts have been made to improve the dispersion stability of inorganic borates in base oil by reducing inorganic borate particles and surface modifying inorganic borates, but the results are not ideal.

[0003] Boric acid ester additives not only have excellent thermal oxidation stability and sealing adaptability, no corrosion to copper at high temperature, good anti-rust performance for steel, but also help improve the operating environment, have excellent load-bearing capacity and anti-friction and anti-wear performance, and have been widely used in engine oils and industrial gear oils. In recent years, in order to improve the performance of boric acid ester lubricant additives, the introduction of active elements such as N, S, and P into boric acid ester molecules has become a research hotspot. Introducing nitrogen atoms into the molecular structure of boric acid esters so that nitrogen atoms and boron atoms form BN coordination bonds is currently an effective method for improving the hydrolysis stability of boric acid esters. This type of boric acid ester is generally formed by directly reacting a hydroxyl-containing long-chain amine with boric acid to form an ester. Most of these amine-containing boric acid esters have good friction reduction performance and high thermal oxidation stability. Sulfur-containing boric acid esters are generally formed by reacting S-containing monohydroxyl compounds or polyhydroxyl compounds with boric acid to form an ester. The above research works have improved the performance of borate additives in different aspects, but the introduction of some active elements has limited the application of additives to a certain extent. The development of oil technology has put forward new requirements for additives. Engine oil has made stricter restrictions on the S and P elements of additives. GF-6 engine oil requires that the S element is not more than 0.5% and the P element is not more than 0.08%. High-end industrial gear oils are paying more and more attention to the odor, biodegradability, and whether they meet food-grade certification requirements of additives. The development of low-sulfur, low-phosphorus biodegradable borate additives will be a way to meet the demand for new oil products.

[0004] The molecular adjustability of fatty acid glycerides is strong, triglycerides have good thermal stability, and the molecules of monoglycerides and diesters contain adsorption groups such as ester bonds and hydroxyls, which have good lubrication properties. Borates, glycerol, fatty acids and boronization reagents are appropriately compounded to synthesize a composite boronized glycerate extreme pressure anti-wear additive through reaction. The reasonable introduction of borates can improve the oil solubility of the additive on the one hand, and improve the thermal stability and extreme pressure performance of the additive on the other hand. Summary of the invention

[0005] The purpose of the present invention is to provide a composite boronated glycerate extreme pressure anti-wear additive, which has good oil solubility and excellent extreme pressure anti-wear and thermal stability.

[0006] Another object of the present invention is to provide a method for preparing the composite boronated glycerate extreme pressure and anti-wear additive.

[0007] The technical solution adopted by the present invention is that the composite boronated glycerate extreme pressure anti-wear additive includes: borate, compound (one), compound (two), compound (three); the mass ratio of compound (one), compound (two), compound (three) is 9-11:47-53:36-46.

[0008] The structure of compound (I) is shown in Formula I:

[0009]

[0010] In Formula I, R1, R2 and R3 are C3-C 23 of hydrocarbon groups.

[0011] The structure of compound (II) is shown in formula II:

[0012]

[0013] In Formula II, R is selected from C3-C 23 The hydrocarbon group, R5 is selected from C4-C 24 Alkyl or C6-C 18 The aromatic group.

[0014] The structure of compound (III) is shown in formula III:

[0015]

[0016] In Formula III, R5 is selected from C4-C 24 Alkyl or C6-C 18 R4 and R6 are or R4 and R6 are the same or different;

[0017] Wherein, R7 and R8 are the same or different, and R7 and R8 are C3-C 23 of hydrocarbon groups.

[0018] The borate is any one of sodium borate, potassium borate, calcium borate and magnesium borate.

[0019] Another technical solution adopted by the present invention is a method for preparing a composite boronated glycerate extreme pressure and anti-wear additive, which is specifically implemented according to the following steps:

[0020] Step 1: Mix glycerol, borate and solid acid catalyst, heat until the borate is dissolved, and add C4-C 24 The fatty acid is subjected to esterification reaction, and an inert gas with water is introduced. When no water is produced in the reaction system, the reaction is stopped and filtered to obtain a boronated fatty acid glyceride mixture;

[0021] Step 2, mixing the boronation reagent and the solvent, adding the boronated fatty acid glyceride mixture obtained in step 1, introducing inert gas with water, reacting, and removing the solvent by vacuum distillation to obtain a composite boronated glyceride extreme pressure and anti-wear additive.

[0022] The present invention is also characterized in that:

[0023] In step 1, the borate is any one of sodium borate, potassium borate, calcium borate and magnesium borate; the amount of borate added is C4-C24 2wt%-26wt% of the total mass of fatty acids and glycerol.

[0024] C4-C 24 The molar ratio of fatty acid and glycerol calculated by carboxyl group to hydroxyl group is 1.1-1.8:3; the amount of solid acid catalyst added is C4-C 24 The solid acid catalyst comprises one or a combination of two or more of Al2O3-SiO2, molecular sieve ZSM-5, and MCM-41; the esterification reaction temperature is 90-180°C, and the esterification reaction time is 2-12h.

[0025] In step 2, the boronating agent is any one or both of an alkyl boronic acid and an aryl boronic acid; the boronating agent has a structure shown in formula IV:

[0026]

[0027] In Formula IV, R5 is selected from C4-C 24 Alkyl or C6-C 18 The aromatic group;

[0028] The molar amount of the boronating agent added is [(3a-b) / 2] to (3a-b), wherein a is the molar amount of glycerol added, and b is the molar amount of C4-C 24 The total molar amount of fatty acids added.

[0029] In step 2, the solvent is one or a combination of two or more of petroleum ether, benzene, toluene, cyclohexane, n-heptane, n-octane, and xylene, and the amount of solvent added is 50wt%-150wt% of the total mass of the fatty acid glyceride mixture; the reaction temperature is 80-170°C, and the reaction time is 3-12h.

[0030] The beneficial effect of the present invention is that, by utilizing the good solubility of borates in glycerol, a boronated fatty acid glyceride mixture of a specific composition is prepared by reacting fatty acids with glycerol, and then the boronated fatty acid glyceride and a boronating agent are reacted in a certain proportion through a one-step esterification reaction to synthesize a composite boronated glyceride additive. The production process is simple and easy to operate, safe and environmentally friendly, the post-treatment process is simple, and the production cost is low. Different series of extreme pressure anti-wear additive products can be prepared according to specific needs. The product has good oil solubility, excellent anti-wear performance and good thermal stability, and will not have adverse effects on the corrosion performance of lubricating oil. DETAILED DESCRIPTION

[0031] The present invention is described in detail below through specific implementation modes.

[0032] The composite boronized glycerate extreme pressure and anti-wear additive of the present invention comprises: borate, compound (I), compound (II), and compound (III); the mass ratio of compound (I), compound (II), and compound (III) is 9-11:47-53:36-46;

[0033] The structure of compound (I) is shown in Formula I:

[0034]

[0035] In Formula I, R1, R2 and R3 are C3-C 23 A hydrocarbon group; R1, R2 and R3 may be the same or different;

[0036] The structure of compound (II) is shown in formula II:

[0037]

[0038] In Formula II, R is selected from C3-C 23 The hydrocarbon group, R5 is selected from C4-C 24 Alkyl or C6-C 18 The aromatic group;

[0039] The structure of compound (III) is shown in formula III:

[0040]

[0041] In Formula III, R5 is selected from C4-C 24 Alkyl or C6-C 18 R4 and R6 are or R4 and R6 are the same or different;

[0042] Wherein, R7 and R8 are the same or different, and R7 and R8 are C3-C 23 The hydrocarbon group;

[0043] The preparation method of the composite boronated glycerate extreme pressure and anti-wear additive of the present invention is specifically implemented according to the following steps:

[0044] Step 1: Mix glycerol, borate and solid acid catalyst, heat until the borate is dissolved, and add C4-C 24 The fatty acid is subjected to esterification reaction, and an inert gas with water is introduced. When no water is produced in the reaction system, the reaction is stopped and filtered to obtain a boronated fatty acid glyceride mixture;

[0045] The borate is any one of sodium borate, potassium borate, calcium borate and magnesium borate;

[0046] The amount of borate added is C4-C 242wt%-26wt% of the total mass of fatty acids and glycerol;

[0047] C4-C 24 The molar ratio of fatty acids and glycerol calculated by carboxyl groups and hydroxyl groups is 1.1-1.8:3.

[0048] The esterification reaction temperature is 90-180°C, and the esterification reaction time is 2-12h;

[0049] The solid acid catalyst includes one or a combination of two or more of Al2O3-SiO2, molecular sieve ZSM-5, and MCM-41;

[0050] The amount of solid acid catalyst added is C4-C 24 0.05wt%-1.2wt% of the total mass of fatty acids and glycerol;

[0051] Step 2, mixing the boronization reagent and the solvent, adding the boronized fatty acid glyceride mixture obtained in step 1, passing an inert gas with water, heating to 80-170° C., reacting for 3-12 hours, and removing the solvent by vacuum distillation to obtain a composite boronized glyceride extreme pressure and anti-wear additive;

[0052] The boronating agent is any one or both of an alkyl boronic acid and an aryl boronic acid; the boronating agent has a structure shown in Formula IV:

[0053]

[0054] In Formula IV, R5 is selected from C4-C 24 Alkyl or C6-C 18 The aromatic group;

[0055] The molar amount of the boronating agent added is [(3a-b) / 2] to (3a-b), wherein a is the molar amount of glycerol added, and b is the molar amount of C4-C 24 The total molar amount of fatty acids added;

[0056] The solvent is one or a combination of two or more of petroleum ether, benzene, toluene, cyclohexane, n-heptane, n-octane and xylene. The amount of solvent added is 50wt%-150wt% of the total mass of the fatty acid glyceride mixture.

[0057] The inert gas is either nitrogen or helium, or both.

[0058] The present invention also provides a lubricating oil, which includes a composite boronized glycerate extreme pressure anti-wear additive. The composite boronized glycerate extreme pressure anti-wear additive can be used as a lubricating oil additive alone, or can be used in combination with other lubricating oil additives.

[0059] Preferably, the boronated fatty acid glyceride anti-wear additive is added to the lubricating oil in an amount of 0.1 wt% to 11 wt%.

[0060] In the method of the present invention, firstly, the good solubility of borate in glycerol is utilized to prepare a boronized fatty acid glyceride mixture of a specific composition by reacting fatty acids with glycerol, and then the boronized fatty acid glyceride and a boronating agent are subjected to a one-step esterification reaction in a certain proportion to synthesize a composite boronized glyceride additive. The production process is simple and easy to operate, safe and environmentally friendly, the post-treatment process is simple, and the production cost is low. Different series of extreme pressure anti-wear additive products can be prepared according to specific needs. The product has good oil solubility, excellent anti-wear performance and good thermal stability, and will not have adverse effects on the corrosion performance of lubricating oil.

[0061] Example 1

[0062] This embodiment provides a composite boronated glycerate extreme pressure and anti-wear additive, and the preparation method thereof is as follows:

[0063] (1) 8.6 g potassium borate, 92.1 g glycerol (1 mol) and 2.16 g Al2O3-SiO2 catalyst were added to a reactor, stirred and mixed evenly, 339 g oleic acid (1.2 mol) was added dropwise, the temperature was raised to 180° C., nitrogen was used to carry water, and the reaction was continued for 5 hours. When no water was produced in the system, the reaction was stopped and filtered to obtain boronized oleic acid glyceride;

[0064] (2) 121.9 g of phenylboric acid (1 mol) and 400 g of petroleum ether were added to a reaction vessel, stirred and mixed evenly, and the boronized oleic acid glyceride in step (1) was added, nitrogen was passed through with water, the temperature was raised to 95° C., the reaction was continued for 4 hours, and the solvent was removed by reduced pressure distillation to obtain a composite boronized oleic acid glyceride extreme pressure and anti-wear additive A.

[0065] Example 2

[0066] This embodiment provides a composite boronated glycerate extreme pressure and anti-wear additive, and the preparation method thereof is as follows:

[0067] (1) 72.7 g of sodium borate, 92.1 g of glycerol (1 mol) and 0.22 g of ZSM-5 catalyst were added to a reactor, stirred and mixed uniformly, 187.5 g of isooctanoic acid (1.3 mol) was added dropwise, the temperature was raised to 170° C., nitrogen was used to carry water, and the reaction was continued for 4.5 hours. When no water was produced in the system, the reaction was stopped and filtered to obtain boronized isooctanoic acid glyceride;

[0068] (2) 142.2 g of octylboric acid (0.9 mol) and 300 g of toluene were added to a reaction container, stirred and mixed evenly, and the boronized isooctanoic acid glyceryl ester in step (1) was added, nitrogen was passed through with water, the temperature was raised to 90° C., the reaction was continued for 5 hours, and the solvent was removed by reduced pressure distillation to obtain a composite boronized isooctanoic acid glyceryl ester extreme pressure and anti-wear additive B.

[0069] Example 3

[0070] This embodiment provides a composite boronated glycerate extreme pressure and anti-wear additive, and the preparation method thereof is as follows:

[0071] (1) 11.2 g of calcium borate, 92.1 g of glycerol (1 mol) and 3.6 g of MCM-41 catalyst were added to a reactor, stirred and mixed evenly, 356.2 g of hexadecenoic acid (1.4 mol) was added dropwise, the temperature was raised to 160° C., nitrogen was used to carry water, and the reaction was continued for 4 hours. When no water was produced in the system, the reaction was stopped and filtered to obtain boronated hexadecenoic acid glyceride;

[0072] (2) 136 g of p-methylphenylboric acid (1 mol) and 300 g of xylene are added to a reaction container, stirred and mixed evenly, and the boronized hexadecenoic acid glyceryl ester in step (1) is added, nitrogen is passed through with water, the temperature is raised to 105° C., the reaction is continued for 6 hours, and the solvent is removed by reduced pressure distillation to obtain a composite boronized hexadecenoic acid glyceryl ester extreme pressure and anti-wear additive C.

[0073] Example 4

[0074] This embodiment provides a composite boronated glycerate extreme pressure and anti-wear additive, and the preparation method thereof is as follows:

[0075] (1) 40.8 g of magnesium borate, 46.1 g of glycerol (0.5 mol) and 2.16 g of Al2O3-SiO2 catalyst were added to a reactor, stirred and mixed evenly, 226 g of oleic acid (0.8 mol) was added dropwise, the temperature was raised to 155° C., industrial helium was used to carry water, and the reaction was continued for 8 hours. When no water was produced in the system, the reaction was stopped and filtered to obtain boronized oleic acid glyceride;

[0076] (2) 54.4 g of p-methylphenylboric acid (0.4 mol) and 200 g of toluene were added to a reaction container, stirred and mixed evenly, and the boronized oleic acid glyceride in step (1) was added, helium gas was passed through with water, the temperature was raised to 110° C., the reaction was continued for 8 hours, and the solvent was removed by reduced pressure distillation to obtain a composite boronized oleic acid glyceride extreme pressure and anti-wear additive D.

[0077] Comparative Example 1

[0078] This comparative example is a boronized fatty acid glyceride anti-wear additive, and its preparation method is as follows:

[0079] (1) 92.1 g of glycerol (1 mol) and 2.16 g of Al2O3-SiO2 catalyst were added to a reactor, stirred and mixed evenly, 339 g of oleic acid (1.2 mol) was added dropwise, the temperature was raised to 150° C., nitrogen was used to carry water, and the reaction was continued for 5 hours. When no water was produced in the system, the reaction was stopped and filtered to obtain oleic acid glyceride;

[0080] (2) 121.9 g of phenylboric acid (1 mol) and 400 g of petroleum ether were added to a reaction vessel, stirred and mixed evenly, and olein from step (1) was added, nitrogen was used to carry water, and the temperature was raised to 95° C. After continuing the reaction for 4 hours, the solvent was removed by distillation under reduced pressure to obtain boronized olein anti-wear additive E.

[0081] Comparative Example 2

[0082] This comparative example is a boronized fatty acid glyceride anti-wear additive, and its preparation method is as follows:

[0083] (1) 92.1 g of glycerol (1 mol) and 2.16 g of Al2O3-SiO2 catalyst were added to a reactor, stirred and mixed evenly, 339 g of oleic acid (1.2 mol) was added dropwise, the temperature was raised to 150° C., nitrogen was used to carry water, and the reaction was continued for 5 hours. When no water was produced in the system, the reaction was stopped and filtered to obtain oleic acid glyceride;

[0084] (2) 61.83 g of boric acid (1 mol) and 400 g of petroleum ether were added to a reaction vessel, stirred and mixed evenly, and the olein in step (1) was added, nitrogen was used to carry water, and the temperature was raised to 95° C. After continuing the reaction for 4 hours, the solvent was removed by distillation under reduced pressure to obtain the boronized olein anti-wear additive F.

[0085] Comparative Example 3

[0086] This comparative example is a boronized fatty acid glyceride anti-wear additive, and its preparation method is as follows:

[0087] (1) 8.6 g of potassium borate, 92.1 g of glycerol (1 mol) and 2.16 g of Al2O3-SiO2 catalyst were added to a reactor, stirred and mixed evenly, 339 g of oleic acid (1.2 mol) was added dropwise, the temperature was raised to 180°C, nitrogen was used to carry water, and the reaction was continued for 5 hours. When no water was produced in the system, the reaction was stopped and filtered to obtain boronated oleic acid glyceride G.

[0088] Comparative Example 4

[0089] This comparative example is a boronized fatty acid monoglyceride anti-wear additive, and its preparation method is as follows:

[0090] 136 g of p-methylphenylboric acid (1 mol) and 400 g of petroleum ether were added into a reaction vessel, stirred and mixed evenly, 164.3 g of glycerol monohexadecenoate (0.5 mol) was added, nitrogen was passed through with water, the temperature was raised to 105°C, the reaction was continued for 6 hours, and the solvent was removed by reduced pressure distillation to obtain the boronated hexadecenoic acid monoglyceride anti-wear additive G.

[0091] The boronized fatty acid glyceride anti-wear additive obtained in the examples and comparative examples was added to GL-5 gear oil in an amount of 1.0 wt %. The wear spot diameter and sintering load (P D The friction coefficient under a load of 392N and the copper sheet corrosion performance were measured, and the results are shown in Table 1. At the same time, the prepared oil was stored at 0℃ for 90 days to investigate the storage stability of the oil.

[0092] The maximum no-seizure load (P D The wear spot diameter of the steel ball was determined according to the method of NB / SH / T 0189-2017, the friction coefficient was determined according to the method of SH / T0762-2005, and the copper sheet corrosion was determined according to the method of GB / T 5096-2017.

[0093] Table 1 Performance evaluation of composite boronated glycerol ester extreme pressure and anti-wear additives

[0094]

[0095] The results show that the composite boronated glycerol ester extreme pressure anti-wear additive of the present invention has good oil solubility, excellent extreme pressure anti-wear and friction reduction properties, and has no adverse effect on the corrosion performance of the lubricating oil.

Claims

1. A composite boronized glycerate extreme pressure anti-wear additive, characterized in that: include: The mass ratio of borate, compound (I), compound (II), compound (III); compound (I), compound (II), compound (III) is 9-11:47-53:36-46.

2. The composite boronated glycerate extreme pressure anti-wear additive according to claim 1, characterized in that: The borate is any one of sodium borate, potassium borate, calcium borate and magnesium borate.

3. The composite boronated glycerate extreme pressure and anti-wear additive according to claim 1, characterized in that: The structure of the compound (I) is shown in Formula I: In Formula I, R1, R2 and R3 are C3-C 23 The hydrocarbon group; The structure of the compound (II) is shown in Formula II: In Formula II, R is selected from C3-C 23 The hydrocarbon group, R5 is selected from C4-C 24 Alkyl or C6-C 18 The aromatic group; The structure of the compound (III) is shown in Formula III: In Formula III, R5 is selected from C4-C 24 Alkyl or C6-C 18 R4 and R6 are or R4 and R6 are the same or different; Wherein, R7 and R8 are the same or different, and R7 and R8 are C3-C 23 of hydrocarbon groups.

4. The method for preparing the composite boronated glycerate extreme pressure and anti-wear additive according to any one of claims 1 to 3, characterized in that: Follow the steps below to implement it: Step 1: Mix glycerol, borate and solid acid catalyst, heat until the borate is dissolved, and add C4-C 24 The fatty acid is subjected to esterification reaction, and an inert gas with water is introduced. When no water is produced in the reaction system, the reaction is stopped and filtered to obtain a boronated fatty acid glyceride mixture; Step 2, mixing the boronation reagent and the solvent, adding the boronated fatty acid glyceride mixture obtained in step 1, introducing inert gas with water, reacting, and removing the solvent by vacuum distillation to obtain a composite boronated glyceride extreme pressure and anti-wear additive.

5. The method for preparing the composite boronated glycerate extreme pressure and anti-wear additive according to claim 4, characterized in that: In step 1, the borate is any one of sodium borate, potassium borate, calcium borate and magnesium borate; the amount of borate added is C4-C 24 2wt%-26wt% of the total mass of fatty acids and glycerol.

6. The method for preparing the composite boronated glycerate extreme pressure and anti-wear additive according to claim 4, characterized in that: The C4-C 24 The molar ratio of fatty acid and glycerol calculated by carboxyl group to hydroxyl group is 1.1-1.8:3; the amount of solid acid catalyst added is C4-C 24 The solid acid catalyst comprises one or a combination of two or more of Al2O3-SiO2, molecular sieve ZSM-5, and MCM-41; the esterification reaction temperature is 90-180°C, and the esterification reaction time is 2-12h.

7. The method for preparing the composite boronated glycerate extreme pressure and anti-wear additive according to claim 4, characterized in that: In step 2, the boronating agent is any one or both of an alkyl boronic acid and an aryl boronic acid; the boronating agent has a structure shown in formula IV: In Formula IV, R5 is selected from C4-C 24 Alkyl or C6-C 18 The aromatic group; The molar amount of the boronating agent added is [(3a-b) / 2] to (3a-b), wherein a is the molar amount of glycerol added, and b is the molar amount of C4-C 24 The total molar amount of fatty acids added.

8. The method for preparing the composite boronated glycerate extreme pressure and anti-wear additive according to claim 4, characterized in that: In the step 2, the solvent is one or a combination of two or more of petroleum ether, benzene, toluene, cyclohexane, n-heptane, n-octane, and xylene, and the amount of solvent added is 50wt%-150wt% of the total mass of the fatty acid glyceride mixture; the reaction temperature is 80-170°C, and the reaction time is 3-12h.

9. Use of the composite boronated glycerate extreme pressure anti-wear additive as claimed in claim 1 in lubricating oil.

10. The use according to claim 9, characterized in that The addition amount of the composite boronated glycerate extreme pressure anti-wear additive in the lubricating oil is 0.1wt%-11wt%.

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