Method for improving aging resistance of asphalt by modifying asphalt through halogenation, aryl acylation and alkylation reaction

Abstract

A method for improving the anti-aging performance of asphalt by modifying asphalt through halogenation, aryl acylation and alkylation reaction comprises the following steps: heating 70 # matrix asphalt to 130-180 DEG C, adding a modifier and a catalyst to obtain a mixture, heating, stirring, discharging after the reaction is finished, forming, and preparing a sample to obtain modified asphalt; according to the preparation method, an organic chemistry strategy is adopted, a cheap halogenation reagent, an aryl acylation reagent and a Michael acceptor are adopted, aromatic groups in the asphalt are subjected to halogenation reaction / acylation reaction / alkylation reaction under the heating condition, the asphalt is modified on the molecular level, aromatic components in the asphalt are more stable, and the asphalt is more stable. Oxidation or polycondensation reaction is not easy to occur, so that the anti-aging performance is fundamentally improved, the reaction conditions in the whole modification process are simple, and industrial application is facilitated.

Description

Technical Field

[0001] The present invention belongs to the technical field of asphalt modification, and in particular relates to a method for improving the anti-aging performance of asphalt by modifying asphalt through halogenation, aromatic acylation and alkylation reactions. Background Art

[0002] As an important global chemical material, petroleum asphalt is widely used in waterproofing, anti-corrosion, chemical raw materials and other fields. Asphalt is a viscoelastic material with time and temperature dependence. At low temperatures, asphalt behaves like a brittle material and is prone to cracking even under moderate loads. At moderate temperatures, asphalt becomes a viscoelastic liquid, and as the temperature continues to rise, the asphalt behaves like a Newtonian fluid.

[0003] In terms of chemical composition, asphalt is a complex mixture of hydrocarbons, which also contains small amounts of sulfur, oxygen, nitrogen and trace metals such as vanadium, iron, nickel, calcium and magnesium. In order to analyze and identify the components of asphalt, the SARA analysis method is usually used, which is to subdivide a large number of asphalt molecules into a limited number of fractions according to the polarity of their chemical components. According to the SARA analysis method, the composition of asphalt is divided into four components: saturate, aromatic, resin and asphaltene.

[0004] The research on modified asphalt first began abroad. Since France used natural rubber to prepare modified asphalt in the 19th century, the research and development of modified asphalt has a history of hundreds of years. Through a large amount of preliminary literature research, among the four components of asphalt, the saturated components are generally more stable and not easy to undergo chemical changes under normal conditions. As for the other three components, because they contain aromatic or condensed aromatic structures, they are prone to oxidation or polycondensation reactions under certain conditions, causing the asphalt to become hard and brittle. Therefore, various modifiers can be added to the base asphalt to improve its various properties. The article "Research Status and Prospects of Modified Asphalt" published in Volume 32, Issue 6, REFINING AND CHEMICAL INDUSTRY on September 21, 2021, introduces the current methods of modifying asphalt, including nanomaterial modified asphalt, fiber material modified asphalt, waste material modified asphalt, chemical modifier modified asphalt, bio-asphalt, etc. Among them, Ma Qingfeng et al. used polyphosphoric acid (PPA) and matrix asphalt to prepare PPA modified asphalt in chemically modified asphalt, and experimental analysis showed that the high temperature anti-rutting performance of PPA modified asphalt mixture was greatly improved. However, there are very few reports on asphalt modification by organic chemical methods. Summary of the invention

[0005] In order to overcome the defects of the above-mentioned prior art, the purpose of the present invention is to provide a method for improving the anti-aging performance of asphalt by halogenation, aromatic acylation and alkylation reaction; improving various properties of asphalt by organic chemical methods, the catalyst used is low in cost, and the existing asphalt is easily affected by environmental factors such as light, heat, oxygen, water, etc., and the asphalt itself is prone to aging reaction, resulting in reduced ductility, increased viscosity, increased softening point, decreased penetration, and even hardening and brittleness, which leads to a significant reduction in the service life of asphalt pavement or asphalt waterproofing materials and the inability to meet environmental use requirements.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for improving the anti-aging performance of asphalt by halogenation, aromatic acylation and alkylation reaction, comprising the following steps:

[0008] (1) Akg70# base asphalt is heated to 130°C to 180°C, and Bkg modifier and Cmol catalyst are added to obtain a mixture; A:B = (10-40): 1; C = (B / M)*(5%-10%), where M is the molecular weight of the added modifier;

[0009] (2) heating and stirring the mixture of step (1), discharging, shaping and sampling after the reaction is completed to obtain modified asphalt.

[0010] The modifier includes a halogenating agent, an aromatic acylating agent or a Michael acceptor; the halogenating agent includes NBS, NCS, DCH, TCCA, NCSac, NCP, DBH, PHP, DBI, TBCA, NBSac, NBP, NIS, NIP, N-fluorobisbenzenesulfonamide, trichloromelamine, sodium dichloroisocyanurate, carbon tetrabromide, dibromohydantoin or dichlorohydantoin; the aromatic acylating agent includes acetic anhydride, trichloroacetyl chloride, p-nitrobenzoyl chloride, o-nitrobenzenesulfonyl chloride, benzenesulfonyl chloride, trifluoroacetic anhydride, phthalic anhydride, phosphoric anhydride, permanganic anhydride, chloroacetyl chloride, thionyl chloride, dimethylformamide, sulfonamide or benzenesulfonamide; the Michael acceptor includes methyl acrylate, benzyl acrylate, N-phenylmaleimide, acrylonitrile, maleic anhydride, N-chlorophthalimide or 2-methylacrolein.

[0011] The catalyst comprises a Lewis acid catalyst or a Bronsted acid catalyst, wherein the Lewis acid catalyst comprises AlCl3, FeCl3, NiCl2, CuCl2·2H2O, MgCl2, ZnCl2, MnCl2, MnCl2·4H2O, SnCl2, Al(NO3)3·9H2O, Ni(NO3)2, Zn(NO3)2·6H2O, Cu(NO3)2·3H2O, Cr(NO3)2, Co(NO 3)2, Cu(OAc)2·H2O, Pd(OAc)2, Ni(OAc)2, Cd(OAc)2·2H2O, Fe(acac)2, FeBr2, NiBr2, CuCO3, CuSO4, CuS·H2O, In(OTf)3, Sc(OTf)3, Ga(OTf)3, Yb(OTf)3, Zn(OTf)2 or Y(OTf)3; the Bronsted acid includes formic acid, acetic acid or p-toluenesulfonic acid.

[0012] The heating temperature of step (2) is between 130°C and 180°C.

[0013] The stirring speed of step (2) is controlled at 1000 r / min-1500 r / min.

[0014] The stirring time of step (2) is controlled within 1 h to 2 h.

[0015] The modifier is a halogenating agent, and when it is NBS, the catalyst used is FeCl3.

[0016] The modifier is an aromatic acylating agent, and when it is acetic anhydride, the catalyst used is FeCl3, NiBr2, Ni(NO3)2 or CuS·H2O.

[0017] When the modifier is a Michael acceptor and is benzyl acrylate, the catalyst used is FeCl3.

[0018] A modified asphalt is prepared by the above steps.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. By adding different halogenating agents and various catalysts, under specific conditions, halogen atoms are introduced into the aromatic components of the base asphalt, so that the electronegativity of the aromatic components, which originally have electron-deficient properties, is weakened, making it less likely to undergo oxidation or polycondensation reactions, thereby making the asphalt as a whole stable and less prone to aging.

[0021] 2. By adding different aromatic acylating agents and various catalysts, under specific conditions, acyl groups are introduced into the aromatic components of the base asphalt, which reduces the molecular activity of the aromatic components of the base asphalt and makes it less prone to oxidation or polycondensation reactions, thereby making the asphalt as a whole more stable and less prone to aging.

[0022] 3. By adding different Michael acceptors and various catalysts, under specific conditions, alkyl groups are introduced into the aromatic components of the base asphalt to neutralize the electrical properties, weaken the nucleophilicity of the aromatic components of the base asphalt, and make it less prone to oxidation or polycondensation reactions, thereby making the asphalt as a whole stable and less prone to aging.

[0023] In summary, the present invention adopts the strategy of organic chemistry, using cheap halogenating reagents, aromatic acylating reagents and Michael acceptors. Under heating conditions, the aromatic groups in the asphalt undergo halogenation reaction / acylation reaction / alkylation reaction, and the asphalt is modified at the molecular level, making the aromatic components in the asphalt more stable and less prone to oxidation or polycondensation reactions, thereby fundamentally improving its anti-aging performance. The reaction conditions of the entire modification process are simple, which is conducive to industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the AFM image of 70# matrix asphalt.

[0025] Figure 2 AFM images of AlCl3 and NBS modified asphalt.

[0026] Figure 3 AFM images of FeCl3 and NBS modified asphalt.

[0027] Figure 4 AFM images of NiCl2 and NBS modified asphalt.

[0028] Figure 5 It is the reaction principle diagram of the present invention. DETAILED DESCRIPTION

[0029] The invention is described in detail below in conjunction with the accompanying drawings, but this should not be used as a limitation to the protection scope of the invention.

[0030] It should be noted that, unless otherwise specified, the operations used in the embodiments, such as mixing, discharging, and sample preparation, are all routine operations in the art. The drugs and reagents used in the examples are all commercially purchased analytically pure.

[0031] Example 1

[0032] like Figure 5As shown, this embodiment uses halogenation reaction, aromatic acylation reaction, and alkylation reaction to modify the aromatic component of asphalt, thereby improving its stability, making it less prone to oxidation or polycondensation reaction, and fundamentally improving its anti-aging performance. Specifically, the modified asphalt preparation method includes the following steps:

[0033] (1) Add 70# base asphalt to a 1L metal barrel, place the barrel on a heating mantle and heat to 180°C, 150°C or 130°C, add B kg halogenating agent / acylating agent / Michael acceptor, C mol catalyst; A:B = 10-40:1; C = (B / M)*(5%-10%), M is the molecular weight of the added modifier; use a cylindrical TM-5000 digital temperature-controlled electric heating mantle for heating.

[0034] The halogenating agent includes NBS, NCS, DCH, TCCA, NCSac, NCP, DBH, PHP, DBI, TBCA, NBSac, NBP, NIS, NIP, N-fluorobisbenzenesulfonamide, trichloromelamine, sodium dichloroisocyanurate, carbon tetrabromide, dibromohydantoin or dichlorohydantoin.

[0035] The aromatic acylating agent includes acetic anhydride, trichloroacetyl chloride, p-nitrobenzoyl chloride, o-nitrobenzenesulfonyl chloride, benzenesulfonyl chloride, trifluoroacetic anhydride, phthalic anhydride, phosphoric anhydride, permanganic anhydride, chloroacetyl chloride, thionyl chloride, dimethylformamide, sulfonamide or benzenesulfonamide.

[0036] The Michael acceptor includes methyl acrylate, benzyl acrylate, N-phenylmaleimide, acrylonitrile, maleic anhydride, N-chlorophthalimide or 2-methylacrolein.

[0037] The catalyst includes a Lewis acid catalyst or a Bronsted acid catalyst.

[0038] (2) The heating temperature of the mixture in step (1) is maintained at 180° C., 150° C. or 130° C., the speed of the shear mixer is controlled at 1000 r / min-1500 r / min, and the stirring time is controlled at 1 h-2 h. After the reaction is completed, the mixture is discharged, shaped, and sampled, and then its performance is tested.

[0039] Specifically, the asphalt sample preparation process is as follows: first lay an aluminized film on a flat table and fix it with a clamp, pour the reacted asphalt on the aluminized film, then cover the asphalt with a layer of PET molding mold, and use an iron rod to roll and flatten it to obtain the asphalt waterproof membrane.

[0040] The present invention determines the asphalt modification result through a low temperature flexibility test according to GB / T 328.1-2007 test method for building waterproofing membranes.

[0041] Example 2: Bromination reaction to modify asphalt

[0042] The reaction conditions were screened in accordance with the preparation method of Example 1, see the table below for details.

[0043] The low temperature flexibility results of the prepared bromination reaction modified asphalt are shown in Table 1.

[0044] Table 1 Screening of bromination reaction catalysts

[0045]

[0046]

[0047] Through the screening of catalysts, it can be seen that the modification effects of FeCl3 and AlCl3 are relatively good, reaching -8~-9℃ and -9~-10℃ respectively, which are greatly improved compared with the base asphalt. Some other catalysts such as FeBr3, CuBr2, CuCl2, NiCl2, NiBr2, and Co(OAc)2 also have good improvements on the low-temperature flexibility of the base asphalt, and their low-temperature flexibility can reach -4~-5℃ and -3~-4℃. The other catalysts have little improvement on the low-temperature flexibility of asphalt.

[0048] Afterwards, control tests were conducted using asphalt modified with FeCl3 and AlCl3, which had good test results. It was found that the low-temperature flexibility test performance decreased significantly in the absence of bromination reagent or catalyst, as shown in Table 2:

[0049] Table 2 Control test of bromination reaction

[0050]

[0051]

[0052] It can be seen from Table 3 that in this reaction, both the halogenating agent and the catalyst are necessary. It is speculated that the added halogenating agent and the catalyst cause the aromatic components in the asphalt to undergo a halogenation reaction.

[0053] Table 3 Screening of halogenating agents

[0054] Halogenating agent (10%) Catalyst (10 mol%) Low temperature flexibility(℃) Dibromohydantoin <![CDATA[AlCl3]]> -2～-3 Dibromohydantoin <![CDATA[FeCl3]]> 0～-1 NCS <![CDATA[AlCl3]]> 0～1 NCS <![CDATA[FeCl3]]> 0～1

[0055] After that, FeCl3 and AlCl3 were used to screen the halogenation reagents (Table 3). It was found that the low-temperature flexibility of the modified asphalt prepared by using dibromohydantoin as the bromination reagent and FeCl3 and AlCl3 as the catalyst was -2 to -3°C and 0 to 1°C, respectively, while the low-temperature flexibility of the modified asphalt prepared by using NCS as the bromination reagent and FeCl3 and AlCl3 as the catalyst was only 0 to 1°C. Therefore, compared with other bromination reagents, NBS can be used as a cheap and efficient halogenation reagent for modified asphalt.

[0056] Example 3: Aromatic acylation reaction to modify asphalt

[0057] Initial reaction conditions and steps:

[0058] Add 300g of base asphalt into a 1L metal barrel, then heat to 180°C, add acylating agent (30g, 10% by mass), and then add catalyst (10mol% of aromatic acylating agent), control the speed of the shear mixer at 1500r / min, and the stirring time at 1h, then discharge, shape and prepare samples.

[0059] First, acetic anhydride was used as the acylating agent to screen the catalyst, and then the low-temperature flexibility test of the modified asphalt was carried out (Table 4)

[0060] Table 4 Screening of acylation catalysts

[0061]

[0062]

[0063] When acetic anhydride is used as the acylating agent, it can be seen from Table 4 that the low-temperature flexibility of FeCl3, NiBr2, Ni(NO3)2 and CuS·H2O can reach -3~-4℃. The low-temperature flexibility of asphalt modified by other catalysts such as CuCO3, ZnCl2, Ni(OAc)2 and MnCl2·4H2O can also reach -2~-3℃. It is worth noting that AlCl3 and NiCl2, which perform well in halogenation reaction modified asphalt, perform poorly in acylation reaction, and the other catalysts are also unsatisfactory in improving the low-temperature flexibility of asphalt after modification.

[0064] Then, FeCl3, which performs relatively well and is cheap and readily available, was used as a catalyst to screen acylating agents, as shown in Table 5.

[0065] Table 5 Screening of acylating agents for acylation reaction

[0066]

[0067]

[0068] As shown in Table 5, using FeCl3 as a catalyst and trichloroacetyl chloride as an acylating agent can slightly improve the low-temperature flexibility of asphalt, and the low-temperature flexibility temperature is -1 to -2°C. However, for acylating agents such as p-nitrobenzoyl chloride, benzenesulfonyl chloride, o-nitrobenzenesulfonyl chloride, and trifluoroacetic anhydride, there is almost no improvement in the low-temperature flexibility of asphalt. Therefore, for aromatic acylation reactions, acetic anhydride as an acylating agent is the best for improving the low-temperature flexibility of asphalt.

[0069] Example 4: Alkylation reaction modified asphalt

[0070] Initial reaction conditions and steps:

[0071] Add 300g of base asphalt into a 1L metal barrel, then heat to 180°C, add Michael acceptor (30g, 10% by mass), then add catalyst (10mol% of Michael acceptor), control the speed of the shear mixer at 1500r / min, stir for 1h, discharge, shape and prepare samples.

[0072] First, acetic anhydride was used as the acylating agent to screen the catalyst, and then the low-temperature flexibility test of the modified asphalt was carried out (Table 6)

[0073] Table 6 Screening of alkylated anti-Michael acceptors

[0074]

[0075]

[0076] As shown in Table 6, when FeCl3 is used as a catalyst and Michael acceptors are screened, benzyl acrylate is used as a Michael acceptor, and the low-temperature flexibility temperature is -2 to -3°C. For Michael acceptors such as methyl acrylate, N-phenylmaleimide, acrylonitrile, maleic anhydride, N-chlorophthalimide, and 2-methylacrolein, there is almost no improvement in the low-temperature flexibility of asphalt. Therefore, for the screening of alkylation reaction catalysts, benzyl acrylate as a Michael acceptor is the best for improving the low-temperature flexibility of asphalt.

[0077] Then, Lewis acid catalysts were screened using benzyl acrylate, which performed relatively well, as the Michael acceptor, as shown in Table 7.

[0078] Table 7 Screening of alkylation reaction catalyst

[0079] Michael acceptor (10%) Catalyst (10 mol%) Low temperature flexibility(℃) Benzyl acrylate <![CDATA[FeCl3]]> -2～-3 Benzyl acrylate <![CDATA[AlCl3]]> -1～-2 Benzyl acrylate <![CDATA[NiBr2]]> 0～-1 Benzyl acrylate <![CDATA[CuCl2·2H2O]]> 0～-1 Benzyl acrylate <![CDATA[MnCl2]]> 0～-1 Benzyl acrylate <![CDATA[FeBr3]]> -1～-2 Benzyl acrylate <![CDATA[NiBr2]]> -1～-2 Benzyl acrylate <![CDATA[Ni(OAc)2]]> 0～-1

[0080] As shown in Table 7, using benzyl acrylate as the Michael acceptor and FeCl3 as the catalyst, the low-temperature flexibility of asphalt is slightly improved, and the low-temperature flexibility temperature is -2 to -3°C. For AlCl3, CuCl2·2H2O, MnCl2, NiBr2, FeBr3, NiBr2 and other catalysts, there is almost no improvement in the low-temperature flexibility of asphalt. Therefore, for the screening of alkylation reaction catalysts, FeCl3 as the catalyst is the best for improving the low-temperature flexibility of asphalt.

[0081] The above embodiments provide a detailed description of the present invention, the purpose of which is to enable persons familiar with the technology in this field to understand the contents of the present invention and implement them, and the protection scope of the present invention cannot be limited thereby. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for improving the anti-aging performance of asphalt by halogenation, aryl acylation and alkylation reaction, characterized in that: The following steps are involved: (1) Akg70# base asphalt is heated to 130°C to 180°C, and Bkg modifier and Cmol catalyst are added to obtain a mixture; A:B = (10-40): 1; C = (B / M)*(5%-10%), where M is the molecular weight of the added modifier; (2) heating and stirring the mixture of step (1), discharging, shaping and sampling after the reaction is completed to obtain modified asphalt.

2. The method of claim 1 for improving the anti-aging performance of asphalt by halogenation, aryl acylation and alkylation reaction, characterized in that: The modifier includes a halogenating agent, an aromatic acylating agent or a Michael acceptor; the halogenating agent includes NBS, NCS, DCH, TCCA, NCSac, NCP, DBH, PHP, DBI, TBCA, NBSac, NBP, NIS, NIP, N-fluorobisbenzenesulfonamide, trichloromelamine, sodium dichloroisocyanurate, carbon tetrabromide, dibromohydantoin or dichlorohydantoin; the aromatic acylating agent includes acetic anhydride, trichloroacetyl chloride, p-nitrobenzoyl chloride, o-nitrobenzenesulfonyl chloride, benzenesulfonyl chloride, trifluoroacetic anhydride, phthalic anhydride, phosphoric anhydride, permanganic anhydride, chloroacetyl chloride, thionyl chloride, dimethylformamide, sulfonamide or benzenesulfonamide; the Michael acceptor includes methyl acrylate, benzyl acrylate, N-phenylmaleimide, acrylonitrile, maleic anhydride, N-chlorophthalimide or 2-methylacrolein.

3. The method of claim 1 for improving the anti-aging performance of asphalt by halogenation, aryl acylation and alkylation reaction, characterized in that: The catalyst comprises a Lewis acid catalyst or a Bronsted acid catalyst, wherein the Lewis acid catalyst comprises AlCl3, FeCl3, NiCl2, CuCl2·2H2O, MgCl2, ZnCl2, MnCl2, MnCl2·4H2O, SnCl2, Al(NO3)3·9H2O, Ni(NO3)2, Zn(NO3)2·6H2O, Cu(NO3)2·3H2O, Cr(NO3)2, Co(NO 3)2, Cu(OAc)2·H2O, Pd(OAc)2, Ni(OAc)2, Cd(OAc)2·2H2O, Fe(acac)2, FeBr2, NiBr2, CuCO3, CuSO4, CuS·H2O, In(OTf)3, Sc(OTf)3, Ga(OTf)3, Yb(OTf)3, Zn(OTf)2 or Y(OTf)3; the Bronsted acid includes formic acid, acetic acid or p-toluenesulfonic acid.

4. The method of claim 1 for improving the anti-aging performance of asphalt by halogenation, aryl acylation and alkylation reaction, characterized in that: The heating temperature of step (2) is between 130°C and 180°C.

5. The method of claim 1 for improving the anti-aging performance of asphalt by halogenation, aryl acylation and alkylation reaction, characterized in that: The stirring speed of step (2) is controlled at 1000 r / min-1500 r / min.

6. The method of claim 1 for improving the anti-aging performance of modified asphalt by halogenation, aryl acylation and alkylation reaction, characterized in that: The stirring time of step (2) is controlled within 1 h to 2 h.

7. The method of claim 1 for improving the anti-aging performance of modified asphalt by halogenation, aryl acylation and alkylation reaction, characterized in that: The modifier is a halogenating agent, and when it is NBS, the catalyst used is FeCl3.

8. The method of claim 1 for improving the anti-aging performance of modified asphalt by halogenation, aryl acylation and alkylation reaction, characterized in that: The modifier is an aromatic acylating agent, and when it is acetic anhydride, the catalyst used is FeCl3, NiBr2, Ni(NO3)2 or CuS·H2O.

9. The method of claim 1 for improving the anti-aging performance of modified asphalt by halogenation, aryl acylation and alkylation reaction, characterized in that: When the modifier is a Michael acceptor and is benzyl acrylate, the catalyst used is FeCl3.

10. A modified asphalt obtained by the method according to any one of claims 1 to 9.

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