62 results about "Mole ratio" patented technology

The invention provides a feeding control method and device for an arsenic hydride reaction kettle, equipment and a storage medium, and belongs to the technical field of arsenic hydride reaction, and the method comprises the following steps: determining an initial feeding mode of raw materials at the initial reaction stage based on the volume of the reaction kettle and an expected reaction molar ratio; the raw materials comprise zinc arsenide and dilute sulphuric acid; the desired reaction molar ratio is the desired molar ratio between zinc arsenide and dilute sulphuric acid; in response to the situation that the pressure change rate in the reaction kettle is smaller than a preset change rate value, the initial feeding mode is switched into a constant-speed feeding mode of raw materials in the middle stage of reaction; in response to the condition that the generation rate of the arsenic hydride is lower than a preset generation rate value, switching the constant-speed feeding mode into a final feeding mode of raw materials at the end of the reaction; according to the arsenic hydride reaction kettle feeding control method and device, the equipment and the storage medium provided by the invention, the feeding opportunity and the feeding speed of the reaction kettle can be accurately grasped.

The application provides a hydrogen arsenide reaction kettle feeding control method and device, equipment and storage medium, and belongs to the technical field of hydrogen arsenide reaction. The method comprises the following steps: determining an initial feeding mode of raw materials in the initial stage of reaction based on the volume of the reaction kettle and an expected reaction molar ratio; the raw materials comprise zinc arsenide and dilute sulfuric acid; the expected reaction molar ratio is an expected molar ratio between the zinc arsenide and the dilute sulfuric acid; in response to a pressure change rate in the reaction kettle being less than a preset change rate value, switching the initial feeding mode to a uniform feeding mode of the raw materials in the middle stage of reaction; and in response to a generation rate of hydrogen arsenide being lower than a preset generation rate value, switching the uniform feeding mode to a final feeding mode of the raw materials in the late stage of reaction. The hydrogen arsenide reaction kettle feeding control method and device, equipment and storage medium provided by the application can accurately grasp the feeding time and feeding speed of the reaction kettle.

This invention relates to a selective gold-based oxidation catalyst, its preparation method, and its application; the catalyst comprises components represented by general formula (1): Au-Sc a / Si b Ce c X d O e In formula (1), a is the molar ratio of Sc to Au, with a value of 0.1 to 1.0; b is the molar ratio of Si to Au, with a value of 100 to 500; c is the molar ratio of Ce to Au, with a value of 1.0 to 30.0; d is the molar ratio of X to Au, with a value of 0.1 to 2.0; e is the number of oxygen atoms required to satisfy the oxidation states of each element in the active component; X is selected from at least one of Li, Na, K, Rb, and Cs. The catalyst of the present invention is used for selective oxidation, with high yield of target product and high conversion rate of raw materials. For example, it has the characteristics of high conversion rate of methacrolein and high yield of methyl methacrylate in the synthesis of alkyl acrylates.

A method for manufacturing solketal ((2,2-Dimethyl-1,3-dioxolan-4-yl)methanol) includes: (1) milling starting reagents, including at least: glycerol, a catalyst selected from a hard Lewis acid including at least one transition metal, and acetone, the molar ratio (glycerol):(acetone) being less than or equal to 0.8; preferably less than or equal to 0.7, at an ambient temperature greater than or equal to 50° C., preferably greater than or equal to 56° C., in a three-dimensional microbead mill in a liquid phase for a residence time less than or equal to 15 minutes, preferably less than or equal to 10 minutes, and in particular less than or equal to 5 minutes; (2) recovering, as output from the mill, a final composition including solketal and, where appropriate, one or more sub-products corresponding to the starting reagents that have not reacted and / or to 1,3-O-isopropylidene-glycerol, and (3) optionally, separating the solketal from the one or more sub-products.

The invention discloses a modified small-grain Y-type molecular sieve as well as a preparation method and application thereof. The total molar content of 0-NNN aluminum and 1-NNN aluminum in the modified small-grain Y-type molecular sieve is 89% or above, preferably 92% or above, based on the total molar weight of X-NNN aluminum; the molar ratio of the 0-NNN aluminum to the 1-NNN is 2.1 to 7.5, and preferably, the molar ratio is 2.3 to 6.0. The modified small-grain Y-type molecular sieve has the advantages that the content and proportion of 0-NNN aluminum and 1-NNN aluminum are high, the crystallinity is high, and the pore volume proportion of 4-8nm mesopores is large; when the modified small-grain Y-type molecular sieve is applied to a hydrocracking catalyst, the yield and quality of middle distillate can be improved.

An one component (1K) composition comprising: a) thermally-expandable thermoplastic microspheres; b) at least one epoxide compound; c) at least one compound which provides at least two amine hydrogens reactive toward epoxide groups; and, d) at least one accelerator, wherein the composition is characterized by a molar ratio of epoxide-reactive groups to epoxide groups from 0.6:1 to 1.2:1, preferably from 0.95: 1 to 1.1:1. The present disclosure envisages the use of this one component (1K) composition in providing an adhesive within a bonded structure upon curing of said composition under conditions in which the constituent microspheres retain their capacity to thermally expand.

The application discloses a continuous Saucy-Marbet ketonization reaction process of allyl alcohol compounds. Specifically provided is a preparation method of compound II, which comprises the following steps: reacting compound I and 2-methoxy propylene in the presence of an acid in a tubular reactor to generate compound II; and the acid is added in the following manner: in the first stage, the molar ratio of the acid to the compound I is 0.005-0.015; in the second stage, the molar ratio of the acid to the compound I is 0.006-0.020; and in the third stage, the molar ratio of the acid to the compound I is 0.009-0.025. The preparation method disclosed by the application has one or more of the following advantages: (1) high yield, (2) high purity, (3) few side reactions, (4) simple operation and (5) low cost.

The invention relates to the technical field of analytical chemistry and hydrometallurgy, in particular to a method for measuring coordination number of organic acid and RE < 3 + > by using a molar ratio method. The method comprises the following steps: S1, preparing a plurality of organic acid solutions of CY with different concentrations, preparing a RE3 + solution of CM, mixing the organic acid solutions and the RE3 + solution in an isovolumetric manner, adjusting the pH value, and carrying out a complexation reaction; s2, carrying out ultraviolet spectrophotometric measurement, determining the maximum absorption wavelength, and determining the absorbance A of the solutions after the complexation reaction under the maximum absorption wavelength; s3, drawing by taking the molar ratio n = [CY] / [CM] as a horizontal coordinate and the absorbance A as a vertical coordinate, and finding out an interval in which the absorbance linearly rises along with the increase of n and an interval in which the absorbance reaches a platform or the slope is obviously changed; linear fitting is conducted on the data points of the two intervals, two straight lines are obtained, and the value of an abscissa n corresponding to the intersection point of the two straight lines is the coordination ratio of the complex. The method is reliable in result, low in cost, easy to popularize, convenient and fast.

Provided is a method for producing an alkane, which performs a reaction at a relatively low reaction temperature and reaction pressure, suppresses carbon reduction with respect to an alcohol, and has excellent conversion rate and selectivity. A method for producing an alkane from an alcohol having 8-24 carbon atoms, said method comprising: a step in which the alcohol having 8-24 carbon atoms and hydrogen are reacted in the presence of a zeolite catalyst and a noble metal from Group 8-10 of the periodic table under the conditions of a reaction temperature of 160 DEG C or higher and a hydrogen pressure of 3 MPa or less in terms of gauge pressure; the zeolite catalyst is of an H-beta type or an H-ZSM-5 type, and the molar ratio (SiO2 / Al2O3) of silica (SiO2) to alumina (Al2O3) is 20-35.

A two component (2K) composition comprising: a first component comprising: a) at least one epoxide compound; and, a second component comprising: b) at least one compound which provides at least one epoxide-reactive group; c) at least one accelerator, wherein the composition further comprises: d) at least one particulate liquid-absorbent polymer, and wherein the composition is characterized by a molar ratio of epoxide groups to epoxide-reactive groups (ER) of from 0.6:1 to 1.2:1, for example from 0.9:1 to 1.1:1.

This application relates to a fluid water-in-oil emulsion comprising: A) at least one polyester, which is a reaction product of the following components (i), (ii) and (iii): (i) at least one polyglycerol-3; (ii) at least one dimer acid; and (iii) at least one fatty monocarboxylic acid having 8 to 30 carbon atoms, wherein the reacting components (i), (ii) and (iii) are in a molar ratio of 1 mole of polyglycerol-3, 0.5 to 1 mole of dimer acid, and 0.1 to less than 2.0 moles of fatty monocarboxylic acid; B) at least one continuous oil phase comprising: 1) at least one volatile hydrocarbon oil; and 2) optionally at least one non-volatile oil; and C) at least one aqueous phase dispersed in the oil phase, wherein the liquid component of the aqueous phase accounts for at least 50% by weight of the total weight of the composition; and D) At least one nonionic surfactant with an HLB of less than 8.0, the chemical structure of which is generated by the reaction of at least one polyhydroxystearic acid and / or at least one polyricinoleic acid with a polyol containing at least two alcohol functional groups; the weight ratio of nonionic surfactant D) to polyester A) is greater than or equal to 0.9 and preferably greater than or equal to 1.0.

The present invention is composition comprising a mixture of a mica and a TR-DRR resin, where each R is independently phenyl or methyl, wherein the mole-to-mole ratio of DRR units to TR units is in the range of from 30:70 to 80:20; and wherein the weight-to-weight ratio of mica to the TR-DRR resin is in the range of 20:80 to 80:20. The composition of the present invention is useful as a coating for a substrate, wherein the coating exhibits good adhesion, and crack-resistance when subjected to high temperatures for several weeks.

The application discloses a method for regulating bubble size in a high-temperature molten salt bubbling tower, comprising the following steps: according to the diameter range of the target bubble required by the bubbling tower, a single-hole bubbling experimental device is built by selecting a bubble distributor with a corresponding characteristic aperture; according to the component of the molten salt required by the bubbling tower, a database of the relationship between the molar ratio of each chemical component of the molten salt and the physical properties is established; in the single-hole bubbling experimental device, a regulation mode is selected according to the size of the characteristic aperture of the bubble distributor, the adjustable range of the bubble diameter is adjusted to the diameter range of the target bubble required by the bubbling tower; and the obtained regulation mode is applied to the bubbling tower; the application can reveal a comprehensive solution of the synergistic mechanism among multiple parameters, so as to realize accurate and predictable control of the bubble size from microns to millimeters, and solve the technical problems from laboratory research to industrial device amplification.

The present invention relates to a process for preparing a polyester of glycerol and a dicarboxylic acid, the process comprising: (a) contacting monomers comprising at least glycerol and dicarboxylic acid in the presence of water in an inert atmosphere at a temperature of less than 100 DEG C wherein the molar ratio of glycerol / dicarboxylic acid ranges from 0.5 / 1 to 10 / 1; (b) carrying out esterification in an inert atmosphere at a temperature higher than 110 DEG C; (c) at a temperature higher than 110 DEG C, vacuumizing the reaction medium to a pressure lower than 100 mbar; (d) maintaining a vacuum and a temperature above 110 DEG C to carry out polycondensation, said process comprising: at the end of the esterification of step (b), before or after the evacuation of step (c), introducing a polycondensation catalyst in an amount of less than or equal to 5000 ppm with respect to the total weight of monomers, said catalyst being a tin-based food grade catalyst, the organic tin compounds are selected from organic tin compounds containing carboxyl functional groups (-C (O) OH), organic tin compounds containing functional groups (-Sn (O) OH) and mono-butyltin tris (2-ethylhexanoate). The present invention relates to a process for synthesizing glycerol polyesters having a residual monomer content of less than 5% by weight, based on the weight of the polymer, a high number average molar mass Mn of greater than 2500 g / mol, a dispersity of less than or equal to 10 and a 1, 2, 3-triacylglyceride unit content of less than 15 mol% with respect to all units of the polymer, in particular to the synthesis of glycerol polyesters having a residual monomer content of less than 5% by weight, based on the weight of the polymer, a high number average molar mass Mn of greater than 2500 g / mol.

The present invention discloses an SCM-38 molecular sieve and a preparation method thereof. The SCM-38 molecular sieve is a new type of molecular sieve, and its chemical composition includes, in molar ratio: SiO2: Al2O3: P2O5 = 0-0.1: 0.8-1.5: 1, and the XRD pattern of the SCM-38 molecular sieve includes X-ray diffraction peaks at 2θ of 7.20 ± 0.1, 10.81 ± 0.1, 11.60 ± 0.1, 14.32 ± 0.1, 21.39 ± 0.1, 21.83 ± 0.1, 27.31 ± 0.1, and 28.72 ± 0.1, wherein 2θ is 7.20 ± 0.1 as the strongest peak. The SCM-38 molecular sieve provided by the present invention can be used in adsorbents or catalysts.

The invention provides an SCM-44 molecular sieve as well as a preparation method and application thereof. The chemical composition of the SCM-44 molecular sieve is xSiO2.y GeO2, the molar ratio of SiO2 to GeO2 is x / y, x / y is larger than or equal to 40, and preferably x / y is larger than or equal to 50. The framework of the SCM-44 molecular sieve contains an Si element and other optional elements, and the SCM-44 molecular sieve has flaky morphology, high specific surface area, large micropore volume and excellent adsorption and catalytic performance.

This inorganic compound includes M, O, and F, in which M is one or more kinds of transition metal elements, when defining a molar ratio of O as “b” and defining a molar ratio of F as “c”, (b / c) is 0.60 or more and 2.30 or less, and a half-value width of a diffraction peak of a (110) plane obtained by X-ray diffraction analysis is 0.60° or less. Also, the inorganic compound includes M, O, and F, in which M is one or more kinds of transition metal elements, when defining a molar ratio of O as “b” and defining a molar ratio of F as “c”, (b / c) is 1.50 or less, and a half-value width of a diffraction peak of a (110) plane obtained by X-ray diffraction analysis is 0.45° or more.

To provide a method for producing propylene capable of producing propylene with a comparatively excellent yield.SOLUTION: A method for producing propylene pertaining to the present invention includes: a reaction process A of obtaining a crude product (A) from a raw material including ethanol in the presence of a catalyst (A); and a reaction process B of obtaining a crude product (B) from the crude product (A) in the presence of a catalyst (B), where compositions of the catalyst (A) and the catalyst (B) are mutually different, the catalyst (A) includes at least two metals M and N selected from the group consisting of zirconium or the like, the mole ratio of the metal M to the metal N is less than 100, and the amount of an acid sites of the catalyst (B) is 50 μ mol / g or more.SELECTED DRAWING: None

A calcine containing γ-2CaO·SiO2, characterized in that it satisfies the following conditions of a) to c). a) C' / S' (molar ratio) represented by {[CaO]-4[Fe2O3]} / [SiO2] is 1.90 to 2.10. b) Fe2O3 / Al2O3 (molar ratio) is 0.90 to 1.10. c) Fe2O3 is 20.00 mass% or less.

The invention relates to a temperature-variable load-variable carbon deposition-resistant magnesium nitride-based carrier catalyst, and particularly relates to the technical field of catalysts. The catalyst is composed of a porous Mg3N2 carrier, an active component and an auxiliary agent. The specific surface area of the carrier is 30-150m < 2 > / g, and the pore diameter is in bimodal distribution: small pores of 5-20nm are enriched with active components, and large pores of 30-50nm are spatially isolated; the active component is at least one of Ru / Fe / Co and is dispersed in the form of particles with the particle size of 2-15nm; the auxiliary agent is at least one of K / Cs / Ba / La oxides; the distribution density gradient of the active components on the surface of the carrier is 1.5-3.0 times, and the axial concentration gradient is 0.05-0.2 wt% / mm. The preparation method comprises the following steps: roasting Mg (OH) 2 in NH3 / N2 at 600-800 DEG C to prepare the carrier; polyethylene glycol-6000 which is 1.5 times of the total molar weight of the active component and the auxiliary metal cations is used as a structure-directing agent, and pulse impregnation loading is carried out; gradient thermal synthesis is carried out (300 DEG C / 1h, 600 DEG C / 2h and 800 DEG C / 3h). During application, the reaction pressure is 5-30 MPa, the temperature reference is 400-500 DEG C and sine fluctuation is + / -20-50 DEG C (the period is 10-60 min), and the H2 / N2 molar ratio is switched over + / -0.5 every 30-120 min. The catalyst enables the carbon deposition amount to be 1t; the pressure difference rises 1t when the weight is 1.5 wt%; the pressure is 0.3 MPa, and the service life is gt; the time is 500 hours.

The application discloses a phosphorus-modified beta molecular sieve, characterized in that, after being treated under the condition of 800 DEG C, 17 hours and 100% water vapor atmosphere, the beta molecular sieve has the following characteristics: 29 The molar ratio of silica / alumina of the framework measured by Si MAS NMR is ≤40, 31 The ratio of the characteristic peak area of the chemical shift-17±3 resonance signal to the characteristic peak area of the chemical shift-30±5 resonance signal measured by P MAS NMR is ≥0.70.

The invention discloses an alicyclic low polycarbonate and application and a preparation method thereof, and the preparation method comprises the following steps: adding an alicyclic binary hydroxyl compound and a carbonation reagent into a reaction kettle, carrying out condensation polymerization on the system under the action of a mixed catalyst, and continuously removing reaction byproducts; in the reaction process, the alicyclic low polycarbonate is obtained by controlling the feeding molar ratio of reactants, the reaction time and the type proportion of the mixed catalyst, and the molar ratio of the alicyclic binary hydroxyl compound to the carbonation reagent is (0.98-1.05): 1; the reaction time is 3-6 hours; the ratio of the mixed catalyst is (2-4): 1. According to the invention, the molecular weight is stably controlled within the optimal optical function range of 900-1800 in the low polycarbonate range, and the molecular weight is stable, the molecular weight distribution is controllable and the repeatability among batches is good through the synergistic effect of the feed ratio, the reaction time and the type proportion of the mixed catalyst.

To provide a faujasite-type zeolite having a reduced proportion of Bronsted acids with high acid strength.SOLUTION: A faujasite-type zeolite has: a molar ratio of SiO2 / Al2O3 in a range of 40 or more and 200 or less; a crystallinity in a range of 0.20 or more and 1.00 or less; a Bronsted acid amount in a range of 20 μmol / g or more and 400 μmol / g or less, as measured by pyridine-adsorbed FT-IR after evacuation at 150°C; and a proportion of the Bronsted acid amount, measured after evacuation at 450°C, of less than 65%, relative to the Bronsted acid amount measured after evacuation at 150°C.SELECTED DRAWING: None

Provided is an inexpensive oxygen storage material having an excellent oxygen release performance at low temperature. One aspect of the present disclosure relates to a composite oxide having a composition represented by a general formula Ce2-w-x′AwA′x′B1-y′-zB′y′B″zO6-w / 2-x′-y′ / 2-z. In the formula, A is one or more elements selected from rare-earth metal elements excluding Ce, A′ is one or more elements selected from alkaline earth metal elements, B is one or more elements selected from the group consisting of Ti and Group 14 elements, B′ is one or more elements selected from the group consisting of Group 13 elements, B″ is one or more elements selected from the group consisting of Group 12 elements, 2−w−x′, w, x′, 1−y′−z, y′, z, and 6−w / 2−x′−y′ / 2−z are mole ratios of Ce, A, A′, B, B′, B″, and O, respectively when B+B′+B″ is assumed to be 1, w, x′, y′, and z satisfy 0≤w<2, 0≤x′<0.5, 0≤y′≤1, 0≤z≤0.5, respectively, and w+x′ satisfies 0≤w+x′<2, and y′+z satisfies 0≤y′+z≤1.

A method for producing a Guerbet alcohol in which a starting material alcohol having 8-22 carbon atoms is reacted in the presence of a catalyst (A) containing a first component and a second component, the molar ratio of the second component to the first component, i.e., second component / first component, being 0.0001-0.005. A first component: copper; the second component is one element selected from the group consisting of Groups 9 to 13 belonging to cycles 4 to 6 of the periodic table and not copper.

The present disclosure: (I) a first component comprising: a) Formula (AI): TIFF2025530806000013.tif3776[in the formula, R e is a C1-C6 alkyl group; R f Epoxide-substituted C1-C 12 Alkyl groups, C3-C 18 Cycloalkyl groups or C2-C 18 an alkoxyalkyl group; R g is H or a C1-C6 alkyl group; R h is a C1-C6 alkyl group; i is an integer greater than or equal to 1; and j is an integer greater than or equal to 1. at least one epoxy silane oligomer represented by the formula: b) at least one polyepoxide compound having at least three epoxide groups per molecule; and optionally, c) at least one compound selected from the group consisting of monoepoxide compounds and diepoxide compounds; wherein the compounds of parts b) and c) do not satisfy formula (AI); (II) a second component comprising: d) a curing agent consisting of at least two compounds having at least two epoxide-reactive groups per molecule, characterized in that the curing agent comprises at least one Mannich base and at least one cycloaliphatic amine; A two-component (2K) composition comprising: The two-component (2K) composition further comprises e) Core-shell rubber particles and Furthermore, the present invention relates to a two-component (2K) composition characterized in that the molar ratio of epoxide-reactive groups to epoxide groups is 0.95:1 to 1.5:1.

To provide a recycling method for separating and recovering a material part (a1) from a treating object (a) which is a composite material composed of at least one or more chemical parts (a2) and at least one or more material parts (a2).SOLUTION: By adjusting the molar ratio X / Y to 0.002 or more and the molar ratio Z / Y to 0.3 or more and 30 or less in the treatment liquid containing the catalyst (b), the nucleophilic agent (c), and the solvent (d) (where X+Y+Z=100 when the respective molar fractions are Xmol%, Ymol%, and Zmol%), the urethane bond contained in the treatment target (a) can be decomposed at a temperature lower than that in the related art, particularly at a temperature of lower than 100°C, and the material part (a2) remaining without being decomposed can be separated and recovered.SELECTED DRAWING: Figure 1

The application provides a process parameter determination method of a hydrogen-based reducing gas preparation process based on carbon precipitation control, which comprises the following steps: calculating the degrees of freedom of a hydrogen-based reducing gas preparation process system under a critical carbon precipitation balance condition; determining a physical quantity parameter that can be independently changed and has a strength property in the hydrogen-based reducing gas preparation process system according to the degrees of freedom under the critical carbon precipitation balance condition, and obtaining a balance gas phase composition function under the critical carbon precipitation balance condition; drawing an H-C-O two-dimensional graph with the mole ratio of H and C as the ordinate and the mole ratio between O and C as the abscissa; using the balance gas phase composition function to represent the O / C mol ratio and the H / C mol ratio in the hydrogen-based reducing gas preparation process system, and obtaining a drawing calculation formula of a critical carbon precipitation point in the H-C-O two-dimensional graph; assigning values to the physical quantity parameters, drawing a critical carbon precipitation curve in the H-C-O two-dimensional graph according to the drawing calculation formula of the critical carbon precipitation point based on the assigned physical quantity parameters, and determining the process parameters of the hydrogen-based reducing gas preparation process based on carbon precipitation control according to the critical carbon precipitation curve.

This invention relates to the field of catalyst technology, and discloses an iron-based catalyst, its preparation method, and its application. The catalyst has the structure shown in the following formula: FeA a M b Q c O x Wherein, A is Cu and / or Zr; M is selected from at least one Group IIA metal element; Q is selected from at least one lanthanide element; a, b, and c are the molar ratios of A, M, and Q to Fe, respectively, where a = 0.1–0.6; b = 0.1–0.4; c = 0.05–0.2; and x is the total number of oxygen atoms required to satisfy the valence of each element in the active component. The iron-based catalyst, through the specific combination of active metal components and their contents, exhibits high CO conversion rate and low-carbon olefin selectivity.

The present disclosure relates to a particle having a core-shell structure, wherein the core comprises a perovskite compound CsPbX3, and the shell comprises Csn-1PbnX3n+12− and at least one organic ammonium cation R1R2R3R4N+, wherein n is 1 or 2; R1 is selected from the group consisting of optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, optionally substituted arylalkyl, and optionally substituted heteroaryl; R2, R3, and R4 are each independently selected from the group consisting of —H, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, optionally substituted arylalkyl, and optionally substituted heteroaryl; and X is a halide. The present disclosure also relates to a method of passivating a perovskite compound CsPbX3, the method comprising the step of: adding an organic ammonium halide R1R2R3R4NY to the CsPbX3 at a molar ratio of R1R2R3R4NY:CsPbX3 of about 500:1 to about 60000:1 to form a mixture, wherein R1 is selected from the group consisting of optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, optionally substituted arylalkyl, and optionally substituted heteroaryl; R2, R3, and R4 are each independently selected from the group consisting of —H, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, optionally substituted arylalkyl, and optionally substituted heteroaryl; and X and Y are independently a halide.