Synthesis process for neutral polymer bonding agents

Abstract

This disclosure relates to a process for the synthesis of a compound of formula (I): (I) wherein w, x, y, and z are as defined in the description. The process includes the reaction of a compound of formula (II): (II) with carbonyldiimidazole, and the reaction of the resulting compound with propargylamine.

Description

Title of the invention: Process for synthesizing neutral polymer bonding agents Technical field of the invention This disclosure relates to the field of energetic materials, and more specifically to a process for synthesizing intermediate compounds useful in the preparation of said materials. State of the art Composite solid propellants have a wide range of applications, particularly in the propulsion sector. These propellants are typically prepared from a mixture of fuel, oxidizer, and polymer binder. A small amount of binding agent may be incorporated to ensure the mechanical properties of these materials. "NPBA" (Neutral Polymeric Binding Agents) type binding agents are described in US patent 4915755, for example, the polymer with the formula: CN C»O OCHj QCHaŒîOH in which x' equals 1, y' is in the range 0-0.5 and z' is in the range 0.1-0.5. More recently, Zhou et al. (Iranian Polymer Journal, vol. 28, no. 11, pp. 943-955, 2019) described the synthesis of NPBA from toluene diisocyanate and propynol ethoxylate. However, the use of diisocyanates is not desirable due to the hazardous nature of these products and their processing. In this context, the inventors set themselves the specification of the synthesis of neutral polymer bonding agents which comply with REACH regulations and which are compatible with use in energy materials. Summary of the invention This disclosure relates to a process for the synthesis of a compound of formula (I):

[0007] in which x=l;0 <w<l;0<y<let0<z<l;

[0008] the process comprising:

[0009] a) the reaction of a compound of formula (II):

[0010] in which w, x, y and z are such as defined above for formula (I),

[0011] with an excess of carbonyldiimidazole, possibly in the presence of a solvent;

[0012] b) the reaction of the compound obtained in step a) with an excess of propargylamine, optionally in the presence of a solvent.

[0013] This disclosure also relates to compounds of formula (I) that may be obtained by said process.

[0014] Description of the invention

[0015] In the context of this disclosure, the expression "between x and y" should be interpreted as including the bounds of the range under consideration (i.e., x and y).

[0016] The different embodiments described here can be combined.

[0017] In one aspect, the present disclosure relates to a process for synthesizing a compound of formula (I):

[0018] in which x=l;0 <w<l;0<y<let0<z<l;le procédé comprenant :

[0019] a) the reaction of a compound of formula (II):

[0020] in which w, x, y and z are such as defined above for formula (I),

[0021] with an excess of carbonyldiimidazole, possibly in the presence of a solvent;

[0022] b) the reaction of the compound obtained in step a) with an excess of propargylamine, optionally in the presence of a solvent.

[0023] Step a) is carried out in the presence of an excess of carbonyldiimidazole. By "excess of carbonyldiimidazole" is meant an amount between about 1.1 and about 6 equivalents.

[0024] Compounds of formula (II) can be obtained for example as described in US patent 4915755.

[0025] The compound obtained at the end of step a) is an "intermediate" compound with the formula:

[0026] in which w, x, y and z are such as defined above for formula (I), compound which is used as such for the implementation of step b).

[0027] Step b) is carried out in the presence of an excess of propargylamine. By "excess of propargylamine" is meant an amount between about 1.5 and about 6 equivalents.

[0028] In some embodiments, step a) is carried out at a temperature between ambient temperature and about 40°C, advantageously at a temperature between ambient temperature and about 30°C.

[0029] In some embodiments, the duration of step a) is between about 15 minutes and about 10 hours, advantageously between about 15 minutes and about 3 hours.

[0030] In some embodiments, step b) is carried out at a temperature between ambient temperature and about 40°C, advantageously at a temperature between ambient temperature and about 30°C. In some embodiments, the duration of step b) is between about 1h and about 48h, advantageously between 1h and about 24h.

[0031] In some embodiments, step a) is carried out in the presence of a solvent. In practice, a common organic solvent can be used, with the exception of nucleophilic solvents. Advantageously, the solvent can be chosen from methylene chloride, chloroform, 1,2-dichloroethane, and ethyl acetate.

[0032] In some embodiments, step b) is carried out in the presence of a solvent. In practice, a common organic solvent can be used, with the exception of nucleophilic solvents. Advantageously, the solvent can be chosen from methylene chloride, chloroform, 1,2-dichloroethane, and ethyl acetate.

[0033] In some embodiments, the solvent used in step a) and the solvent used in step b) are identical.

[0034] The process according to this disclosure has the following advantages:

[0035] - it is a "one-pot" synthesis;

[0036] - it gives quantitative returns;

[0037] - it uses reagents that are not very toxic and inexpensive;

[0038] - it allows easy purification of the final product.

[0039] In another respect, the present disclosure relates to compounds of formula (I) capable of being obtained by the process described above. These compounds are useful as neutral polymer bonding agents for the preparation of energetic materials such as composite solid propellants.

[0040] The invention will be better understood with the aid of the following illustrative example. In this example, the number-average (Mn) and mass-average (Mp) molar mass of the compound of formula (I) was determined by size-exclusion chromatography (SEC) using the following apparatus: - Equipment: Agilent Infinity 1260 thermostatically controlled at 70°C; - Detection: refractometry; - Eluent: Dimethyl sulfoxide, l,0ml / min; - Standard: Polymethyl methacrylate.

[0041] The polydispersity D of the compound of formula (I) is equal to the ratio Mp / Mn.

[0042] The compound of formula (I) was further characterized by NMR using a Bruker AC-400 device. Abbreviations

[0043] AIBN = azobisisobutyronitrile

[0044] CDI = carbonyldiimidazole

[0045] DCM = dichloromethane Example 1

[0046] Synthesis of a compound with the formula:

[0047] in which x = 1; y = 0.3; z = 0.2; w = 0.1

[0048] A 100 mL three-necked flask is equipped with a thermometer, a condenser, and a mechanical stirrer (300 rpm). It was then filled with 6 mL of acetone and placed in a water bath at room temperature. Acrylonitrile (4 mL, 60.3 mmols), n-butyl acrylate (2.58 mL, 18.1 mmols), 2-hydroxyethyl acrylate (1.39 mL, 12.1 mmols), N-vinylpyrrolidone (640 pL, 6.0 mmols), and mercaptoethanol (240 pL, 3.38 mmols) were added in portions using syringes. AIBN (206.38 mg, 1.26 mmols, 1.3 mol%) was then added, and the residues were rinsed with An additional 1 mL of acetone was added. The water bath temperature was then set to 64°C. The reaction continued for 6 hours at 60°C, after which 20 mL of methanol was added to stop the reaction. The mixture was then collected with acetone and completely evaporated under reduced pressure to retain only the copolymer. This copolymer was then dried overnight under deep vacuum (102 mbar) at room temperature. A yellow solid (6.88 g, 85%) was obtained.

[0049] 1 H NMR (acetone d6, 400 MHz, 21°C): ô (ppm) = 4.23 (s(br), -0ŒGCH20H), 4.14 (s(br), -OCHÆHoCHoCH j, 3.78 (s(br), -0CH2ŒG0H), 3.58 - 2.47 (m, CH chain 2.45 - 1.72 (m, CH2chalnemaine), 1.58 (s(br), -OCH2ŒGCH2CH3), 1.35 (s(br), -OCH2CH2Œ2CH3), 0.88 (s(br), -OCH2CH2CH2CH.;).

[0050] ATR-FTIR: v (cm1) = 3505 (w(b)), 2959 (m), 2935 (m), 2874(w), 2242(w), 1725(s), 1670(m), 1452(m), 1267(m), 1226(m), 1166(s), 1067(m), 936(w), 891(w), 842(w), 739(w), 652(w).

[0051] SEC (DMSO, Refractive index, PMMA calibration): Mp = 10,600 g.mol1; Mn = 25,400 g.mol1; D = 2.4. Example 2

[0052] Synthesis of a compound with the formula:

[0053] in which x = 1, y = 0.3, z = 0.2 and w = 0.1.

[0054] A 50 mL three-necked flask is equipped with a thermometer, a condenser and with magnetic stirring (300 rpm). It was then charged with 10 mL of dichloromethane and immersed in a water bath at room temperature and 1 g of a binding agent with the following formula:

[0055] in which x = 1, y = 0.3, z = 0.2, and w = 0.1. CDI (365.88 mg; 2.26 mmol; 1.5 equivalents) was then added in one portion, and the reaction continued at room temperature for 3 h. Propargylamine (300 pL; 4.72 mmol; 3 equivalents) was then added in one portion, and the reaction continued at room temperature for 18 h. At this stage, a proton NMR of the medium The reaction showed complete conversion. The reaction medium was diluted in 40

[0056] mL of dichloromethane was added, and the organic phase was then washed with 3 portions of 50 mL of distilled water. It was then dried over magnesium sulfate and evaporated under reduced pressure to recover a yellow solid (1.31 g; Quantitative). 1 H NMR (acetone d6, 400 MHz, 21°C): ô (ppm) = 6.69 (s(br), NH), 4.33 (s(br), -OC H 2CH 2O), 4.15 (s(br), -OŒ2CH2CH2CH3), 3.95 (s(br), -C^2C=CH), 3.58 - 2.53 (m.CH chain pnnd^e), 2.68 (s(br), -CH2C=CH), 2.40 - 1.75 (m, CH2 chaîne principale) ? 1.66 (s(br), -OCH2Œ2CH2CH3), 1.42 (s(br), -OCH2CH2Œ2CH3), 0.95 (s(br), -OCH2CH2

[0057]

[0058] CH2CH.p. ATR-FTIR : v (cm1) = 3368 (w), 3282 (w), 2960 (m), 2931 (m), 2874(w), 2242(w), 1720(s), 1677(m), 1520(m), 1452(m), 1239(s), 1168(s), 1058(m), 944(w), 776(w), 652(m). SEC (DMSO, Indice de réfraction, calibration PMMA): Mp = 12 600 g.mol1; Mn = 7 000 g.mol *;D= 1,8.

Claims

Demands

1. Synthesis process for a compound of formula (I): in which x=l;0 <w<l;0<y<let0<z<l; the process comprising: a) the reaction of a compound of formula (II): q (H)

2.

3.

4.

5.

6.

7. in which w, x, y and z are such as defined above for formula (I), with an excess of carbonyldiimidazole, possibly in the presence of a solvent; b) the reaction of the compound obtained in step a) with an excess of propargylamine, advantageously in the presence of a solvent. A process according to claim 1, wherein step a) is carried out at a temperature between ambient temperature and 40°C. A method according to claim 1 or claim 2, wherein the duration of step a) is between 15 minutes and 100. A method according to any one of claims 1 to 3, wherein step a) is carried out in the presence of a solvent. A method according to any one of claims 1 to 4, wherein step b) is carried out at a temperature between ambient temperature and 40°C. A method according to any one of claims 1 to 5, wherein the duration of step b) is between 1h and 48h. A method according to any one of claims 1 to 6, wherein step b) is carried out in the presence of a solvent.

8.

9. A method according to any one of claims 1 to 7, wherein the solvent used in step a) and the solvent used in step b) are identical. Compound of formula (I) obtained by the process according to any one of claims 1 to 8: formula in which x=l;0 <w<l;0<y<let0<z<l.