Methods and compositions for preventing dimethyl trisulfide degradation

Abstract

This disclosure provides methods and compositions for inhibiting the degradation of dimethyl trisulfide (DMTS) in solution. The concentrated composition comprises DMTS and a polar inorganic or organic solvent. The composition can be stored in a container at 54°C for at least 2 weeks or at room temperature for at least 1 year, with less than 50% of the DMTS degrading. The concentrated composition can be diluted for use and combined with other components to form various solutions.

Description

[0001] Cross-reference to related applications

[0002] This application was filed on June 4, 2019 as a PCT international application and claims priority to U.S. Provisional Application No. 62 / 680,117, filed on June 4, 2018, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to methods and compositions for preventing the degradation of dimethyl trisulfide (DMTS) in solution. Background Technology

[0004] Dimethyl trisulfide (DMTS) is a volatile sulfur compound. DMTS has an odor associated with cooked onions, Limburger cheese, and aged beer. DMTS is produced by the decomposition of bacteria and mammals. The odor of DMTS attracts a variety of insects and flies.

[0005] DMTS has been identified as a component of insect pheromones. Specifically, DMTS attracts blood-feeding insects, such as bed bugs. DMTS can be combined with other compounds to enhance its attractive properties. In some cases, DMTS is combined with MDEA (methyldiethanolamine) or other amines to attract insects, such as bed bugs, more effectively. Once an insect is attracted, it can be captured or killed.

[0006] Storing DMTS in solution presents challenges. Existing DMTS solutions, whether alone or in combination with MDEA, are unstable when dissolved in water. Over time, DMTS decomposes and disappears from the solution. Improved methods for storing DMTS in solution are needed.

[0007] This disclosure arose in this context. This document provides techniques and improvements. Summary of the Invention

[0008] In summary, this disclosure relates to methods and compositions for reducing the degradation of dimethyl trisulfide (DMTS) in solution. Various aspects are described in this disclosure, including but not limited to the following.

[0009] On one hand, the single-phase concentrate composition comprises at least 10 ppm of DMTS and at least 10 wt% of a polar organic solvent. The DMTS degrades by no more than 40% within one year of storage, and the concentrate composition is phase-stable in the container.

[0010] On the other hand, the single-phase concentrate composition comprises at least 10 ppm of DMTS and an amine and at least 80 wt% of a polar organic solvent. The DMTS and amine degrade by no more than 40% within one year of storage, and the concentrate composition is phase-stable in the container.

[0011] On the other hand, the single-phase composition includes DMTS and has a pH of 9 or less. When the pH is 9 or less, the composition degrades by no more than 40% within one year of storage, and is phase-stable in the container when the carrier is water, a polar organic solvent, or both.

[0012] On the other hand, the single-phase composition comprises DMTS and an amine and has a pH of 4 or lower. When the pH is 4 or lower, the composition degrades by no more than 40% within one year of storage and is phase-stable in the container when the carrier is water, a polar organic solvent, or both.

[0013] On the other hand, the containers used to contain the composition are essentially free of materials that would cause DMTS degradation.

[0014] On the other hand, a method for preparing an insect pheromone solution includes diluting the concentrate composition with water, a polar organic solvent, or both.

[0015] This synopsis is provided to introduce a series of concepts in a simplified form, which will be further described in the detailed description below. This synopsis is not intended to identify key or essential features of the claimed object, nor is it intended to limit the scope of the claimed object. Attached Figure Description

[0016] Figure 1 This is a line graph showing the recycling of DMTS over time with or without MDEA;

[0017] Figure 2 This is a line graph showing the recovery of DMTS over time under various solvent conditions;

[0018] Figure 3 It compares the concentrations of DMTS and MDEA and shows a line graph of DMTS recovery over time;

[0019] Figure 4 It compares the concentrations of DMTS and propylene glycol, and shows a line graph of DMTS recovery over time;

[0020] Figure 5 It is a line graph comparing the fluorination levels of HDPE containers and showing the recycling of DMTS over time;

[0021] Figure 6 It is a line graph comparing glass and fluorinated HDPE containers, showing the recycling of DMTS over time;

[0022] Figure 7 It is a line graph comparing storage containers and solvents, showing the recovery of DMTS over time;

[0023] Figure 8 This is a line graph comparing the recovery of DMTS over time with 100% polar organic solvents;

[0024] Figure 9 This is a line graph comparing solvents with different concentrations of propylene glycol in water, showing the recovery of DMTS over time;

[0025] Figure 10 This is a line graph comparing solvents with different concentrations of propylene glycol in water, showing the recovery of DMTS over time;

[0026] Figure 11 It compares solvents with different concentrations of polar organic solvents in water, and shows a line graph of DMTS recovery over time; and

[0027] Figure 12 This is a line graph comparing solvents with different concentrations of propylene glycol in water, showing the recovery of DMTS over time. Detailed Implementation

[0028] Various embodiments will be described in detail. Reference to the various embodiments does not limit the scope of the appended claims. Furthermore, any examples set forth in this specification are not intended to be limiting and merely illustrate some of the many possible embodiments of the appended claims.

[0029] This disclosure relates to compositions comprising dimethyl trisulfide (DMTS). The compositions and containers provided herein create stable storage conditions for solutions comprising DMTS. DMTS is stored in solutions containing polar inorganic and / or organic solvents, optionally in containers that do not promote the degradation of DMTS.

[0030] The EPA's accelerated stability guidelines state that storing at 54°C for two weeks is equivalent to storing at room temperature for one year. The compositions and methods described herein provide solutions containing DMTS that are stable for at least one year.

[0031] In some aspects, the DMTS in the solution degrades by no more than 60% over a one-year period. In some embodiments, the DMTS degrades by less than 50%, less than 40%, or less than 30% during a one-year storage period. In some formulations, a DMTS solution is provided in which less than 20% of the DMTS degrades over a one-year period. In some cases, less than 10% or less than 5% of the DMTS in the composition degrades.

[0032] Previous studies have found that DMTS degrades more rapidly under certain conditions. For example, DMTS degrades faster when stored in non-fluorinated HDPE (plastic) containers compared to glass containers. DMTS also degrades faster when combined with MDEA than when it is in a solution alone. Various solvents and pH levels in solutions containing DMTS were investigated. Further analysis of solvent, pH, and container material variables was conducted, as described in the examples below, to determine improved compositions and storage methods for DMTS solutions that prevent DMTS degradation.

[0033] Composition

[0034] The compositions used in this disclosure provide stable storage for DMTS. When packaged in suitable containers, the compositions show reduced degradation after storage at 54°C for 2 weeks compared to existing solutions. These storage conditions simulate storage at room temperature for one year, according to EPA guidelines. The compositions according to this disclosure are stored as concentrates for later dilution before use, or as ready-to-use solutions that do not require further dilution before use. The concentrate compositions can be diluted with any suitable solvent. In some embodiments, the concentrate compositions are diluted with water to produce a use solution. In some cases, the use solution including DMTS can be combined with one or more other components to produce insect pheromone solutions and insecticide solutions.

[0035] The compositions according to this disclosure include at least DMTS and a diluent, which may be a polar inorganic solvent (e.g., water) or a polar organic solvent. Other components may include amines and other functional ingredients. In some embodiments, water is limited to or excluded from the concentrate composition.

[0036] dimethyl trisulfide

[0037] Dimethyl trisulfide (DMTS) can be used as an insect attractant or pesticide. DMTS is hydrophobic and poorly soluble in water.

[0038] The concentrate compositions disclosed herein comprise at least 10 ppm of DMTS. In some aspects, the concentrate compositions may comprise at least 20 ppm or at least 30 ppm of DMTS. The concentrate compositions may comprise at least 50 ppm, at least 100 ppm, or at least 300 ppm of DMTS. In some embodiments, the concentrate compositions according to the present disclosure comprise no more than 30,000 ppm of DMTS. In some aspects, the concentrate compositions comprise no more than 10,000 ppm of DMTS, no more than 6,000 ppm of DMTS, or no more than 3,000 ppm of DMTS. In some aspects, the concentrate compositions comprise from 30 ppm to 10,000 ppm of DMTS. Some concentrate compositions comprise from 100 ppm to 3,000 ppm or from 300 ppm to 1,000 ppm of DMTS.

[0039] The concentrate composition can be diluted to form an admixture or solution. The diluted admixture may include at least 0.3 ppm or at least 0.5 ppm of DMTS. In some aspects, the admixture includes at least 0.7 ppm, at least 0.9 ppm, or at least 1.5 ppm of DMTS. The admixture may include at least 3 ppm, at least 5 ppm, or at least 7 ppm of DMTS. The diluted admixture includes no more than 3,000 ppm of DMTS. In some aspects, the admixture includes no more than 1,000 ppm, no more than 500 ppm, or no more than 300 ppm of DMTS. In some aspects, the admixture may include no more than 200 ppm, no more than 100 ppm, or no more than 50 ppm of DMTS. A single-phase admixture may include 1 ppm to 1000 ppm of DMTS. In some aspects, the admixture includes 3 ppm to 500 ppm of DMTS or 5 ppm to 100 ppm of DMTS. In some aspects, the admixture includes 10 ppm to 50 ppm of DMTS.

[0040] polar organic solvents

[0041] The compositions disclosed herein optionally include an organic solvent. In some embodiments, the organic solvent is a polar organic solvent. Polar organic solvents suitable for the concentrate compositions of this disclosure include ethanol, propanol, isopropanol, propylene glycol, ethylene glycol, glycerol, butyl cellosolve, butyl carbitol, diethylene glycol monoethyl ether, ethylene glycol monoethyl ether, and n-butanol. Other polar organic solvents may be used in the concentrate compositions. In some aspects, the polar organic solvent is an alcohol. In some aspects, the polar organic solvent is selected from ethanol, propylene glycol, and mixtures thereof. Polar organic solvents can provide stability to DMTS.

[0042] The concentrate composition according to this disclosure may include at least 50 wt% of a polar organic solvent. In some aspects, the composition includes at least 60 wt% or at least 75 wt% of a polar organic solvent. The concentrate composition may include at least 90 wt% of a polar organic solvent. In some embodiments, the concentrate composition includes at least 95 wt% or at least 98 wt% of a polar organic solvent. In some aspects, the concentrate composition includes 95 wt% to 99 wt% of a polar organic solvent. In some aspects, the concentrate composition does not contain a polar organic solvent.

[0043] The single-phase composition may include at least 1 wt% of a polar organic solvent. In some embodiments, the composition includes at least 5 wt% or at least 10 wt% of a polar organic solvent. The composition may include no more than 50 wt%, no more than 40 wt%, or no more than 30 wt% of a polar organic solvent. In some aspects, no more than 20 wt% or no more than 10 wt% of the composition is a polar organic solvent.

[0044] polar inorganic solvents

[0045] In some embodiments, the concentrate composition comprises 50 wt% or less of a polar inorganic solvent. Typically, the polar inorganic solvent is water. In some embodiments, the concentrate composition comprises 50 wt% or less, less than 30 wt%, less than 25 wt%, or less than 10 wt% of water. Improved stability of DMTS is achieved when the concentrate composition comprises less than 5 wt% or less than 1 wt% of water. Some concentrate compositions may be anhydrous. In other embodiments, the concentrate composition may comprise 50 wt% to 99 wt% of water. The concentrate composition may comprise only water as a diluent.

[0046] The composition can be formulated into a working composition. Alternatively, the concentrated composition can be diluted with a polar inorganic solvent to form a working composition. The polar inorganic solvent is typically water, but may include other suitable solvents. The working composition comprises at least 50 wt%, at least 60 wt%, or at least 70 wt% of a polar inorganic solvent. In some embodiments, the working composition comprises less than 90 wt% water.

[0047] amine

[0048] In some embodiments, the concentrate composition may include an amine. The amine may be selected from the group consisting of: trimethylamine (TMA), isopropylamine, triethanolamine, monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), methyldiethanolamine (MDEA), dihydroxyethylglycine (2-(bis(2-hydroxyethyl)amino)acetic acid), and histamine. Some amines can act as insect pheromones.

[0049] In some respects, amines are alkanolamines. Suitable alkanolamines include methyldiethanolamine (MDEA), monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), and mixtures thereof. In some respects, amines are MDEA.

[0050] In some embodiments, the concentrate composition of this disclosure optionally comprises at least 120 ppm of an amine. In some aspects, the concentrate composition comprises at least 240 ppm of an amine or at least 480 ppm of an amine. The concentrate composition comprises no more than 120,000 ppm of an amine. In some aspects, the concentrate composition comprises no more than 60,000 ppm or no more than 30,000 ppm of an amine. The concentrate composition comprises 120 ppm to 1,200 ppm of an amine.

[0051] The composition may optionally include at least 1.2 ppm of an amine. In some aspects, the composition includes at least 2.4 ppm, at least 3.6 ppm, at least 4.8 ppm, or at least 6 ppm of an amine. The composition according to this disclosure includes no more than 1,200 ppm of an amine. In some aspects, the composition includes no more than 900 ppm, no more than 600 ppm, or no more than 300 ppm of an amine. In some aspects, the composition includes 2 ppm to 200 ppm of an amine. The composition may contain 3 ppm to 100 ppm of an amine.

[0052] pH adjuster

[0053] The composition may optionally include a pH adjuster, which is typically an acid. Neutral to acidic pH values ​​have been found to reduce DMTS degradation, even in the presence of water without polar organic solvents. The acid may be an organic acid, such as acetic acid, malic acid, citric acid, lactic acid, formic acid, or glycolic acid, or an inorganic acid, such as phosphoric acid, sulfuric acid, nitric acid, or hydrochloric acid. In some embodiments, it is desirable to use phosphate, citrate, acetate, malate, lactate, or formate buffers to buffer the composition. If an alkaline source is required to adjust the pH to neutral, sodium hydroxide or potassium hydroxide, or carbonates or bicarbonates such as sodium carbonate or potassium carbonate, may be used, provided that the pH does not increase excessively. pH values ​​above 9 have been found to increase DMTS degradation. The concentrate composition according to this disclosure has a pH of at least 1. The concentrate composition has a pH of no more than 9. In some embodiments, the concentrate composition has a pH in the range of 1 to 9, 2 to 8, 2 to 7, 1 to 4, or 6 to 9.

[0054] Other ingredients

[0055] The concentrate composition may include other components. For example, other components may include carriers, surfactants, emulsifiers, desiccants, film-forming agents, and combinations thereof. In some embodiments, the concentrate composition includes pesticides or insecticides.

[0056] Exemplary Compositions

[0057] Table 1: Concentrate Compositions

[0058] Formula A (wt%) Formula B (wt%) Formula C (wt%) Formula D (wt%) DMTS 0.001-3 0.003-0.6 0.01-0.1 0.001-3 polar organic solvents 50-99.999 75-99.997 90-99.989 0 amine 0-12 0-2.4 0.001-0.4 0-12 acid 0-10 0-2.4 0.001-0.4 0-10 water 0-30 0-20 0.1-10 balance

[0059] Table 2: Compositions Used

[0060] Formula A (ppm) Formula B (ppm) Formula C (ppm) Formula D (ppm) DMTS 0.3-3,000 3-500 10-50 0.3-3,000 polar organic solvents 10,000-500,000 50,000-300,000 100,000-200,000 0 amine 0-12,000 0-600 1.2-200 0-12,000 acid 0-10,000 0-600 1.2-200 0-10,000 water balance balance balance balance

[0061] storage

[0062] Storage conditions can also affect the stability of DMTS in solution. DMTS solutions are stored in containers. Some container materials cause DMTS degradation. Some container materials accelerate DMTS degradation faster than others. Packaged concentrate compositions containing DMTS are preferably contained in containers that are substantially free of materials that cause DMTS degradation. In some embodiments, the container is a dispenser. The container can be a metal container or a glass container. Preferably, the container is not a plastic container.

[0063] In some embodiments, the container is a fluorinated HDPE container. The container may be fluorinated to level 3. The container may be fluorinated to level 5. Preferably, the container is not a non-fluorinated HDPE container.

[0064] The packaged concentrate composition is phase stable. In some embodiments, the single-phase concentrate composition according to this disclosure is phase stable in a container.

[0065] DMTS in the concentrate composition degrades by no more than 40% within one year under normal storage conditions at ambient temperature. When stored at 54°C, DMTS in the concentrate degrades by no more than 30% within two weeks. In some embodiments, DMTS in the concentrate composition degrades by no more than 20% within one year when stored at room temperature.

[0066] The DMTS in the composition degrades by no more than 60% within one year at ambient temperature. In some aspects, the DMTS in the composition degrades by no more than 50%.

[0067] method

[0068] Methods for inhibiting the degradation of dimethyl trisulfide (DMTS) involve the preparation of a concentrated composition. As described above, DMTS is combined with a polar inorganic or organic solvent to form a concentrated composition. The DMTS in the solution is stored stably in a container for one year at ambient temperature (approximately 15-25°C). The container is preferably made of the aforementioned material that will not cause degradation of DMTS.

[0069] A method for preparing an insect pheromone solution is also described. Any of the above-described concentrated compositions is diluted with a polar inorganic solvent (e.g., water). In some embodiments, at least 120 ppm of an amine is added to the working solution. In some aspects, the amine is MDEA. An insecticide can be added to the concentrated or working solution to kill insects attracted by the pheromone.

[0070] When stored at 54°C, the concentrated composition according to this disclosure is stable for up to 2 weeks. This simulates storage of the composition at room temperature for up to one year. In some embodiments, the concentrated composition is stable for more than one year when stored at room temperature or ambient temperature (about 20°-25°C). For best results, the concentrated composition should be diluted with water immediately before use.

[0071] Example

[0072] Accelerate stability storage condition settings

[0073] The EPA's accelerated stability guidelines recommend storing the composition at 54°C for two weeks. This is considered equivalent to storing the composition at room temperature for one year. These conditions were applied to the following studies to ensure that DMTS could be formulated according to the EPA guidelines.

[0074] Example 1

[0075] Previous observations have shown that DMTS decomposes when stored in an aqueous solution, regardless of the type of container in which it is stored. Specifically, DMTS combined with MDEA exhibits accelerated decomposition in water. It is hypothesized that the presence of MDEA accelerates the decomposition of DMTS. Comparisons are made between DMTS alone and DMTS containing MDEA.

[0076] Figure 1 A comparison of DMTS recovery over time is shown. 120 ppm DMTS alone is compared to 120 ppm DMTS containing 420 ppm MDEA. Even under the accelerated conditions described above, DMTS degradation in water was still observed over time. However, the degradation was significantly slower compared to formulations mixed with MDEA. It was determined that separating DMTS into its own solution significantly improved stability.

[0077] Example 2

[0078] Various conditions were modified to improve the overall stability of DMTS in solution. First, the pH was lowered by buffering the solution. It was predicted that a lower pH might inhibit the catalytic decomposition of DMTS. The solution was buffered to pH 6 and compared with a control. 32 ppm DMTS was stored in a glass container at 40°C for 7 days, followed by a further 15 days at 54°C.

[0079] The results are shown in Figure 2 The samples using an N2 capping layer and soft water provided the most unstable conditions for DMTS. Samples in ethanol-containing solutions showed minimal degradation of DMTS. Samples containing a pH 6 buffer exhibited faster decomposition than the control. Buffer ions promoted further decomposition of DMTS rather than improving stability.

[0080] Example 3

[0081] In this example, DMDS is added to DMTS. It is assumed that if the pathway for DMTS to decompose into DMDS is in equilibrium, then the additional DMDS will stabilize the decomposition pathway. DMDS is added to formulations containing only DMTS and DMTS containing MDEA.

[0082] The results are shown in Figure 3 The addition of DMDS does not slow down the decomposition of DMTS. This indicates that the decomposition pathway of DMTS is irreversible.

[0083] Example 4

[0084] The results in Example 2 indicate that ethanol can slow the degradation of DMTS. It is hypothesized that propylene glycol (PG) may have a similar effect. Samples were prepared in water with 8 ppm and 4 ppm DMTS as controls. Experimental samples included 8 ppm DMTS containing either 1% or 10% PG. Samples were also prepared in unfluorinated HDPE containers.

[0085] The results are shown in Figure 4 In the middle section, some improvement was observed using PG, with greater benefits seen at higher concentrations of PG. Samples in HDPE containers showed significantly faster degradation of DMTS at 54°C. This indicates that non-fluorinated HDPE containers do not help slow down the degradation of DMTS in solution.

[0086] Example 5

[0087] This example investigated the effect of HDPE container fluorination on the stability of DMTS. The stability of DMTS was recorded during 14 days of storage at 54°C. Glass containers were used as controls. HDPE containers with no fluorination (F0), grade 3 fluorination (F3), and grade 5 fluorination (F5) were tested. DMTS samples were prepared as an 8 ppm DMTS dilution in water containing 10% PG.

[0088] The results are shown in Figure 5 In the middle, non-fluorinated HDPE containers showed the fastest rate of DMTS degradation. Samples stored in grade 5 fluorinated HDPE showed best results similar to those in glass containers.

[0089] Example 6

[0090] Considering the improvements seen using 10% PG as a solvent, higher concentrations of PG were tested. The stability of 0.28% DMTS in 100% PG at 54°C for two weeks was tested. Storage in glass containers was compared to that in Grade 3 fluorinated HDPE containers.

[0091] The results are shown in Figure 6Similar stability results were observed for each type of container. The 14-day recovery percentage remained above 90%, showing a significant improvement compared to previous experiments using 10% PG.

[0092] Example 7

[0093] Other solvents, undiluted with water, were tested. A sample of 0.03% DMTS was prepared in 100% solvent. The solvents tested were ethanol in a glass container, PG in a glass container, PG in a non-fluorinated HDPE container, and glycerol in a glass container.

[0094] The results are shown in Figure 7 In the case of DMTS recovery, over 90% recovery was observed in glass containers using 100% ethanol or propylene glycol. In the case of DMTS recovery, at least 50% recovery was achieved in glass containers using glycerol.

[0095] Overall, increasing the concentration of solvents other than water can significantly improve the stability of DMTS in solution. Studies have shown that higher solvent content allows for the use of higher concentrations of DMTS in formulations without concern for stability. Furthermore, research on container materials indicates that Grade 3 or Grade 5 fluorinated HDPE bottles perform similarly to glass containers in maintaining DMTS stability.

[0096] Example 8

[0097] In this example, 0.03 wt% (300 ppm) of DMTS was dissolved in a solvent consisting of 100% ethanol (EtOH) or 100% propylene glycol (PG). This study is very similar to Example 7. DMTS recovery was recorded over a 14-day period. The DMTS solution was stored under accelerated conditions at 54 °C. The results are shown in... Figure 8 In the 14-day period, less than 10% of DMTS degraded for both EtOH and PG. DMTS dissolved in EtOH showed slightly better stability.

[0098] Example 9

[0099] In this example, a lower concentration of DMTS was used to produce the composition. 32 ppm of DMTS was dissolved in a 100% aqueous solution or a combination of 10% PG and 90% water. The same accelerating conditions were used for 14 days. Results are shown in... Figure 9 In this study, water was used as the sole solvent to recover over 70% of the DMTS. However, using a 10% PG aqueous solution improved the stability of the DMTS and provided over 80% recovery. This study indicates that dilution of the concentrate composition does negatively impact the stability of DMTS, but the composition still maintains relatively high stability.

[0100] Example 10

[0101] Even lower concentrations of DMTS were tested to determine whether further dilution of the concentrate affected DMTS stability. Solutions containing 8 ppm of DMTS were prepared. DMTS was dissolved in water, an aqueous solution of 1 wt% PG, and an aqueous solution of 10 wt% PG. DMTS recovery was greater than 60% for all samples. Solutions containing PG showed higher levels of stability, with the 10% PG solution providing over 80 wt% recovery. Reduction in the amount of DMTS had a slight negative impact on stability.

[0102] Finally, solutions containing 1 ppm DMTS were tested to determine whether the composition containing a small amount of DMTS could remain stable during a two-week test period at 54°C. Figure 11 The results of diluting 1 ppm DMTS in water, ethanol, or both are shown. Hard water has the greatest negative impact on DMTS stability. By day 14, no DMTS remained in the solution. Deionized (DI) water resulted in less than 40% DMTS recovery. Adding ethanol to the water produced a more stable DMTS solution, but even in 100% EtOH, only 60% recovery of the DMTS solution was likely achieved after 14 days. This indicates that DMTS is less stable in more dilute solutions.

[0103] When the solution contains PG Figure 12 Similar results were observed. Adding PG to the water improved the stability of DMTS, but even at 100% PG, recovery was less than 60%.

[0104] Example 11

[0105] In this example, DMTS at various concentrations in water, ethanol (EtOH), and propylene glycol (PG) were prepared with and without MDEA, and their degradation was tested. The pH was adjusted to 2, 7, or 12 ± 0.5 using sodium hydroxide or hydrochloric acid. DMTS concentrations were measured by gas chromatography on day 0 and day 14, and the percentage of degradation was calculated based on these values. The formulation was capped and stored at 54°C for two weeks. The results are shown in Table 3 below.

[0106] Table 3: DMTS degradation at 54℃ for 14 days

[0107] formula DMTS concentration diluent Existing MDEA pH degradation% 1 50ppm water 0ppm 7 13 2 50ppm 5% PG 0ppm 7 16 3 50ppm 50% PG 0ppm 7 4 4 50ppm 95% PG 0ppm 7 1 5 50ppm water 0ppm 12 53 6 50ppm water 200ppm 2 20 7 50ppm water 200ppm 12 100 8 50ppm 50% PG 200ppm 7 90 9 50ppm 95% PG 200ppm 7 1 10 50ppm 50% PG 200ppm 2 67 11 50ppm 95% PG 200ppm 2 4 12 50ppm 50% PG 200ppm 12 100 13 50ppm 95% PG 200ppm 12 100 14 2800ppm 100% PG 0ppm 7 6 15 2800ppm 100% PG 11000ppm 7 31 16 300ppm 100% EtOH 0ppm 7 3 17 300ppm 100% PG 0ppm 7 8 18 250ppm 100% PG 0ppm 7 1 19 8ppm water 0ppm 7 26 20 8ppm water 32ppm 7 97 21 8ppm water 0ppm 7 38 22 8ppm 1%PG 0ppm 7 23 23 8ppm 10% PG 0ppm 7 20 24 32ppm 10% PG 0ppm 7 15 25 32ppm water 0ppm 7 27 26 32ppm water 0ppm 7 26 27 32ppm 5% EtOH 0ppm 7 24 28 32ppm 50% EtOH 0ppm 7 6 29 32ppm water 128ppm 7 98 30 10ppm water 40ppm 7 97 31 3ppm water 12ppm 7 100 32 3ppm water 0ppm 7 4

[0108] Table 3 shows that when water is chosen as the diluent and MDEA is absent, at a neutral pH (pH = 7; see formulations 1, 19, 21, and 32), 40% or more of DMTS remain after two weeks of testing at 54°C. When MDEA is added to water and DMTS at a neutral pH, almost all of the DMTS degrades after two weeks at 54°C (e.g., formulation 20), but when the pH drops to 2, only 20% of the DMTS degrades after two weeks of storage at 54°C. This indicates that water can serve as a suitable carrier for DMTS at neutral and acidic pH levels, and as a suitable carrier for DMTS+MDEA at acidic pH levels. Furthermore, such formulations do not exhibit significant DMTS degradation after two weeks at 54°C, and the formulations are stable as a single-component composition.

[0109] Table 3 also shows that at neutral pH (pH=7), a 50 / 50 mixture of water and propylene glycol can further reduce the amount of DMTS degraded. Compare formulations 1 and 3. When the diluent is 95% propylene glycol, the amount of DMTS degraded is reduced even more. (See formulation 4.) When MDEA is added to DMTS, a 50 / 50 mixture of propylene glycol and water is insufficient to prevent DMTS degradation at neutral pH. See formulation 8, which shows that 90% of the DMTS degrades after two weeks at 54°C. However, increasing the propylene glycol concentration to 95% (formulation 9), decreasing the pH from 7 to 2 (formulation 10), or both (formulation 12) at neutral pH all reduce the amount of DMTS degraded.

[0110] Table 3 also shows that ethanol is a good diluent for maintaining DMTS concentration. After two weeks at neutral pH and 54°C, a 50 / 50 combination of ethanol and water resulted in only 6% degradation of DMTS (Formula 28 vs. Formulas 25-27). Even when the concentration of DMTS was increased from 32 ppm to 300 ppm, at neutral pH, increasing the ethanol concentration to 100% of the diluent reduced the degradation to only 3% (Formula 16).

[0111] While some embodiments have been described, other embodiments may exist. Although this specification includes specific details, the scope of this disclosure is indicated by the appended claims. The specific features and behaviors described above are illustrative aspects and embodiments. After reading the description herein, various other aspects, modifications to embodiments, and equivalents thereof will become apparent to those skilled in the art without departing from the spirit of this disclosure or the scope of the claimed subject matter.

Claims

1. A single-phase composition comprising: Dimethyl trisulfide (DMTS) ranging from 30 ppm to 6,000 ppm; and An amine ranging from 120 ppm to 11,000 ppm, wherein the amine is methyldiethanolamine; At least 90 wt% of a polar organic solvent, said polar organic solvent being selected from ethanol, propylene glycol, and mixtures thereof; and pH range of 1 to 7 The DMTS thereon degrades by no more than 40% within one year of storage, and the composition is phase stable in the container.

2. The single-phase composition according to claim 1, wherein the composition contains 30 ppm to 5000 ppm of DMTS.

3. The single-phase composition according to claim 1, wherein the DMTS degrades by no more than 30% within one year of storage.

4. The single-phase composition according to claim 1, wherein the composition comprises at least 95 wt% of a polar organic solvent.

5. The single-phase composition according to any one of claims 1 to 4, wherein the composition contains less than 10 wt% water.

6. The single-phase composition according to any one of claims 1 to 4, wherein the composition contains less than 1 wt% water.

7. The single-phase composition according to any one of claims 1 to 4, wherein the composition comprises 120 ppm to 1,200 ppm of an amine.

8. The single-phase composition according to any one of claims 1 to 4, wherein the composition has a pH of 1 to 4.

9. A packaged composition comprising: Dimethyl trisulfide (DMTS) from 30 ppm to 6,000 ppm; An amine in the range of 120 ppm to 1,200 ppm, wherein the amine is methyldiethanolamine; At least 90 wt% of a polar organic solvent, wherein the polar organic solvent is selected from ethanol, propylene glycol and mixtures thereof; pH values ​​from 1 to 7; and A container for containing the composition, the container being selected from the group consisting of: metal, glass, or fluorinated HDPE. The DMTS thereon degrades by no more than 30% when stored at 54°C for at least 2 weeks, and the composition is phase stable.

10. A single-phase composition comprising: Dimethyl trisulfide (DMTS) from 30 ppm to 3000 ppm; An amine in the range of 120 ppm to 1200 ppm, wherein the amine is methyldiethanolamine; At least 95 wt% of a polar organic solvent, said polar organic solvent being selected from ethanol, propylene glycol, and mixtures thereof; and pH range of 1 to 4; The DMTS mentioned herein degrades by no more than 40% within one year.

11. The single-phase composition of claim 10, wherein the composition comprises 50 ppm to 2800 ppm of DMTS.

12. Use of the composition according to any one of claims 1-11 as an insect attractant.

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