Organic compounds of course deteriorate upon storage. Depending on the sensitivity for temperature, oxygen, moisture, self-reactivity, stability of bonds, one needs to re-test chemicals from time to time (at least, if you plan to sell them and claim them to have a certain purity).

If your compound does not crystallize, it's not a real problem, IMHO, as long as you can demonstrate the identity (e.g. by IR and HPLC or GC) and purity (HPLC or GC) and quantify residual solvents (or assumed impurities won't harm subsequent reactions and the amounts used are not critical).

However, keep the total cost in mind, it might save time and money to buy fresh material, dimedone is not that expensive.

there is no doubt that quality and structure of chemical materials would be changed over time, however the storage condition is a matter of high importance to consider. Nevertheless, there are different states of fragility for distinct types of materials. First of all take the appearance into account for any unusual change in color or viscosity, then try to take NMR test so as to assure. Comparing the result with previously submitted ones from library will guarantee reliability.

Overall, never start a synthesis procedure unless you are completely confident about the quality of materials, otherwise you will confront with whole different outcome.

It is better NOT to use it. Organic compounds can degrade over time, leading to changes in their chemical properties and potential loss of effectiveness. Here are some pros and cons of using expired organic compounds:

Pros of using expired compounds:

1. Cost-saving: Expired compounds may be available at a lower cost or even free of charge, making them attractive for researchers or industries operating on a tight budget.

2. Limited applications: In some cases, expired compounds may still be suitable for certain applications where their degraded properties do not significantly impact the desired outcome. For example, if the compound is being used as a reference standard or for non-critical preliminary experiments.

3. Educational purposes: Expired compounds can be useful in educational settings for teaching purposes, demonstrations, or as practice materials for students to familiarize themselves with laboratory techniques.

Cons of using expired compounds:

1. Decreased potency or activity: Over time, organic compounds can undergo chemical reactions that lead to degradation, resulting in reduced potency or activity. This can affect their performance in experiments or applications, making them less reliable or ineffective.

2. Inaccurate or inconsistent results: Using expired compounds can introduce variability and uncertainty in experimental results. This can be problematic, especially in research or industrial settings where accuracy and reproducibility are crucial.

3. Safety concerns: Expired organic compounds may pose safety risks. Their degradation products or impurities could be toxic, unstable, or reactive, potentially leading to hazardous situations during handling or when used in reactions or processes.

4. Unreliable data: When using expired compounds in research or industrial processes, the obtained data may not be reliable or representative of the compound's true behavior. This can hinder scientific progress, lead to erroneous conclusions, or impact product quality in industrial applications.

5. Regulatory compliance: In regulated industries, the use of expired compounds may not comply with quality control standards or regulatory requirements. Using expired compounds could result in non-compliance, potentially leading to legal or regulatory consequences.

Hope it helps:credit AI

The product is relatively stable . It depends on the condition used for its storage . If the product is not too expensive do not loose your time, start with new material.

Check the melting point (after drying in an exsicator) mp must be 147-150 °C. If the amount is substantial then a recrystallization from chloroform or acetone could be considered.

Otherwise it would be recommended to use fresh material from a supplier

Actually the stability (or expiry time indirectly) depends on the nature of compounds, condition of preservation i.e atmosphere, temperature, moisture or humidity, presence of air, light etc. Some compounds are very stable and can be used even after 40-50 years! I have used ethylene oxide (0preserved in sealed ampule) made in British period of India! It was quite good. While many compounds are quite unstable and can't be preserved at all even when kept under inert atmosphere even at lower temperature. The compounds containing hetero atoms specially nitrogen undergo aireal oxidation and turns brown. Some of such impure compounds can be purified by recrystallization, column chromatography or distillation under at normal or reduced pressure but some times the decomposition is to such extent that the compounds are not suitable for use at all. In general all organic compounds need to be preserved in absence of light, moisture, air and low temperature and in sealed condition for longer life time and less decomposition. Use of inert atmosphere gives better results often.

Organic small molecules usually have an expiration date because some of them are prone to oxidation, thermal decomposition, and polymerization. They can only be stored for a short period of time in a dark, cool, and dry environment, depending on whether the packaging and storage conditions comply with regulations.

It is possible that the age of the dimedone could have affected the physical state of your newly synthesized compounds, but it's difficult to say for certain without more information. Here's why:

Possible reasons for the age being a factor:

Degradation: Over time, chemicals can degrade into other compounds, losing their original properties. If the dimedone had degraded significantly, it could have affected the chemical reactions involved in your synthesis, leading to different products or impurities that remain liquid. Moisture absorption: If the dimedone was not stored properly, it might have absorbed moisture from the air over time. Moisture can act as a reactant in some chemical reactions and alter the outcome. Loss of reactivity: Certain chemicals lose their reactivity over time, making them less efficient in participating in reactions. This could lead to incomplete reactions and the formation of liquid byproducts.

However, there are also other factors that could be responsible for your issue:

Impurities: The presence of the two other unidentified materials in the initial dimedone could have interfered with the reactions and influenced the product characteristics. Synthesis errors: Mistakes in the synthetic procedure, such as incorrect proportions, temperature, or timing, could have led to unwanted products with different physical properties. Incomplete crystallization: If the newly synthesized compounds are supposed to solidify but haven't yet, it could be due to factors like insufficient concentration, rapid cooling, or the presence of impurities that inhibit crystal formation.

Recommendations:

Analyze the dimedone: Check the purity of the dimedone using analytical techniques like chromatography or spectroscopy. This will help you determine if degradation or impurities played a role. Review your synthesis steps: Carefully re-evaluate your synthetic procedure to ensure all steps were followed correctly and the conditions were optimal. Compare with literature: Look for similar syntheses in the scientific literature and compare their procedures and results with yours. This might identify potential issues or variations you need to consider. Seek expert advice: If you're still unsure about the cause, consult a chemist or synthetic organic expert for professional guidance. They can analyze your specific situation and suggest solutions for troubleshooting and successful future attempts.

Remember, while the age of the dimedone is a possibility, it's crucial to systematically consider all other factors and perform proper analysis to accurately diagnose the problem and improve your synthesis outcomes.