# Which lab equipment should we use to mix a thick solution?

1. Dec 1, 2014

### Thondyl

Hi all!

We're trying to dissolve a mixture of organic matter with a solvent that is highly volatile. Currently, we have to shake the solution very frequently to ensure the organic matter doesn't settle down on the bottom of the flask.

However, it takes a REALLY long time for the organic matter to completely dissolve and we think we could greatly speed up the process if we can use an equipment that automates the shaking.

The following is a list of equipment that we have tried/thought about but all of them had some problems:

Magnetic stirrer - The organic matter is too thick for the rods to spin properly. The rod quickly moves out of position and spins out of control.

Overhead stirrer - The container must be closed -- the solvent evaporates too quickly and the reaction takes several days to complete.

Orbital shaker - The best option so far but still not very effective. The organic matter is heavy so it settles down on the bottom and isn't really affected by the shaker.

Blender - We haven't tried this but we are afraid the blender might fail since it isn't designed to operate 24 hours for several days at a time. Also, the speed is too great and its also really noisy to leave in the lab.

Any ideas/recommendations on which equipment we should use will be greatly appreciated!

2. Dec 1, 2014

### Bystander

Soxhlet extraction?

3. Dec 1, 2014

### Thondyl

Sorry but could you clarify what you meant? I don' think that's what we're trying to achieve.

We just need an equipment that will mix the solution for an extended period of time.

4. Dec 1, 2014

5. Dec 1, 2014

### Bystander

You're wanting solvent in contact with undissolved material for days without the noise of a shaker (paint cans), or risking mechanical failures; Soxhlet extraction will put hot solvent over undissolved material, leave filtered solution in the boiler, and given an efficient condenser, can be left for days.

6. Dec 1, 2014

### Thondyl

We thought of that but it is too small. The solution is in a 1L erlenmeyer flask and it would be really tedious to pour the solution into each test tube.

The solution extremely sensitive to heat so I don't think that'll work.

Last edited: Dec 1, 2014
7. Dec 1, 2014

### Bystander

Heat sensitive slow dissolving gunk ... Have you tried the short bars with the magnetic stirrer?

8. Dec 1, 2014

### Thondyl

We did. The bar had a hard time spinning and couldn't stay on the center for very long. The volume is also too great for it to effectively stir even if it did work perfectly.

9. Dec 1, 2014

### Ygggdrasil

If orbital shaking seemed most effective, you may want to consider using a baffled flask. These have indentations on the bottom that help to distrub the fluid shaking around in the bottom of the flask. Biologists use these flasks to better aerate microbial cultures, but in your case, it may help mix your solution better than shaking in a standard flask.

10. Dec 1, 2014

### Thondyl

Thank you! We'll look into it.

11. Dec 2, 2014

### Thondyl

After searching for a while, we found that a bottle roller machine would be perfect for our project: http://static.coleparmer.com/large_images/3620202.jpg

However, when we contacted the manufacturer they told it is going to cost us around $2000!!!! Why does it cost so much??$2000 is way too much for an equipment that simply just rotates the bottle around.

Does anyone know where we could purchase this (or a similar) machine for a lower price? Its fine if we have to DIY or do some simple modifications.

12. Dec 2, 2014

### Bystander

Cole-Parmer is the Ford/Chevrolet of laboratory equipment manufacturers/dealers and cheap as you're going to find from that sector. You might try looking in Edmund for lapidary equipment that rolls small jars for rock polishing.

13. Dec 2, 2014

### Thondyl

Thanks!! We found a couple of bottle rollers at Cole-Parmer's website but they start at \$1100 which is still a little too expensive for us. However, the rock tumbler is PERFECT for our needs and the price is affordable too.

14. Dec 3, 2014

### Staff: Mentor

You will find a lot of DIY projects on the web with rock tumblers that cost just a few bucks ;)