SEED OIL

24 December, Christmas Eve! Merry Christmas! Feliz Navidad! Buon Natale! Lab is open for half day only and we need to do stuff pronto. 

From the soxhlet extraction, we managed to retrieve the seed oil from the round bottom flask. However, it is contained with a lot of impurities. Hence, we need to purify to obtain a pure oil sample. 

We performed suction filtration with a vacuum pump to remove any impurities in the extracted rambutan oil. By using Vacuum filtration, it speeds up the process of filtration, as compared to the conventional filtration method.

After filtration, the oil was free from impurities.

We then proceeded with simple distillation, with the temperature set around 80°C to remove the ethanol in the oil. The boiling point of the ethanol is around 78°C. At 80°C, all the ethanol content in the oil will vapourised and condense as distillate.

The distillate (ethanol) was removed and disposed.

After distillation, the extracted rambutan oil were seen to have a darker colour.

The oil was left to cooled and then stored in a small glass bottle. After letting the oil to cool, there seemed to be 2 layers in the oil.

Next episode on RAMBUTAN EXTRACTION SERIES, Transesterification! In the next episode, the J-team faces another challenge, how to convert the seed oil into biodiesel? Transesterification? WHATS THAT?? Can they obtain the necessary equipment and ingredients to perform this daunting task? STAY TUNED ON CHANNEL J!

SOXHLET YOOOO

We went to W315 (we forgot to book but lucky us there's empty slot yay) and then we performed soxhlet extraction using the soxhlet apparatus provided. 200ml of ethanol was used to extract the oil from the rambutan seeds. 

We used soxhlet extraction because it is a more efficient method as compared to the use of mechanical press.

 As soxhlet extraction uses the theory of washing the sample over and over again with the use of the solvent, it has the ability to obtain more bio-oil. Furthermore, soxhlet is able to isolate desired oil, which has limited solubility in the solvent and the impurity is insoluble in a solvent. Thus making the bio-oil have higher purity. 

We used soxhlet extraction because it is a more efficient method as compared to the use of mechanical press.

As for the use of ethanol, it was decided upon when the use of n-hexane was deemed too dangerous to be used as the flash point was way too low, which may cause imminent danger to the user. Ethanol is a safer solvent to use compared to n-hexane. We don't wanna die yet, we're too young.

The experimental setup is shown below.

Ethanol was heated so that it can be vaporised, it is being heated through water bath as the round flask heater was faulty (take note).

This gif illustrates the intended process of soxhlet extraction. Ethanol vaporises, then condenses on the seed stack. Condensed ethanol is collected, and when the return tube is full, the seed stack is submerged, the reservoir will fall back to the flask.

We did soxhlet extraction for about 2 hours then we noticed that there wasn’t any significant differences. Progress was very minimal. The ethanol was supposed to vaporise and then condense back, and cause the seed stack to become wet. We noticed ethanol condensing but it was only a few droplets even after two hours. Wow we could've used the two hours to do so much other things but alas

We suspected that the cotton layer was too thick (sometimes you shouldnt 'play safe' too much by adding too much), hence we removed a huge portion of it.

Due to the thick cotton layer, all the condensing ethanol is soaked in by the cotton, thus, only little ethanol is able to come into contact with the Rambutan seeds.

Hence, when the cotton layer is reduced, ethanol is able to pass through easily and perform leaching. The time of the process is also significantly reduced.

After which, ethanol was able to condense at a fast rate. Finally we weren't waiting so much for nothing!

We took around 6 hours to complete soxhlet extraction. In the meanwhile, we spent hours doing things and talked about almost anything. Other than that we were on our phones on social medias, we keep refreshing our timelines in the hope of seeing new posts, we bugged other busy people on Whatsapp, trying to talk to them, we walked around campus on an expedition (we took turns in shifts) just to pass time and we watched horror movies (yes in bright daylight). We monitored the process in the meanwhile of course.

We managed to do six cycles of soxhlet extraction. A total of 8 hours were spent.

A cycle is completed when the return tube is completely full, the seed stack is completely submerged with condensed ethanol, and then the return tube will empty itself along with the seed stack. The liquid reservoir on the seed stack will flow down to the round-bottom flask that contained ethanol.

During the sixth cycle, the solvent at the sight glass started to become quite clear, hence, we decided to stop the experiment. Finally we're done for the day. But nope, tomorrow still need go lab. At least soxhlet extraction is done!

CRUSHING SEEDS

            

After eating (and making rambutan syrup with F&N rose syrup -I recommend this- ) 46 rambutans, this is what we got; 46 seeds. Doesn't seem that much from here but trust us we took long to finish it.

All the flesh on the rambutans were removed till the seed is left, bare naked.

Initially, we tried to use a mortar and pestle to grind the rambutan seeds into finer pieces. However, we realised it takes too long. Of course it does. Naeem's mom scolded us and said 'Do you want to do this till night?!'

In the end, we employed the help of a wet blender and managed to use it to shred the rambutan seeds into finer pieces. It was noisy, shredding the seeds between the blades. This blender is supposedly used for food with very wet mediums.

1.4. The seeds were spread out evenly on the tray.

Then, the seeds were dried in an oven to remove moisture in the seeds at 1100C for 20 minutes.  

After drying, the total mass of seeds weigh 101.37g. The seeds smell nice. Baked seeds. Remember how even the rambutan seeds is beneficial? We should eat them. Wait, no we need to make biodiesel.

INTRO

HEY!!!!11!!!!1!!! Firstly, let us introduce ourselves; we are THE AWESOME J TEAM

- CONSISTING OF NAEEM, XING HUI, HONG WEI AND J FROM DCHE 2B/05 (we r very fun and cool peeeople to be with k)!!!

Our group will be using this blog to keep updates on our Green Engineering YES Assignment. For our YES assignment, we decided on using rambutan seeds, cause seeing how we're living in the Southeast Asia, a common fruit in this region would be unique and also easy to get. We will be converting rambutan seeds into oil first through soxhlet extraction, then we will convert into our final product, biodiesel through transesterification.

(mmm, just looking at that makes you want to savour them) 
Rambutan is also favourable in making oils, as it has 39% oil percentage in its seeds, higher than its 'rivals', other native to southeast asia fruits like lychee and longan. 
Rambutan is always coined with the term 'exotic superfruit', it has a lot of benefits when eaten (strong antioxidant, increase immunity, cure common illnesses, boosts energy, lower sugar levels etc etc etc)

Even if it is not consumed, it still brings a lot of benefits to the table! (bark can get rid of thrush, roots as repellent to remove internal worms in fruits, leaves to cure headache, fruit skin layer made into decoction can remedy dysentry)

Our plan is firstly to use soxhlet extraction to extract oil from the rambutan seeds.

We chose soxhlet extraction because it is a more efficient method as compared to the use of mechanical press.

As soxhlet extraction uses the theory of washing the sample over and over again with the use of the solvent, it has the ability to obtain more bio-oil. Furthermore, soxhlet is able to isolate desired oil, which has limited solubility in the solvent and the impurity is insoluble in a solvent. Thus making the bio-oil have higher purity.

In order for efficient soxhlet extraction, the seeds are to be grinded into small pieces and also dried to remove moisture content.

After extracting oil, we would proceed with transesterification to produce our desired biodiesel, in which glycerin will also be produced. 

We'll see you later for more updates and we'll explain further!