Yiwei+Wang+log

For the final paper, I think I would probably do something about stevia and its comparison with other non-calorie sweeteners.

Assignment 3 Describe 10 strategies for obtaining boiling points 1.CRC handbook of Chemistry and Physics [] Log on to the CRC handbook website, there is a “text search” on the upper right position of the website. Enter “the compound name bp” There will be an interactive table under the physical constant of organic compounds or inorganic compounds based on the compound you’re choosing. For instance, tetrahydrofuran:

2.Reaxys [|https://www.reaxys.com] Log on to the Reaxys website, and draw the structure of your compound under “Substances and Properties” bar and click search button. Then boiling point could be found in physical data—boiling point with several reference papers indicating several boiling point value.

3.Wikipedia [|http://en.wikipedia.org] Search t “your compound name” on Wikipedia website and get to the compound Wikipedia page, boiling points could be found on the right under the properties.

4.Wolframalpha [|http://www.wolframalpha.com] Directly search your compound name on the website and boiling point is under the “basic properties”

5.Sigma-Aldrich [] Search the compound name or CAS number on the Sigma-Aldrich website and then select the product of your choice like anhydrous or not. Then on the compound page, there will be a properties sheet on the left of the page and boiling point could be found in the “bp” row.

6.NIST [] Log on to the website and search with compound name or CAS number, and in your compound’s page, boiling point could be found in the “phase change data” showed in Tboil.

7.Google https://www.google.com/ Google could give us some compounds’ boiling point with different sources. Just input “ boiling point of (your compound CAS number)”

8.Chemspider [] Search your compound name in the chemspider search bar and it will show boiling points with different sources and predicted boiling point is also showed in the same page.

9.MSDS [] Go to the Oxford MSDS website and click the “CAS number”, than click the “A list of CAS numbers for selected chemicals” and select your compound’s CAS number’s initial figure. Find your compound in the next page and click on that, then this compound’s MSDS data is showed on the screen.

10.Chemical Validation data [] People on cheminfo class for the last a few years have done an incredible job on the chemical properties validation including boiling point.So we might be able to found the boiling point of your compound by this chemical validation explorer. Go to that website and scroll down the tab and try to found the boiling point.

Assignment 2 Article: Geuns JM (2003). "Stevioside". // [|Phytochemistry] // **64** (5): 913–21. [|doi:10.1016/S0031-9422(03)00426-6] **[Full Marks JCB]**

Summary: 1.Introduction 1.1Stevia rebaudiana Bertoni is originated from South America and is in the Asteraceae family. 1.2The structures of the sweet components in Stevia leaves are shown in Figure.1. Stevioside is the major component which tastes 300 times sweeter than sucrose. 1.3Some controversies in the usage of Stevia plant and its extracts in different countries. And the advantages of using stevioside as a dietary supplement.

2. Biosynthesis of stevioside 2.1People found that the stevioside biosynthesis is by undergoing a 2-C-Methyl-D-erythritol-4-phosphate(MEP) pathway and demonstrated it is different with the gibberellins biosynthesis. 2.2People concluded that the changes in the regulation of certain enzymes contributed to the large fraction of stevioside accumulation in the Stevia plant and made it possible for preventing the overlap between steviol and gibberellins biosynthesis. 2.3Many scientists had successfully described the changes in regulation of the enzymes.

3.Acute and chronic toxicity 3.1 It’s reported that an acceptable daily intake is 7.9mg stevioside/kg BW(body weight).And the author think it’s just a minimum value. 3.2Past reports didn’t use procedures which is quite similar to the use of stevioside in food.And the acute oral toxicity is very low. 3.3From the past reports, hamsters are more sensitive to steviol than other experimented animals. 3.4Past chronic toxicity reports with rats and hamsters could deduce 25mg/kg BW of acceptable daily intake.

4Steviol, the controversial metabolite of stevioside 4.1Scientists found mutagenic effects of steviol,the metabolite of stevioside,but the activity is pretty low and it’s safe fro daily use as sweetener. Also, as the hamsters are more sensitive to steviol, the experiments carried on the hamsters should be questioned.

5.Uptake and metabolism of stevioside 5.1Scientists found that oral stevioside can’t be taken up by the human body and no digestive enzymes of the animals or men’s intestines could metabolize stevioside into steviol. 5.2Various reports showed that bacteria from the caecum or colon could metabolize stevioside into steviol and indicated that in vivo steviol was the only mebolite of stevioside. 5.3Past works of the scientists showed that steviol could be easily uptaken by the intestines but possibly not the colon. 5.4The author performed the experiments to concluded that steviol could barely be taken up by the colon because it was absorbed by some compounds in there.

6.Stevioside and carcinogenicity 6.1Evidences showed that stevioside had nothing to do with the carcinogenicity. 7.Fertility and teratogenicity 7.1Multiple experiments and reports on rats has proved that stevioside has nothing to do with the fertility issues. 7.2Also stevioside has no effect on spermatogenesis,interstitial proliferation and tumor formation. 7.3Author rationalize that the previous work by Melis was not convincible because the condition he used was too extreme and it was still not clear whether the effect was due to the stevioside component. 7.4Experiments carried on chicken embryos proves that stevioside and steviol has no effect even on prenatal animals. 7.5Various papers proved that normal use of stevioside as sweetener has no effect on fertility and teratogenicity.

8.Bio-availability of nutrients from the diet 8.1Experiments carried on modern broiler chickens and laying hens all indicated that stevioside has no effect on bio-availability of nutrients. 8.2Also, no different in weight gain for animals feeding with sugar or stevioside.

9.Stevia,stevioside and special groups of the population:nutritional significance 9.1Scientists thought that using stevia extracts as sweeteners could lower the blood sugar content and lose weight for diabetics and it was also a safe sweetener for phenylketonuria patients compared with other aromatic sweeteners. 9.2Various scientific experiments conducted on humans conclude that stevioside could lower the blood pressure with no adverse effect which was good for hypertension patients. Scientists also found the mechanism was by the inhibition of Ca2+ influx from extracellular fluid.

10.Stevioside and caries 10.1Previous experiments indicated that stevioside and rebaudioside had nothing to do with the caries. 10.2Usage of stevioside for sweetening purpose is pretty low as only high concentration of stevioside would inhibit the bacteria, so the main contribution for stevioside is in its replacement with the cariogenic sugars.

Assignment 1 Chemical Properties:Tetrahydrofuran Melting Point

-108 C, 165.15 K [|Sigma-Aldrich] -108.4 C, 164.75 K [|wikipedia] 164.582-164.586 K, Mean Value164.584 K, 164.584 K [|European Journal of Organic Chemistry] -108.38 C, 164.77 K [|CRC Handbook] -108.5 C, 164.65 K [|Inchem]

Boiling Point 339.115 K, 339.115 K [|Journal of Chemical & Engineering Data] 338.96 K, 338.96 K [|Journal of Chemical & Engineering Data] 66 C, 339.15 K [|CRC Handbook] 339.2 K, 339.2 K [|Journal of Chemical & Engineering Data] 338-340 C, Mean value 339 K, 339 K [|NIST]

Density 0.8820 g/cm^3, 0.8820 g/ml [|Journal of Solution Chemistry] 0.889 g/ml, 0.889 g/ml [|Sigma-Aldrich] 0.8833 g/cm^3, 0.8833 g/ml [|CRC Handbook] 0.8892 g/cm^3, 0.8892 g/ml [|wikipedia] 0.8821 g/cm^3, 0.8821 g/ml [|Journal of Solution Chemistry]

Refractive Index 1.405, 1.405 [|CRC Handbook] 1.40487, 1.40487 [|Journal of Chemical & Engineering Data] 1.40443, 1.40443 [|Journal of Chemical & Engineering Data] 1.40512, 1.40512 [|Journal of Chemical & Engineering Data] 1.4048, 1.4048 [|Journal of Chemical & Engineering Data]

Flash Point -17 C, 256.15 K [|Alfa] -17.22 C, 255.93 K [|Wolfram Alpha] 252 K, 252 K [|Journal of Chemical Information and Computer Sciences] -21 C, 252.15 [|Acros Organics] -20.6 to -20.8 C, Mean Value -20.7 C 252.45 K [|Journal of Hazardous Materials]