# Tag Info

14

Can sugars dissolve in liquid ammonia? Yes, according to Ref.1, liquid ammonia is used to extract sugars in sugar-beet chips: 5.88 kilograms of sugar-beet chips having a moisture content of 5.4 percent and a saccharose content of 68 percent (calculated on the dried substance) are treated in an autoclave of 50-litre capacity with 18 kilograms of liquid ...

8

Vegetable oils are mainly made of glycerol esters of oleic acid, linoleic acid and palmitic acid. For example, the fatty acids extracted from olive oil are a mixture of $74$% oleic acid, $11$% palmitic acid, and $10$% linoleum acid, plus 5% other acids. These proportions are average values that may change from one sample to the next one. The mass proportion ...

5

Those are the same, just shown in a different conformation and a different view. As user55119 points out in the comments, the numbering went awry (in fructose, #2 is the anomeric carbon in the ring form, or the carbonyl carbon in the linear form). Sucrose has no reducing "ends", which it would have if fructose would link via the #5 carbon. If you ...

5

It is probably a mixture of sodium chlorite $\ce{NaClO2}$ and ammonium thiocyanate $\ce{NH4SCN}$. It takes fire with the least drop of water. But the mixture is difficult to do, because these two products have to be totally dry, and ammonium thiocyanate is rather hygroscopic. If they are even a bit wet, they react and take flame by simple contact. It is even ...

5

D and L configuration of sugars: Draw the given sugar (aldose) in the Fischer projection with the most oxidized carbon at the top (i.e. aldehyde carbon). If it is a ketose, make the closest terminal carbon to the keto group at the top. Now: if the $\ce{OH}$ on the bottom chiral center points to the right hand side, the sugar is referred to as D-sugar. if ...

5

The short answer is no. Experiment with a model kit (example) and recognize changing conformers only is about wiggling/rotating bonds which may be gradual in many tiny steps. The transition from one isomer to an other (e.g., $\alpha{} \rightarrow \beta{}$-glucose) is binary like using a light switch; instead of on/off, it is either (R), or (S) – or, in ...

4

β-ᴅ-glucose is more stable than its α-anomer due to the fact that all the −OH groups occupy the equatorial position. This is specifically in aqueous solution. In the solid, you also have to consider the intermolecular interactions between glucose molecules. If this is the case, then why does α-ᴅ-glucose predominate at 30 °C while β-ᴅ-glucose does the same ...

3

The glycoside amygdalin is a product of enzymatic biosynthesis. Its hydrolysis produces 2 molecules of glucose, benzaldehyde and hydrogen cyanide. Mixing potassium cyanide and sugar ( = sucrose = combined glucose + fructose) does not produce amygdalin. Neither you would get it, mixing glucose, benzaldehyde and hydrogen cyanide.

2

Per-O-acetyl-glucopyranoside chemical structure is shown below. It is a fully acetylated glucose saccharide unit in the pyranose ring form. It is mentioned in Molbase and Chemsrc. Pubchem prefers calling it B-L-Glucose pentaacetate and Chemspider 1,2,3,4,6-penta-O-acetyl-B-L-glucopyranose. A search for CAS 66966-07-2 should return an assortment of suppliers ...

2

Dextrose equivalent $(DE)$ is a measure of the amount of reducing sugars present in a sugar product, expressed as a percentage on a dry basis relative to dextrose (glucose). Commercial sugar products are generally characterized by their dextrose equivalent $(DE)$ value (Ref.1). The theoretical definition of $DE$ is given by: DE = \frac{\text{Reducing power ...

1

I would be curious to know if you still have that source claiming the glucose becomes uncyclized. In any case, I asked my biochem prof your question and he said nothing really changes especially for cyclized glucose. Here's why nothing would change: the pKa for a primary alcohol is around 15. This means you're going to have to increase the pH to at least 15 ...

1

I hope you are familiar with the concept of a glucopyranoside. Acetylated means that at least one hydrogen atom has been replaced by an acetyl group $\ce{-C(=O)-CH3}$, typically abbreviated as $\ce{Ac}$. It is connected to the rest of the structure by the bond I have drawn at the front. O-acetylation means that the substitution occurred on an oxygen atom. ...

1

Glucose is the hexose that projects its hydroxyl groups at positions C2, C3 and C4 as well as its CH2OH off C6 in the equatorial direction (in its low energy conformer that is). In the β and α configurations, its anomeric carbon C1 projects the hydroxyl in the equatorial and axial direction, respectively. The D and L forms are mirror images in which all ...

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