The chemical composition of crude glycerol mainly varies with the type of catalyst used to produce biodiesel, the transesterification efficiency, recovery efficiency of the biodiesel, other impurities in the feedstock, and whether the methanol and catalysts were recovered. All of these considerations contribute to the composition of the crude glycerol fraction. For instance, Hansen et al. studied the chemical compositions of 11 crude glycerol collected from 7 Australian biodiesel producers and indicated that the glycerol content ranged between 38% and 96%, with some samples including more than 14% methanol and 29% ash.
Such variations would be expected with small conversion facilities. In most cases, biodiesel production involves the use of methanol and a homogeneous alkaline catalyst, such as sodium methoxide and potassium hydroxide. Accordingly, methanol, soap, catalysts, salts, non-glycerol organic matter, and water impurities usually are contained in the crude glycerol.
For example, crude glycerol from sunflower oil biodiesel production had the following composition (w/w): 30% glycerol, 50% methanol, 13% soap, 2% moisture, approximately 2-3% salts (primarily sodium and potassium), and 2-3% other impurities. Moreover, while the same feedstocks were employed, the crude glycerol from alkali- and lipase-catalyzed transesterifications contained different purities of glycerol. The salt content in crude glycerol, from biodiesel production via homogeneous alkaline catalysts, ranged from 5% to 7% which makes the conventional purification techniques more costly. Heterogeneous processes using enzymes and solid metal-oxide catalysts have been promoted as good alternatives to homogeneous alkaline catalysts in terms of improving the quality of crude glycerol.
However, even in heterogeneous transesterification processes, impurities existing in the natural raw feedstocks tend to accumulate in the glycerol phase. Therefore, purification of crude glycerol is required, in most cases, to remove impurities in order to meet the requirements of existing and emerging uses.
Saturday, February 23, 2019
Friday, February 22, 2019
The effect of glycerin on the skin
Glycerol has the advantages of moisturizing and moisturizing, moisturizing the skin and preventing skin cracking. Correct use of glycerol skin care can play a very good moisturizing and skin care effect. Glycerol is not harmful, but we need to pay attention to the use of the environment and concentration, some glycerol need to be diluted before it can be used, and direct use is slightly irritating to the skin.
Glycerin for Skin Benefits:
2.Protective benefits
When glycerin is applied to the face, an invisible protective film will be formed on the skin surface, which will isolate the outside air from the skin and protect the skin against the invasion of the outside environment. So before going out in winter, apply glycerin on bare skin to protect skin.
3.Frost crack prevention
There is another advantage of using glycerin in winter, that is, to prevent skin frost cracking, winter hands and feet prone to chilblain, after the weather turns cool, stick to the use of glycerin every day, can play a role in preventing chilblain. If the lips are easy to crack, then it can be applied to the lips, just be careful not to eat.
Notes for glycerol skin care:
1.Attention should be paid to air humidity in winter when skin is dry. Glycerol can absorb water and keep skin moist and moist for a long time. But this method is limited to the south where the air is wet. If the air is dry in the north, glycerol can't absorb moisture from the air, and it will absorb moisture from the skin, so the skin will get drier and drier. To use glycerin, look at the air humidity of the day above 50, then you can rest assured that the use of glycerin.
2.Glycerol skin care should not be directly applied glycerol, although it can moisturize the skin, but because of the high concentration of glycerol, directly applied to the skin may bring some irritation, and too high concentration of glycerol directly applied to the skin, strong water absorption may also absorb water from the skin. So before using glycerin, it's better to dilute it with water.
3.Pay attention to the fact that glycerol is not oil, but the skin will feel more oil after applying glycerol, so glycerol is more suitable for people with dry skin, if it is oily skin, then the use of glycerol will easily make the skin greasy and uncomfortable, so the use of glycerol is best based on their skin.
Glycerin for Skin Benefits:
- Moisturizing ,glycerin is very suitable for people with dry skin. Glycerin rubbing on the skin can moisturize dry skin. Then glycerin will form a protective film on the skin surface, which will lock up the moisture in the skin and reduce the loss of water. And glycerol also absorbs moisture from the air itself, keeping the skin moist for a long time.
2.Protective benefits
When glycerin is applied to the face, an invisible protective film will be formed on the skin surface, which will isolate the outside air from the skin and protect the skin against the invasion of the outside environment. So before going out in winter, apply glycerin on bare skin to protect skin.
3.Frost crack prevention
There is another advantage of using glycerin in winter, that is, to prevent skin frost cracking, winter hands and feet prone to chilblain, after the weather turns cool, stick to the use of glycerin every day, can play a role in preventing chilblain. If the lips are easy to crack, then it can be applied to the lips, just be careful not to eat.
Notes for glycerol skin care:
1.Attention should be paid to air humidity in winter when skin is dry. Glycerol can absorb water and keep skin moist and moist for a long time. But this method is limited to the south where the air is wet. If the air is dry in the north, glycerol can't absorb moisture from the air, and it will absorb moisture from the skin, so the skin will get drier and drier. To use glycerin, look at the air humidity of the day above 50, then you can rest assured that the use of glycerin.
2.Glycerol skin care should not be directly applied glycerol, although it can moisturize the skin, but because of the high concentration of glycerol, directly applied to the skin may bring some irritation, and too high concentration of glycerol directly applied to the skin, strong water absorption may also absorb water from the skin. So before using glycerin, it's better to dilute it with water.
3.Pay attention to the fact that glycerol is not oil, but the skin will feel more oil after applying glycerol, so glycerol is more suitable for people with dry skin, if it is oily skin, then the use of glycerol will easily make the skin greasy and uncomfortable, so the use of glycerol is best based on their skin.
Thursday, February 14, 2019
Characteristics of different types of glycerol
Glycerol is similar to water and simple aliphatic alcohols in solubility because of the presence of OH root. It can be completely miscible with water, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-amyl alcohol, ethylene glycol, propylene glycol and phenol. The solubility in acetone at room temperature is 5% of the weight of acetone. The soluble glycerol in 100% ethyl acetate is 9. There is also a limited solubility in dioxane and ether, but glycerol is almost soluble in high molecular weight aliphatic alcohols, oils, hydrocarbons and chlorinated solvents such as hexane, benzol and chloroform. It can be completely miscible with ethylene glycol monomethyl ether and ethylene glycol monoethyl ether, but its solubility in ethylene glycol monomethyl butyl ether is limited. The introduction of hydroxyl and amino groups into aliphatic and aromatic hydrocarbons increases the miscibility with glycerol, but the introduction of alkyl groups decreases the miscibility with glycerol. If the alkyl chain of secondary or tertiary amine of monoamine increases, the miscibility of the compound with glycerol decreases. Heterocyclic compounds containing one nitrogen atom are usually easily miscible with glycerol. The solubility of gases in glycerol, as in other liquids, is related to pressure and temperature.
The surface tension of 99% glycerol is about 52 dynes/cm at 30℃. The surface tension of glycerol is less than that of water, but greater than that of most liquid organic compounds. The surface tension of glycerol decreases with temperature and height. The surface tension of glycerol increases slightly after adding water, but decreases significantly after adding ethanol.
Commodity glycerol can be divided into crude glycerol and refined glycerol. Refined glycerol, or distilled glycerol, can be divided into several grades. The United States classifies refined glycerol into the following grades:
American Pharmacopoeia Glycerol, which meets the chemical pure glycerol standard of American Pharmacopoeia. It is mainly used in food, medicine and industries requiring high purity glycerol.
High specific gravity glycerol is industrial pure glycerol with glycerol content not less than 98.7%.
Explosive glycerin is produced according to the special requirements of nitroglycerin and Dana explosive manufacturer. Its concentration is similar to that of high specific gravity glycerin.
Yellow distilled glycerol is used in industries where the purity, specific gravity and concentration of glycerol are not required.
Glycerol is one of the important nutrients of bacteria, yeasts and moulds. Glycerol is widely used as a fungicide or to inhibit the production and reproduction of microorganisms when it is used as a nutrient in high concentrations. The effect of glycerol as a fungicide is probably due to the extraction of water from bacterial cells.
The recommended standard for glycerol industry in China is GB/T 13206-2011. Each company's glycerol products have its own enterprise standards on the basis of meeting relevant national standards.
The main sources of glycerol are Malaysia, Indonesia, Thailand and other countries.
The surface tension of 99% glycerol is about 52 dynes/cm at 30℃. The surface tension of glycerol is less than that of water, but greater than that of most liquid organic compounds. The surface tension of glycerol decreases with temperature and height. The surface tension of glycerol increases slightly after adding water, but decreases significantly after adding ethanol.
Commodity glycerol can be divided into crude glycerol and refined glycerol. Refined glycerol, or distilled glycerol, can be divided into several grades. The United States classifies refined glycerol into the following grades:
American Pharmacopoeia Glycerol, which meets the chemical pure glycerol standard of American Pharmacopoeia. It is mainly used in food, medicine and industries requiring high purity glycerol.
High specific gravity glycerol is industrial pure glycerol with glycerol content not less than 98.7%.
Explosive glycerin is produced according to the special requirements of nitroglycerin and Dana explosive manufacturer. Its concentration is similar to that of high specific gravity glycerin.
Yellow distilled glycerol is used in industries where the purity, specific gravity and concentration of glycerol are not required.
Glycerol is one of the important nutrients of bacteria, yeasts and moulds. Glycerol is widely used as a fungicide or to inhibit the production and reproduction of microorganisms when it is used as a nutrient in high concentrations. The effect of glycerol as a fungicide is probably due to the extraction of water from bacterial cells.
The recommended standard for glycerol industry in China is GB/T 13206-2011. Each company's glycerol products have its own enterprise standards on the basis of meeting relevant national standards.
The main sources of glycerol are Malaysia, Indonesia, Thailand and other countries.
Friday, February 1, 2019
Application of monofatty acid glycerides
The solubility of mono-fatty acid glycerides depends not only on the content of diesters in mono-fatty acid glycerides, but also on the type of fatty acid groups (saturated or unsaturated). Monolipid and double-fat glycerides exist in a variety of crystalline or amorphous forms. At different temperatures, it can interact with different proportions of water to form gel hydrates together. The gelatin phase can be obtained by melting the glycerides of mono fatty acids or heating up to the melting point of monoglyceride and slightly higher than the melting point of the water. The mixture of monoglycerides and water (> 50%) mixed at 55-68 OC formed a concentric bimolecular dispersion. After mechanical agitation, a transparent gel like state was obtained. At this time, monofatty acid glycerides have the best emulsifying properties.
Mono fatty acid glyceride is a non-ionic surfactant with a two affinity structure. The HLB value is about 2.8-3.8.. In the oil water system, monoglyceride can interact with these two substances. This dual action enables it to form a boundary film on the oil water interface. Thus the interfacial tension is reduced. High purity (90%) monofatty acid glycerides have stronger effects than common purity (45% - 60%) monofatty acid glycerides.
In the food industry, mono-fatty acid glycerides can be used as additives to improve the structure of dough, which can improve the quality and flavor of cereal flour and starch foods. If it can make bread soft, big and elastic. In a few days, no crumbs, no hardness and no change in flavor; in cake making, mono-fatty acid glycerides and proteins can form complex, thus producing stable bubble film, producing cake embryos with small bubbles and large and soft cakes; in biscuit production, adding 0.3% - 0.5% mono-fatty acid glycerides of flour can make oil dispersed in flour in an emulsified state and improve the quality of cake. The surface structure can prevent oil seepage and improve the brittleness and defilm of biscuits. It makes the pattern clear and not easy to break. When noodles are processed, adding 0.3% - 0.5% mono fatty acid glyceride of flour can make the noodles not easy to rot and taste good. For instant noodles, it can promote the wetting and penetration of water, and is convenient to eat.
In the processing of candy and chocolate, emulsifying and plasticizing of mono-fatty acid glyceride can prevent the separation of grease from butter candy, improve the moisture resistance of candy, reduce deformation, prevent sticking teeth and improve taste. Adding mono-fatty acid glyceride to chocolate can improve its brittleness and effectively prevent damp deformation affecting taste.
In ice cream and beverage, monofatty acid glyceride is the most ideal emulsifier and stabilizer for ice cream production. After adding, the ingredients of ice cream can be mixed evenly, the structure is delicate and smooth, the expansion is moderate, and the taste is good. At the same time, it can improve the shape preservation and storage stability. Solubility and stability can be improved in oily and protein beverages. High purity monofatty acid glycerides can be used in the production of various beverages.
In terms of edible oils and fats, margarine, shortening, oil consumption, peanut butter, etc. are generally added with high purity monofatty acid glycerides as emulsifiers and stabilizers, which can prevent oil-water separation, stratification and improve product quality.
In addition, mono-fatty acid glycerides as emulsifiers and stabilizers are very suitable for the production of cosmetics and pharmaceuticals. The defoamer prepared with mono-fatty acid glyceride and hexaglycol ester can be used in the processing of soybean products, which makes the filtration convenient, the yield of tofu increased and the storage capacity of tofu increased. In addition, it can also be used for dry yeast protection and fruit preservation.
Mono fatty acid glyceride is a non-ionic surfactant with a two affinity structure. The HLB value is about 2.8-3.8.. In the oil water system, monoglyceride can interact with these two substances. This dual action enables it to form a boundary film on the oil water interface. Thus the interfacial tension is reduced. High purity (90%) monofatty acid glycerides have stronger effects than common purity (45% - 60%) monofatty acid glycerides.
In the food industry, mono-fatty acid glycerides can be used as additives to improve the structure of dough, which can improve the quality and flavor of cereal flour and starch foods. If it can make bread soft, big and elastic. In a few days, no crumbs, no hardness and no change in flavor; in cake making, mono-fatty acid glycerides and proteins can form complex, thus producing stable bubble film, producing cake embryos with small bubbles and large and soft cakes; in biscuit production, adding 0.3% - 0.5% mono-fatty acid glycerides of flour can make oil dispersed in flour in an emulsified state and improve the quality of cake. The surface structure can prevent oil seepage and improve the brittleness and defilm of biscuits. It makes the pattern clear and not easy to break. When noodles are processed, adding 0.3% - 0.5% mono fatty acid glyceride of flour can make the noodles not easy to rot and taste good. For instant noodles, it can promote the wetting and penetration of water, and is convenient to eat.
In the processing of candy and chocolate, emulsifying and plasticizing of mono-fatty acid glyceride can prevent the separation of grease from butter candy, improve the moisture resistance of candy, reduce deformation, prevent sticking teeth and improve taste. Adding mono-fatty acid glyceride to chocolate can improve its brittleness and effectively prevent damp deformation affecting taste.
In ice cream and beverage, monofatty acid glyceride is the most ideal emulsifier and stabilizer for ice cream production. After adding, the ingredients of ice cream can be mixed evenly, the structure is delicate and smooth, the expansion is moderate, and the taste is good. At the same time, it can improve the shape preservation and storage stability. Solubility and stability can be improved in oily and protein beverages. High purity monofatty acid glycerides can be used in the production of various beverages.
In terms of edible oils and fats, margarine, shortening, oil consumption, peanut butter, etc. are generally added with high purity monofatty acid glycerides as emulsifiers and stabilizers, which can prevent oil-water separation, stratification and improve product quality.
In addition, mono-fatty acid glycerides as emulsifiers and stabilizers are very suitable for the production of cosmetics and pharmaceuticals. The defoamer prepared with mono-fatty acid glyceride and hexaglycol ester can be used in the processing of soybean products, which makes the filtration convenient, the yield of tofu increased and the storage capacity of tofu increased. In addition, it can also be used for dry yeast protection and fruit preservation.
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