Eucalyptus leaves contain oil gland cells, which can secrete aromatic oil, making eucalyptus leaves have a special aromatic smell. The aromatic oil of eucalyptus, usually called eucalyptus leaf oil, is very important in industry. Eucalyptus leaf steam oil is an ancient industry abroad, but because of the late development of eucalyptus afforestation in China, it didn't really develop into industrial production until the 1960s.
The production of eucalyptus oil in China began at 1958, and a large number of varieties were produced, including eucalyptus citriodora leaf oil, eucalyptus globulus leaf oil and eucalyptus globulus leaf oil. The eucalyptus oil produced is mainly used for foreign trade export, and the domestic use is mostly composed of soap, perfume, cosmetics, ten drops of water, cool oil, mosquito-repellent incense oil and spices. , but the dosage is relatively small.
At present, the eucalyptus trees most planted in South China and Southwest China are longan, eucalyptus urophylla, eucalyptus macrophylla, eucalyptus tenuifolia, eucalyptus citriodora and eucalyptus globulus. Among them, eucalyptus citriodora and eucalyptus globulus have higher aromatic values. The methods of extracting eucalyptus oil from these two kinds of eucalyptus leaves are introduced as follows.
Eucalyptus citriodora leaf oil
The content of essential oil in leaves and branches of eucalyptus citriodora is 0.5-0.75%. The oil content per plant can reach 1- 1.5%, and the highest oil yield per plant can reach 2%. The chemical composition of eucalyptus citriodora leaf oil is mainly citronellal, which generally accounts for 65-85%. However, the content of citronellal varies greatly, with the highest reaching 80-85% and the lowest only 40%. Therefore, cultivated varieties or types are closely related to the quality and content of oil. In production, it is best to treat the harvested leaves within 24 hours, otherwise the aldehyde content of eucalyptus oil will be significantly reduced. Eucalyptus citriodora grows very fast and has strong tillering ability. After the big tree is cut down, many branches germinate and can be used as raw materials for steaming oil. Qiao Lin, dwarf forest and nursery can also be used to establish special forest for leaves of eucalyptus citriodora to meet the needs of perfume industry. Eucalyptus globulus leaf oil
Both eucalyptus globulus leaves and young branches can be used to steam oil, and the oil content accounts for 0.75- 1.5% of the weight of fresh leaves. The suitable time for picking leaves and steaming oil is from April to September, the average oil yield is 1- 1.7%, and the content of cineole in eucalyptus oil accounts for 63-73%. The oil yield is low in winter, and the oil content of eucalyptus only accounts for 60-65%. The oil content of the upper branches and leaves of the crown is higher than that of the lower branches and leaves. The production of eucalyptus oil in China is mainly produced in Guangdong, Guangxi, Yunnan, Fujian, Sichuan and other provinces (regions), and the output is estimated to be 2000-3000 tons. China is one of the major exporters of eucalyptus oil in the world.
Oil content of eucalyptus leaves
Eucalyptus leaf oil can be extracted from eucalyptus leaves by steam distillation, and the general oil yield is 0.8-5.0%. The oil content of eucalyptus leaves varies greatly with different eucalyptus varieties. The following is the oil yield of some different eucalyptus leaves announced by FAO in recent years.
Eucalyptus radiata
Eucalyptus lemon
Urtica eucalyptus
The oil yield of eucalyptus grandis is 3-5%, 0.8- 1.0%, 2.0% and 3.0-4.5%.
Eucalyptus shrub
Eucalyptus globulus
Eucalyptus angustifolia
Eucalyptus albiflora
Eucalyptus albiflora
The oil yield of eucalyptus grandis 1.5-2.0%, oil yield 1.0%, oil yield 2.0-2.5%, oil yield 2.0% and oil yield 2.0%.
The oil production of different eucalyptus leaves in Leizhou Forestry Bureau of Guangdong Province is as follows:
Eucalyptus longan
Eucalyptus Lin Lei 1
Eucalyptus lemon
Eucalyptus tenuifolia
Imported eucalyptus grandis
Eucalyptus peach leaf
Eucalyptus broadleaf
Eucalyptus tannin
Eucalyptus urophylla
The oil content of Eucalyptus grandis was 0.62%, 0.4 1%, 1.72%, 0.83%, 0.8 1%, 0.60%, 0.4 1% and 0.4 1% respectively.
It should be pointed out that the oil content of the same eucalyptus leaves varies greatly throughout the year due to the different photosynthesis. For example, in the Ganges Plain of India, 40 kg of eucalyptus citriodora leaves were collected on May 17, and 736.5 ml of oil was obtained, with an oil yield of about 1.84%. On the other hand, 65438+1October 6 also received 40 kilograms of leaf steam oil, and the oil yield was only 436 ml, and the oil yield was only about 1.0 1%. Therefore, when producing eucalyptus oil, the most suitable harvesting time must be considered to improve the oil yield and increase economic benefits.
Production of eucalyptus oil
Eucalyptus leaf oil is a natural aromatic oil. Steam distillation is often used to produce eucalyptus oil. According to local resources and production scale, direct fire or direct steam production can be used. The small direct fire steam distillation method commonly used in forest areas is introduced as follows:
1, Eucalyptus leaf raw material processing
There are two kinds of picking eucalyptus leaves: one is to combine clear cutting to cut branches and leaves; The second is to cut branches from eucalyptus trees operating in low forests, select tender branches with leaves less than 2 cm in diameter as raw materials, bundle them and transport them to the raw material yard of gasoline plants. In order to prevent eucalyptus oil from volatilizing, raw materials should avoid direct sunlight. Eucalyptus leaves should be processed in time after arrival. Stacking should not be too dense and too long, otherwise it will cause mildew and affect the quality of eucalyptus oil.
2. Selection of distillation site
The site should be located near the raw material production base, with sufficient water, convenient transportation, guaranteed power supply and enough open space for stacking raw materials.
3. Distillation equipment
In forest areas, distillation equipment usually adopts the following specifications:
Distilling pot: The pot body has a diameter of 86 cm and a height of100-10 cm, and can hold about 130- 140 kg of eucalyptus leaves. Condenser: tube bundle condenser or coil condenser can be selected for supporting production, and the condensation area is about 1.5-2.0 square meters.
Oil-water separator: The separator is 20cm in diameter and 20cm in height.
4. Oil steaming operation
Before loading eucalyptus leaves into the pot, check whether the production equipment such as distillation pot and condenser are normal, and repair them in time if leakage is found. After ensuring that the equipment does not leak, eucalyptus leaves can be loaded. When filling the pot, the eucalyptus leaves should be moderately elastic and slightly pressed around the edge of the pot, and the filling should not be too full. Generally, it can be filled to 70-80% of the pot capacity. After putting eucalyptus leaves into the pot, cover the pot cover and connect relevant pipes, and then ignite and distill. At first, the fire will be strong. When the water in the pot has been boiled, the generated steam passes through the raw material layer from bottom to top, and the air in the pot is driven away, so it is necessary to reduce the fire slightly to prevent the air from taking away part of the eucalyptus oil. When the air is exhausted, you can increase the firepower at this time and keep it uniform for distillation. The oil-water mixed gas distilled in the pot enters the condenser through the connecting pipe for condensation and cooling, the condensed distillate enters the oil-water separator for oil-water separation, the separated distillate flows back to the pot for distillation, and the eucalyptus oil is further packaged after removing the residual moisture. After about one hour, it was observed that if the oil content of the distillate was low, the fire should be increased to evaporate the high-boiling components in eucalyptus oil as much as possible. After steaming the oil, cease fire, open the lid and discharge the slag, which can be used as fuel. After the leaf residue is discharged, a certain amount of water is added, which can be used for distillation in the next pot.
Quality standard of eucalyptus oil
At present, eucalyptus oil produced in China is mainly eucalyptus citriodora and eucalyptus globulus. Because of their different compositions and uses, their quality standards are also different. The standards are listed as follows:
1, lemon eucalyptus oil standard
Relative density (15℃)
Citronellal content
Optical rotation (20 degrees Celsius)
ester number
Refractive index (20 degrees Celsius)
solubility
2, eucalyptus oil standard
There are 70% eucalyptus globulus oil, 80% eucalyptus globulus oil and 99% eucalyptus globulus oil. Taking 80% eucalyptus globulus oil as an example, the standards are as follows: 0.8640-0.8770 65-85%+3-312-601.451~1.44.
Color shape
sweet taste
Optical rotation (20 degrees Celsius)
Miscibility (20 degrees Celsius)
Relative density (20 degrees Celsius)
Eucalyptol,%
Refractive index (20 degrees Celsius)
3. According to the pharmacopoeia standard, eucalyptus oil is colorless to yellowish liquid, with the characteristic aroma of eucalyptus oil of +2 ~+9 degrees, completely soluble in 5 times of 70% ethanol, 0.909-0.919 ≥ 801.4590-1.4650.
This product is the volatile oil obtained by steam distillation of fresh leaves of eucalyptus globulus of Myrtaceae or other plants of the same genus. The content of eucalyptus oil (C 10H 18O) shall not be less than 70% (ml/ml).
Description: This product is a colorless or yellowish liquid, with special fragrance, slightly like camphor, and pungent and cool taste. Soluble in ethanol (70%); The relative density is 0.905-0.925 and the refractive index is 1.458- 1.470. Use of eucalyptus oil
Eucalyptus leaf oil can be divided into medical oil, perfume oil and industrial oil according to its use.
Eucalyptus globulus oil is widely used in medicine. Eucalyptus globulus oil has anti-bacterial effect, especially on upper respiratory tract infection and chronic bronchitis. Through clinical bacteriostatic experiments, it is found that eucalyptus globulus leaf oil has bacteriostatic ability, and the effect of treating pulmonary tuberculosis patients by inhalation and tracheal drip is satisfactory. It seems to be superior to other anti-tuberculosis drugs in eliminating common symptoms, especially cavity closure. Eucalyptus globulus oil can also be used for some skin diseases, and as a washing agent, deodorant and analgesic for patients with neuropathy. In addition, eucalyptus globulus oil is also commonly used in ten drops of water, cooling oil, wind oil, mosquito repellent oil, cough medicine and so on.
Lemon eucalyptus oil is used in spices and daily chemical products. Contains citronellal, which can be used to synthesize menthol and thymol essence. Rosanol and limonol can also be separated from eucalyptus citriodora oil, which can be used to prepare perfume, soap, essential oil and prickly heat powder.
Industrial eucalyptus oil can be used as additives, surfactants and fungicides in flotation ores and detergents. Eucalyptus leaf oil is a natural cleaner. Usually, if there is chewing gum, it is difficult to wash off fabrics such as clothes and carpets. Recently, it has been found that it is very easy to wash off such dirt marks by using eucalyptus oil as a detergent. In-depth study also found that eucalyptus oil has high surface activity and bactericidal ability, and it is rich in sources and does not produce pollution. It is indeed an ideal natural emulsifier and bactericide. Therefore, Australia has begun to produce eucalyptus oil for decontamination or sterilization. Its main products are eucalyptus oil air cleaner or disinfectant, high-efficiency foam soap, medicinal soap and other products.
Comprehensive utilization of eucalyptus
Process for producing tannin extract from eucalyptus globulus and eucalyptus citriodora leaves
In order to comprehensively utilize eucalyptus resources, eucalyptus leaves cooked with eucalyptus oil can also produce tannin extract. The process flow is as follows:
1, raw materials are chopped.
Tannin is the effective component of tannin extract. The diffusion ability of tannin through cell wall is very small, so it is necessary to increase the contact surface between solvent and cell when leaching tannin with solvent. Therefore, in order to obtain the extraction effect, eucalyptus leaves should be crushed, but the crushing is too fine, which brings a lot of trouble to the post-treatment of the extract. In practice, the tender branches and leaves of eucalyptus are generally cut into small pieces of 3-5 cm with a chopper.
2. Pre-soaking and cleaning
Put the chopped eucalyptus branches and leaves into the pool and wash them with cold water to remove the entrained sediment and other impurities and improve the product quality.
3 Leaching
Water is used as the solvent for extracting eucalyptus tannin extract, but soft water must be used. Water containing magnesium salt and calcium salt will precipitate, which will reduce the extraction rate and is not conducive to extraction. The pH value of water should not exceed 7.0. The ratio of raw materials to water is 1: 3, and the suitable extraction temperature is 95 degrees Celsius. In actual production, countercurrent circulation leaching method is adopted to leach under the condition of temperature change. At first, the temperature was low, and gradually increased until it finally reached the highest temperature. The extraction time is 4 hours, the extraction coefficient is 250%, and the concentration is 4 Baume degrees. Four barrels are combined into 1 group, the liquid is changed every 2 hours, and the raw materials are extracted 7 times per barrel.
evaporate
The concentration of leachate is very low, so evaporation is needed to improve the concentration of leachate. Because tannin is very sensitive to heat, it is necessary to reduce the temperature as much as possible when evaporating, so vacuum evaporation must be used. The leaching solution evaporated from 4 Baume to 16- 18 Baume.
dry
In order to facilitate packaging and transportation, the evaporated concentrated solution was dried into powdered tannin extract by centrifugal spray drying, and the water content of the product was 8- 12%.
Eucalyptus leaf tannin extract is a brown powder product, which is non-toxic, tasteless, pollution-free, soluble in cold water, easy to absorb moisture, and has a slight caramel flavor and eucalyptus oil flavor. The main component of eucalyptus tannin extract is tannin, which belongs to mixed hydrolysis. Others also contain reducing agents and water-insoluble substances. Hydrolyzed tannin is a compound containing ester bond and sugar bond, which is easily hydrolyzed by acid and enzyme to produce non-tanned products.
Eucalyptus leaf tannin extract has the following uses:
1, used as reinforcing agent for gypsum model.
Eucalyptus leaf tanning type water reducer can be used as retarding reinforcing agent for building gypsum board, and the general addition amount is 0.25-0.3% of the water consumption, which can increase the water-gypsum ratio to 1: 1.5- 1.7, and the gypsum has good fluidity, delayed setting time, good and uniform crystallization, improved flexural strength by about 30%, and improved compressive strength.
2. Used as an additive for slurry ball milling.
1, raw materials are chopped.
Tannin is the effective component of tannin extract. The diffusion ability of tannin through cell wall is very small, so it is necessary to increase the contact surface between solvent and cell when leaching tannin with solvent. Therefore, in order to obtain the extraction effect, eucalyptus leaves should be crushed, but the crushing is too fine, which brings a lot of trouble to the post-treatment of the extract. In practice, the tender branches and leaves of eucalyptus are generally cut into small pieces of 3-5 cm with a chopper.
2. Pre-soaking and cleaning
Put the chopped eucalyptus branches and leaves into the pool and wash them with cold water to remove the entrained sediment and other impurities and improve the product quality.
3 Leaching
Water is used as the solvent for extracting eucalyptus tannin extract, but soft water must be used. Water containing magnesium salt and calcium salt will precipitate, which will reduce the extraction rate and is not conducive to extraction. The pH value of water should not exceed 7.0. The ratio of raw materials to water is 1: 3, and the suitable extraction temperature is 95 degrees Celsius. In actual production, countercurrent circulation leaching method is adopted to leach under the condition of temperature change. At first, the temperature was low, and gradually increased until it finally reached the highest temperature. The leaching time is 4 hours, the leaching coefficient is 250%, and the concentration is 4 Baume degrees. Four barrels are combined into 1 group, the liquid is changed every 2 hours, and the raw materials in each barrel are leached for 7 times.
evaporate
The concentration of leachate is very low, so evaporation is needed to improve the concentration of leachate. Because tannin is very sensitive to heat, it is necessary to reduce the temperature as much as possible when evaporating, so vacuum evaporation must be used. The leaching solution evaporated from 4 Baume to 16- 18 Baume.
dry
In order to facilitate packaging and transportation, the evaporated concentrated solution was dried into powdered tannin extract by centrifugal spray drying, and the water content of the product was 8- 12%.
Eucalyptus leaf tannin extract is a brown powder product, which is non-toxic, tasteless, pollution-free, soluble in cold water, easy to absorb moisture, and has a slight caramel flavor and eucalyptus oil flavor. The main component of eucalyptus tannin extract is tannin, which belongs to mixed hydrolysis. Others also contain reducing agents and water-insoluble substances. Hydrolyzed tannin is a compound containing ester bond and sugar bond, which is easily hydrolyzed by acid and enzyme to produce non-tanned products.
Eucalyptus leaf tannin extract has the following uses:
1, used as reinforcing agent for gypsum model.
Eucalyptus leaf tanning type water reducer can be used as retarding reinforcing agent for building gypsum board, and the general addition amount is 0.25-0.3% of the water consumption, which can increase the water-gypsum ratio to 1: 1.5- 1.7, and the gypsum has good fluidity, delayed setting time, good and uniform crystallization, improved flexural strength by about 30%, and improved compressive strength.
2. Used as an additive for slurry ball milling.
The addition amount is 0.3-0.35% of the raw material based on absolute dryness, the ball milling moisture can be reduced from 55-60% to 465,438+0-45%, the feeding amount can be increased by 25-30%, the ball milling time can be shortened by 5-65,438+00%, and the ball milling efficiency can be improved by more than 35%.
3, used as boiler scale remover
Eucalyptus leaf tannin extract has a good effect on removing carbonate scale formed by long-term use of small and medium-sized boilers, heat exchangers, automobile water tanks and other water containers. The dosage of chemicals should be per ton of boiler water 13- 15 kg, and the dosage of boilers with less than 2 tons of boiler water should not be less than 25 kg. If the pH value of boiler water is still lower than 7.0 after dosing, adjust the pH value of water to 7.0-9.0 with soda ash or trisodium phosphate.
4. Other uses
Eucalyptus leaf tannin extract can be used for tanning, and raw leather can be made into soft leather. In addition, eucalyptus tannin extract can also be used as mineral flotation agent.