In what is considered to be the main pathway of propylene glycol metabolism in mammals, propylene glycol is oxidized by alcohol dehydrogenase to lactaldehyde, then to lactate by aldehyde dehydrogenase. The lactate is further metabolized to pyruvate, carbon dioxide, and water. Lactate also contributes to glucose formation through gluconeogenic pathways. Lactate, via phosphoenol pyruvate, can be detoxified into glucose and stored as glycogen ... Excess production of lactic acid resulting from very large exposures to propylene glycol can produce a metabolic anion gap [anion gap = (Na+) - (Cl - + total CO2)] and metabolic acidosis. Serum levels of >180 mg/L [2.37mM] can result in toxicity.
Synthesis of propylene glycol results in a 1:1 ratio of D and L stereoisomer forms. There is some, although incomplete, information in the literature about stereospecificity of the enzymes in the propylene glycol metabolic pathways ... In the main metabolic pathway, D and L forms of lactaldehyde and lactate are formed. In the horse and rabbit, ADH will oxidize the L form of propylene glycol and lactaldehyde more efficiently than the D form. L-lactic acidosis has been observed in both humans and animals following exposure to propylene glycol). The conversion of lactaldehyde to methylglyoxal by ADH and then to D-lactate by glyoxalase and reduced glutathione is thought to be an alternate route of metabolism ... D-lactate is cleared more slowly than L-lactate and is considered a poor substrate for gluconeogenesis. Methylglyoxal synthetase can convert the substrate, dihydroxyacetone phosphate, to methylglyoxal. However, in conditions where ketone levels are high, such as diabetes or starvation, methylglyoxal synthetase activity is increased, producing more methylglyoxal and D-lactate. Excessive production of D-lactate may result in its accumulation, especially in the brain, which has a low level of catabolizing enzymes. Therefore, in cases of ketosis, excess levels of D-lactate may be exacerbated by propylene glycol. In a third possible metabolic pathway, propylene glycol can be phosphorylated, converted to acetol phosphate, lactaldehyde phosphate, lactyl phosphate, and lactic acid ... Metabolism of D and L forms of propylene glycol in this pathway is species-specific. The rabbit converts the L form of phosphorylated propylene glycol to lactic acid, whereas the rat and mouse can convert both forms. /D and L isomers/
Studies in humans and rodents suggest that the placenta has extremely limited capacity to metabolize propylene glycol. Class III ADH /was isolated/ from full term human placenta and found /to have/ low activity for ethanol and a Km value for octanol that was 100-times higher than the Class I ADH enzyme found in human liver ... ALDH from full-term human placentas had a lower activity and Vmax, and a higher Km value than ALDH isoenzymes from liver. In rats, placenta was found to have no ADH activity and ALDH activity in placenta was found to be 4-7% of liver activity
EXPOSURE. Propylene glycol (PG) production capacity in the US was 1312 million pounds (596 kilotons) in 1998. Domestic demand was 1050 million pounds (477 kilotons). PG is used as an ingredient in cosmetics at concentrations of <0.1% to >50%. Approximately 4000 cosmetic products contained PG in 1994. Uses of PG, with percent of demand, are: unsaturated polyester resins, 26 percent; antifreeze and de- icing fluids, 22 percent; food, drug and cosmetics uses, 18 percent; liquid detergents, 11 percent; functional fluids (inks, specialty anti-freeze, de-icing lubricants), 4 percent; pet foods, 3 percent; paints and coatings, 5 percent; tobacco, 3 percent; miscellaneous, including plasticizer use, 8 percent. HEALTH. Propylene glycol (PG) is not acutely toxic. The lowest oral LD50 values range between 18 and 23.9 mg/kg (5 different species) and the reported dermal LD50 is 20.8 mg/kg. PG is essentially nonirritating to the skin and mildly irritating to the eyes. Numerous studies support that PG is not a skin sensitizer. Repeated exposures of rats to propylene glycol in drinking water or feed did not result in adverse effects at levels up to 10% in water (estimated at about 10 g/kg bw/day) or 5% in feed (dosage reported as 2.5 g/kg bw/day) for periods up to 2 years. In cats, two studies of at least 90 days duration show that a species-specific effect of increased Heinz bodies was observed (NOAEL = 80 mg/kg bw/day; LOAEL = 443 mg/kg bw/day), with other hematological effects (decrease in number of erythrocytes and erythrocyte survival) reported at higher doses (6-12% in diet, or 3.7-10.1 g/cat/day). Propylene glycol did not cause fetal or developmental toxicity in rats, mice, rabbits, or hamsters (NOAELs range from 1.2 to 1.6 g/kg bw/day in four species). No reproductive effects were found when propylene glycol was administered at up to 5% in the drinking water (reported as 10.1 g/kg bw/day) of mice. Propylene glycol was not a genetic toxicant as demonstrated by a battery of in vivo (micronucleus, dominant lethal, chromosome aberration) and in vitro (bacterial and mammalian cells and cultures) studies. No increase in tumors was found in all tissues examined when propylene glycol was administered in the diet of rats (2.5 g/kg bw/day for 2 years), or applied to the skin of female rats (100% PG; total dose not reported; 14 months) or mice (mouse dose estimated at about 2 g/kg bw/week; lifetime). These data support a lack of carcinogenicity for PG. ENVIRONMENT. ... Measured freshwater aquatic toxicity data for fish, daphnia and algae report LC/EC50 values of >18,000 mg/L. Therefore, PG is not acutely toxic to aquatic organisms except at very high concentrations. Using an assessment factor of 100 and the Ceriodaphnia data (48- hour EC 50 = 18,340 mg/l), the predicted no effect concentration is 183 mg/L.
来源:Hazardous Substances Data Bank (HSDB)
毒理性
致癌物分类
对人类不具有致癌性(未被国际癌症研究机构IARC列名)。
No indication of carcinogenicity to humans (not listed by IARC).
来源:Toxin and Toxin Target Database (T3DB)
毒理性
吸入症状
干燥的喉咙。咳嗽。
Dry throat. Cough.
来源:ILO-WHO International Chemical Safety Cards (ICSCs)
毒理性
眼睛症状
眼睛干涩。疼痛。瘙痒。
Dryness of eyes. Pain. Itching.
来源:ILO-WHO International Chemical Safety Cards (ICSCs)
毒理性
摄入症状
短期暴露的影响
See Effects of short-term exposure
来源:ILO-WHO International Chemical Safety Cards (ICSCs)
Absorption of orally administered propylene glycol from the gastrointestinal tract, and its removal from the body, follow first order kinetics. Clearance from blood is rapid in humans, with a mean half-life of approx. 2 hr. Its metabolism is inhibited by pyrazole, indicating a role for alcohol dehydrogenase in this process. Once absorbed it is readily converted into lactic and pyruvic acids, which then enter the general metabolic pool.
Propylene glycol is readily absorbed from the GI tract and distributed throughout total body water. Propylene glycol accumulation is reported to differ significantly among people maintained on a repetitive oral dosing schedule, due to intersubject variability in clearance.
The uptake of propylene glycol mist by humans was studied using 10% solution in labeled deionized water nebulized into a mist tent. Less than 5% of the mist entered the body, and of this 90% lodged in the nasopharynx and rapidly disappeared into the stomach. Very little was found in the lungs.
Intravenous administration of propylene glycol in amounts of 3-15 g/sq m is followed by plasma concentration of 60 to 425 ug/mL, respectively, with ... a volume of distribution of 0.51 to 0.88 L/kg, and a clearance rate of about 300 mL/min/1.73 sq m. Cerebrospinal fluid concentrations are as high as 85% of the serum concentrations.
1.周国泰,化学危险品安全技术全书,化学工业出版社,1997 2.国家环保局有毒化学品管理办公室、北京化工研究院合编,化学品毒性法规环境数据手册,中国环境科学出版社.1992 3.Canadian Centre for Occupational Health and Safety,CHEMINFO Database.1998 4.Canadian Centre for Occupational Health and Safety, RTECS Database, 1989
Novel synthesis of 2H-1,5-benzoxathiepin-3(4H)-one and 5H-4,1-benzoxathiepin-3(2H)-one derivatives and chemical properties evaluation
作者:Taras M. Tarasiuk、Olena O. Shyshkina、Yulian M. Volovenko、Volodymyr V. Medviediev、Tetiana A. Volovnenko、Oleg V. Shishkin
DOI:10.1007/s00706-015-1500-1
日期:2015.10
for the synthesis of 2H-1,5-benzoxathiepin-3(4H)-one and 5H-4,1-benzoxathiepin-3(2H)-one derivatives have been developed. Carbonyl group of 2H-1,5-benzoxathiepin-3(4H)-one has been protected by cyclic and acyclic ketals. Interaction of 2H-1,5-benzoxathiepin-3(4H)-one with NaBH4, hydroxylamine, hydrazines, and Br2 has been investigated. Strecker reaction has been carried out for the synthesis of corresponding
摘要已开发出合成2 H -1,5-苯并氧杂噻吩-3(4 H)-one和5 H -4,1-苯并氧杂噻吩-3(2 H)-one衍生物的新方法。2 H -1,5-benzoxathiepin-3(4 H)-one的羰基已被环状和非环状缩酮保护。研究了2 H -1,5-benzoxathiepin-3(4 H)-one与NaBH 4,羟胺,肼和Br 2的相互作用。进行了Strecker反应以合成相应的α-氨基酸。Horner-Wadsworth-Emmons和Michael反应的结合可以得到β-取代的羧酸的衍生物。另外,2 H -1,5-苯并噻吩-3(4 H)-1参与了Johnson-Corey-Chaykovsky反应。 图形概要
Cobalt-catalyzed regioselective cross-dehydrogenative C O coupling of 1-naphthylamide derivatives with diols
The cobalt-catalyzed regioselective C-H alkoxylation of 1-naphthylamide with diols through a bidentate-chelation assistance has been developed. In this transformation, not only linear diols, but also branched diols and oligoethylene glycols were tolerated under current reaction conditions, affording the corresponding hydroxyalkyl aryl ethers. In addition, control experiments suggested that picolinoyl
Zinc monoglycerolate as a catalyst for the conversion of 1,3- and higher diols to diurethanes
作者:Sanjitha Kulasegaram、Uzma Shaheen、Terence W. Turney、Will P. Gates、Antonio F. Patti
DOI:10.1039/c5ra05032d
日期:——
An efficient approach to the synthesis of diurethanes from 1,3- and higher diols (n ≥ 3) is described.
一种从1,3-和更高的二醇(n ≥ 3)合成二尿酰胺的高效方法被描述。
Improved Synthesis of Severely Sterically Hindered Amino-Ether Alcohols and Diaminopolyalkenyl Ethers Using a High Activity Powder Catalyst
申请人:Elia Christine Nicole
公开号:US20080058553A1
公开(公告)日:2008-03-06
The present invention relates to a process for preparing severely sterically hindered secondary amine ether alcohols and diamine polyalkenyl ethers by reacting a primary amino compound with a polyalkenylether glycol in the presence of a high activity nickel powder hydrogenation catalyst which is marked by high conversion of reactants and increased selectivity to desired final product.
Yttria-Zirconia Based Lewis Acid: An Efficient and Chemoselective Catalyst for Acylation Reactions
作者:Pradeep Kumar、Rajesh Kumar Pandey、Mandar S. Bodas、Mohan K. Dongare
DOI:10.1055/s-2001-10778
日期:——
Yttria-zirconia based strong Lewis acid efficiently catalyzes acylation of alcohols, amines and thiols under environmentally safe, heterogeneous reaction conditions with high selectivity and in excellent yields.