Organic compounds -- part of the class 532-570 series – Organic compounds – Phosphorus esters
Reexamination Certificate
2002-11-12
2004-12-21
Richter, Johann (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Phosphorus esters
Reexamination Certificate
active
06833467
ABSTRACT:
BACKGROUND OF THE INVENTION
U.S. Pat. No. 4,454,064 discloses a method for preparing pentaerythritol phosphate alcohol, which comprises reacting pentaerythritol and POCl
3
in dioxane solvent at 75-125° C. The pentaerythritol phosphate alcohol prepared is an intermediate that can be used to synthesize PU flame retardants and plasticizers. HCl gas is also generated in this method, and a large amount of water is required to wash away HCl from the product mixture. Moreover, an excessive amount of POCl
3
is used in this method, which results in a residue solution containing unreacted POCl
3
.
U.S. Pat. No. 4,478,998 (1984) discloses a method for synthesizing amino-s-triazine salt of a phosphoric acid from pentaerythritol phosphate alcohol. The amino salt synthesized can be used as a flame retardant additive for special polymeric compositions.
SUMMARY OF THE INVENTION
The present invention provides a waste-reduction process for producing pentaerythritol phosphate alcohol. The features of the process of the present invention are as follows:
1. The process uses P
2
O
5
as a reactant.
2. The process uses a mechanochemical synthesis method and uses a ball mill as a reactor.
3. The process uses an alkyl benzene, such as toluene or xylene, as a solvent. The alkyl benzene may have one or two identical or different alkyls having 1 to 5 carbons.
4. The solvent used in the process is pre-heated to 70-150° C.
5. The process uses metal halide MX
2
, such as MgCl
2
etc., as a catalyst, wherein M=Mg, Zn, or Al; and X=Cl, or Br. The weight ratio of the catalyst to pentaerythritol is 1:99 to 5:95.
Compared to the conventional process, a waste-reduction process for producing pentaerythritol phosphate alcohol according to the present invention has the following three advantages: (a) no generation of waste gas of HCl; (b) free of a waste aqueous solution generated from neutralization of HCl waste gas; and (c) avoiding handling of a residue solution containing unreacted POCl
3
. Since the present invention uses P
2
O
5
to replace POCl
3
, no HCl is generated in the process, and no residue solution containing unreacted POCl
3
is formed. Moreover, the solvent used in the present invention (e.g. toluene) can be recycled, thereby achieving an objective of waste reduction.
Pentaerythritol will become a molten state in toluene at 90-100° C. and can react with P
2
O
5
. Since a molten pentaerythritol has a very high viscosity and is difficult to be agitated, the reaction yield is usually not high. Therefore, a mechanochemical synthesis, e.g. a ball mill, is used to achieve an ideal agitatioin such that pentaerythritol and P
2
O
5
can have a sufficient contact with each other, thereby increasing the yield. The present invention adopts a ball mill process which also achieves the following improvements: increasing the purity, increasing the yield, reducing the particle size, simplifying the process, and without heating/cooling during the reaction.
REFERENCES:
patent: 4454064 (1984-06-01), Halpern et al.
patent: 5237085 (1993-08-01), Telschow et al.
patent: 6455722 (2002-09-01), Vyverberg et al.
patent: 6737526 (2004-05-01), Ma et al.
Chen Wen-Yo
Ma Chong
Peng Yuen-Hsin
Bacon & Thomas PLLC
Chung-Shan Institute of Science & Technology
Richter Johann
Sackey Ebenezer
LandOfFree
Method for preparing pentaerythritol phosphate alcohol by... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for preparing pentaerythritol phosphate alcohol by..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for preparing pentaerythritol phosphate alcohol by... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3333392