Chemical Engineering Searching Best Practices

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Chemical engineering is the systematic management of raw materials to produce useful products. Chemical engineers create products using fundamental scientific principles of chemistry, physics, distillation, reaction design, and process control. Economic interests and environmental concerns are also of paramount importance in optimized production design.

Most prior art searches in the chemical engineering field require knowledge of fundamental chemical engineering principles in addition to at least one related discipline. For example, a search in the area of reactor design will rarely involve only principles of heat and mass transfer; instead, the search will likely involve more complex areas outside of pure chemical engineering, such as an understanding of fluidized packed bed bioreactors. For a well-rounded prior art searcher in this area, research experience in subjects related to the biosciences or electronics is particularly beneficial.

Obstacles Facing the Searcher

Research in chemical engineering has become increasingly multidisciplinary over the last several decades while fundamental scientific principles in the field have not changed. Pure chemical engineering searches are increasingly rare. However, the multidisciplinary applications of chemical engineering principles make experienced chemical engineers well-suited to search for patent literature within a broad range of engineering disciplines. New research in chemical engineering often applies to the fields of nanotechnology, mechanical engineering, bioengineering, and electrical engineering, and requests for searches in these fields are frequent.

As a corollary, these potential cross-applications sometimes mean that a search is best assigned to a chemical engineer even though the main idea of the invention should be classified differently. The situations below are all examples of searches for which a chemical engineer could be uniquely valuable:

  • A search involving analytic instrumentation (such as the design of a gas chromatograph) may require not only knowledge of analytical chemistry, but also knowledge of advanced principles of mechanical engineering or sensor design, as well as chemical engineering fundamentals.
  • A nanotechnology search for electronics applications may require a chemical engineer’s expertise when the formation of the device is based on chemical vapor deposition or chemical surface engineering.
  • A search on an aerospace vehicle may concern rocket propelling devices which consist essentially of a chemical reactor process to produce heat and a resulting thrust, principles which are well understood by chemical engineers.

Chemical engineering searchers may sometimes need to perform chemical structure searching. To accomplish this, they need to become familiar with tools used to search for specific chemical compounds, either alone or in combination with other chemical engineering processes and materials. Chemical structure searching is discussed in-depth in the Chemistry and Pharmaceuticals best practice article.

Finally, chemical engineering searchers may also need to familiarize themselves with some mechanical engineering concepts and nomenclature for medical device searches which sometimes require a certain level of sophistication beyond picture image searching. Resources for these topics may be found in the Mechanical Engineering and Medical Devices best practice articles.

Searching Patent Documents

Recommended tools for searching patents include any commercial search engine with appropriate data coverage. From a functionality standpoint, the ability to quickly review patent drawings is generally less important than the ability to efficiently parse abstracts when compared to disciplines such as mechanical engineering.

Chemical Structure Searching

Occasionally, chemical structure searching is called for during a search in this discipline. A principal resource for chemical structure searching in patent collections is the REGISTRY on STN for specific/known chemical substances; this file can also be searched by chemical property data. A free resource that is not secure or as carefully regulated as Registry is the ChemSpider online portal, which crawls the web, and selected patent collections, to index structure and property data. If a more comprehensive search is called for, both the Merged Markush Service (MMS) and MARPAT on STN files can be used to cover generically disclosed or claimed chemical substances present in patent documents. SureChem is a partially free chemical based search system that offers SMILES code searching, among other things. Other chemical structure search sources, such as searching the Derwent World Patents Index via Derwent fragmentation codes, are less often consulted due to their cost and difficulty of use. Reaxys is a for-pay Elsevier product that searches multitudes of chemical meta-data in patents and non-patent literature alike including organic chemistry information, synthetic routes, and expanded Markush displays among other fields.

Searching Non-Patent Literature

Due to the multidisciplinary nature of searches in this area, non-patent literature is best searched through a portal that allows access to scientific literature from a number of applicable technology areas. The best-known and widely used of these probably include:

  • Chimica – Chemistry and chemical engineering database (Elsevier)
  • Ei Compendex (Elsevier)
  • Inspec – physics, electrical engineering, electronics, computer science (Institution of Engineering and Technology – IET)
  • NTIS – the National Technical Information Service (US government sponsored research)

Most of these journals can be accessed by using subscriptions to well known hosts such as Dialog, STN, Questel, Ovid (Wolters Kluwer), and/or Engineering Village (Elsevier).

Chemical engineering handbooks are useful to quickly harness related search words for more routine chemical engineering elements of a search (e.g. reactors, unit operations, distillation, heat transfer, etc.) The most well known of these may be Perry’s Chemical Engineer’s Handbook, by Robert H. Perry and Don W. Green, which is in its 8th edition as of 10/2007 (ISBN-13: 978-0071422949). The text of some editions of this resource may also be found through (subscription required).

One major journal title is the Chemical Engineering Journal, published by Elsevier, ISSN: 1385-8947, which may be searched via the web at, which offers a portal to Elsevier’s online database, ScienceDirect. Full text copies of any interesting articles can be purchased from this source.

Also noteworthy are websites such as ChemBlink,Household Products Database and LookChem. Websites like these are useful bookmarks for finding CAS Numbers, structures, product information, safety, and health information related to specific substances.

Specific Search Strategies

These search strategies are examples of specific best practices that can be applied during the course of a search in the area of chemical engineering. These are steps to be taken in addition to accepted search practices that apply to all searches. The information below shows how a search can be applied specifically to this discipline. For a more general progression of search steps, please see the General Searching best practice article.

  • Understanding the search often requires reading one or more technical publications in the field of search where familiarity is lacking.
  • When the subject scope is broad, use resources such as a chemical engineering handbook (e.g. Perry’s Handbook) or published research articles to narrow the scope with more specific search terms (e.g. is it a fluidized bed reactor or a packed bed reactor? If a packed bed reactor, what other terms are typically used for the reactor type and specific media used therein?)
  • Identify related patent documents to determine more specific terms related to art in the field. For example, silica may be one type of media used in a packed bed reactor. However, silica is merely one species of inert media for packed bed reactors. Identify the other species and use them as key words to broaden the search.
  • It can be helpful to try and find the "experimental" section of a patent's specification section--look for experimental results, reaction tables and more.
  • Determining the most preferred compound in any given patent can be tricky considering that there is often a mountain of reaction, dosage, and other chemical information. Experimental procedures described in the patent document can be a clue to identifying the compound that is truly preferred by the patent owner. For example, the amount of a given substance may vary over several trials, and this may be mentioned in the patent document.

Key Classification Areas


The following is a list of general US classification areas that may be applicable to chemical engineering searches. This list is not intended to be inclusive, and the specific subject matter of the search may indicate other classes not listed here. Each class is followed by its formal title, and any additional/explanatory comments are included in parenthesis to further clarify the subject matter.

US Classes
55 Gas Separation (Liquid Purification/Separation)
71 Chemistry: Fertilizers
75 Specialized Metallurgical Processes
95-96 Gas Separation Process and Apparatus
106 Compositions: Coating or Plastic
118 Coating Apparatus
134 Cleaning and liquid contact with solids (Chemical Cleaning)
148 Metal Treatment
159 Concentrating Evaporators
201-203 Distillation (thermolytic and separatory processes; apparatus)
204 Chemistry: electrical and wave energy (Electrochemistry)
205 Electrolysis: processes, compositions used therein, and methods of preparing
208 Mineral oils: processes and products
210 Liquid purification or separation
252 Compositions
261 Gas and liquid contact apparatus
264 Plastic and nonmetallic article shaping or treating: processes
420 Alloys or metallic compositions
422 Chemical apparatus and process disinfecting, deodorizing, preserving, or sterilizing
426 Food or edible material: processes, compositions, and products
427 Coating Processes
429 Chemistry: electrical current producing apparatus, product, and process (Electrochemical Engineering)
430 Radiation imagery chemistry: process, composition, or product thereof (Radiation Imagery Chemistry)
435 Chemistry: molecular biology and microbiology (Biochemical Engineering)
436 Chemistry: analytical and immunological testing (Engineering Immunology)
438 Semiconductor device manufacturing: process (Semiconductor Processing)
501 Compositions: ceramic (Ceramic Compositions)
505 Superconductor technology: apparatus, material, process (Superconductivity)
510 compositions (Cleaning Compositions)
512 Perfume Compositions
516 Colloid systems and wetting agents; subcombinations thereof; processes of (Colloids and Wetting Agents)
518 Chemistry: fischer-tropsch processes; or purification or recovery of products thereof (Purification Chemistry)
520-528 Synthetic Resins or Natural Rubbers series
530 Protein Chemistry and Reactor Design)
532-570 Organic Chemistry (General)
588 Hazardous or toxic waste destruction or containment
700-703 Data processing (Process Control)
977 Nanotechnology


Section C, which encompasses CO1-C14, C21-C23, C25, C30, C40, and C99, covers the chemical arts broadly from a pure science as well as an engineering perspective.

Japanese F-Term

Numerous F-term classifications may apply, depending on the exact nature of the subject matter.


For further reading, searchers should reference the corresponding best practices articles covering chemistry and pharmaceuticals and medical devices. Due to some overlap in the fields, the best practices and sources disclosed in those articles may also be applicable to Chemical Engineering searches.

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